ALBERT

Beschreibung: 〈p〉Publication date: 15 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 123〈/p〉 〈p〉Author(s): Mengzhen Wang, Junjie Yan, Cong Li, Xinyu Wang, Jianjun Xiong, Donghui Pan, Lizhen Wang, Yuping Xu, Xiaotian Li, Min Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Poly(amide-imide)s (PAIs) present limited use in bioapplications due to their poor aqueous solubility and difficulty in functional accessibility. Herein, we prepared PAI-based prodrugs by leveraging aliphatic PAIs as the polymer scaffolds and conjugating camptothecin (CPT) via thiol-disulfide exchange reaction. The degree of CPT attachment can be smoothly controlled by initial feed ratios of PEG and a pyridinedisulfide-modified CPT precursor. Due to the abundant secondary amine groups in PAI backbones, amphiphilic PAI-CPT prodrugs self-assembled into cationic nanoparticles and showed an efficient cellular internalization (〈2 h). The presence of disulfide linkers between PAI scaffolds and CPT endowed PAI-CPT prodrugs a reductive-responsive drug release profile. Moreover, when PAI-CPT prodrug nanoparticles were further used as nanocarriers, doxorubicin (DOX) was additionally encapsulated and variable nanomorphologies (nanospheres, branched nanoparticles) were obtained, and an enhanced chemotherapy efficacy was achieved as well.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719323419-ga1.jpg" width="334" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Yefei Zhang, Alexandra N. Edelbrock, Stuart J. Rowan〈sup〉,〈/sup〉〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Photo-induced thiol-ene crosslinking of allyl-functionalized cellulose nanocrystal (CNC)/polymer nanocomposites allows access to films that mimic the water-enhanced mechanical gradient characteristics of the squid beak. These films are prepared by mixing the functionalized CNCs and polymer in a solvent before solution casting and drying. The photocrosslinking agents are then imbibed into the film before UV exposure. Reported herein are studies aimed at better understanding the effect of the film preparation procedure, film thickness and the conditions under which the UV treatment is carried out. It was found that when the film is heated at a temperature higher than its glass transition temperature (T〈sub〉g〈/sub〉) during the UV irradiation step there is a greater enhancement in the mechanical properties of the films, presumably on account of more efficient crosslinking between the CNC fillers. Moreover, composite films that were compression molded (at 90 °C) before the imbibing step displayed lower mechanical properties compared to the as-cast films, which is attributed to phase separation of the CNC fillers and polymer matrix during this additional processing step. Finally, the film thickness was also found to be a critical factor that affects the degree of crosslinking. For example, thinner films (50 µm) displayed a higher wet modulus ca. 130 MPa compared to ca. 80 MPa for the thicker films (150 µm). Understanding the processing conditions allows access to a larger range of mechanical properties which is important for the design of new bio-inspired mechanical gradient nanocomposites.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718323048-ga1.jpg" width="287" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Sylvain Legrand, Nicolas Jacquel, Hélène Amedro, René Saint-Loup, Jean-Pierre Pascault, Alain Rousseau, Françoise Fenouillot〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the synthesis and properties of poly(1,4-cyclohexanedimethylene-〈em〉co〈/em〉-isosorbide terephthalate) (PCIT) with isosorbide (IS) content ranging from 16 to 61 mol% relative to the total diols amount were investigated. Amorphous polymers were successfully synthesized without isosorbide ring hydration. Glass transition temperature (T〈sub〉g〈/sub〉) linearly increased of 1.1 °C for each molar percent of isosorbide included in the polyester, meanwhile melting temperature (T〈sub〉m〈/sub〉) linearly decreased of 2.1 °C for semi-crystalline samples (up to 25 mol% of isosorbide). Molar masses of semi-crystalline samples were easily increased using high temperature solid-state polymerization (SSP) and reduced viscosity (η〈sub〉red〈/sub〉) higher than 70 mL g〈sup〉−1〈/sup〉 were obtained. Semi-crystalline samples exhibit outstanding impact resistance compared with commercial high performance copolyester, whereas amorphous copolyesters exhibit acceptable mechanical properties coupled with high thermal resistance. Results confirmed the promising association between isosorbide and 1,4-cyclohexanedimethanol to reach tunable thermal and mechanical properties, depending on the targeted applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719302551-ga1.jpg" width="226" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Szczepan Bednarz, Grzegorz Kowalski, Rafał Konefał〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Poly(itaconic acid) (PIA) was synthesized by persulfate initiated free-radical polymerization of ternary Deep Eutectic Solvents (DES) containing equimolar amounts of itaconic acid (IA) as hydrogen-bond donor, quaternary ammonium salt, namely choline chloride (CC) or tetraethylammonium chloride (TEAC) as hydrogen-bonds acceptors, and water as the initiator solvent. The syntheses were carried out at 65 °C for 2 h, and polymers produced were purified by dialysis and by treatment on strong cation exchange resin. The microstructures of the polymers were analysed using 〈sup〉1〈/sup〉H, 〈sup〉13〈/sup〉C and 〈sup〉1〈/sup〉H–〈sup〉13〈/sup〉C HSQC NMR spectroscopy. The unexpected methylene and methine groups resulting from decarboxylation and/or branching as well as choline ester moieties were detected as irregular structures in PIA synthesised in IA-TEAC and IA-CC DES, respectively.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301351-ga1.jpg" width="305" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Marziyeh Ranjbar-Mohammadi, Mahdi Abbasian, Elham Mousavi, Zahra Arab-Bafrani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years, more attention has been drawn to development of three-dimensional 〈em〉in-vitro〈/em〉 tumor models, Multi Cellular Tumor Spheroids (MCTS), due to their similarity to 〈em〉in vivo〈/em〉 tumors models. Interaction of tumor cells with the extracellular matrix (ECM) has an important role in stimulating microenvironmental signaling and MCTS formation. Recently, a number of scaffolds based on natural-nano pattering have been proposed which can superbly mimic the topographical and biochemical features of ECM. In this study, we investigated whether the natural-synthetic polymer nanofibers can promote the three-dimensional (3D) MCTS formation of HT29 colorectal cancer cells in compare to synthetic nanofibers. Nanofibers were fabricated by blending of collagen (Col) and gelatin (Gel) with poly (L-lactide co-ε-caprolactone) (PLCL) polymer, separately. Generally, nanofibers exhibited proper structural properties in term of morphology, hydrophilic nature and mechanical integrity. The results revealed that HT29 colorectal cancer cells can form 3D spheroids with uniform morphology and smooth surface on both Col/PLCL and Gel/PLCL nanofibers while the spheroids were unstable and irregular in shape on PLCL nanofibers. In addition, the cells were dispersed on non-coated plates as confluent cell monolayer. There were no significant differences between the number and diameter of MCTSs on both Col/PLCL and Gel/PLCL nanofibers. On the other hand, the radio resistance of cells on Col/PLCL and Gel/PLCL nanofibers was higher compared with either PLCL nanofibers or non-coated plates. In conclusion, the results showed that scaffolds provided by Col/PLCL and Gel/PLCL nanofibers can mimic the properties of ECM in case of 〈em〉in vitro〈/em〉 MCTS formation so they can be suggested to use in tumor drug screening studies.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718322067-ga1.jpg" width="366" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Xiangyu Pan, Fenming Zhang, Bonnie Choi, Yanlong Luo, Xiaofeng Guo, Anchao Feng, San H. Thang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA) is a promising drug platform as it is non-immunogenic, biocompatible and hydrophilic polymer. It is the first copolymer-drug conjugates to be evaluated in clinical trials. However, it is challenging to obtain well-controlled PHPMA with high conversions via either ATRP or RAFT polymerization in most organic solvents. In this study, we systematically investigate the polymerization of HPMA via RAFT in various solvents using 4-cyano-4-(((ethylthio)thioxomethyl)thio)pentanoic acid as a chain transfer agent. Kinetic experiments demonstrated that the retardation was alleviated in aprotic solvents resulting in low conversions and poor controllability of the polymerization. Variable temperature analyses and molecular dynamic simulation proved the low conversion and poor control of PHPMA was attributed to the hydrogen bonding of the polymeric system and the theoretical results are consistent with our experimental observations.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301843-ga1.jpg" width="389" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Xiansong Wang, Qingyin Wang, Shaoying Liu, Gongying Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fully biobased copolyesters poly(isosorbide-〈em〉co〈/em〉-butylene 2,5-furandicarboxylate) (PISBF) were synthesized from 2,5-dimethylfuran dicarboxylate (DMFD), isosorbide (IS) and 1,4-butanediol (BDO) via transesterification and polycondensation reactions. The resulting copolymers were characterized by 〈sup〉1〈/sup〉H NMR, 〈sup〉13〈/sup〉C NMR, GPC, intrinsic viscosity, DSC, TGA and tensile testing, respectively. The NMR characterizations had confirmed that BDO was successfully introduced into the poly(isosorbide 2,5-furandicarboxylate) (PIF) polyester chains. Over the IS experimental composition range 20–80 % in copolymer chains, PISBF copolymers had 〈em〉T〈sub〉D, 5%〈/sub〉〈/em〉 values higher than 370 °C and 〈em〉T〈sub〉DM〈/sub〉〈/em〉 higher than 405 〈em〉°〈/em〉C, and 〈em〉Tg〈/em〉 values within the range of 55 °C and 150 °C. Introduction of BDO units into PIF chains imparted the PISBF copolyester with better mechanical performance than PIF, thus PISBF copolyesters with IS content of 20–50% were strong and toughened copolymers with Young’s modulus about 1400 MPa, tensile strength at break higher than 53 MPa, and elongation at break higher than 46%.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718320585-ga1.jpg" width="256" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Plínio Ribeiro Rodrigues, Roniérik Pioli Vieira〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The availability of appropriate materials is the main requisite for the design of controlled-release drug delivery systems (DDS), such as nanoparticles, micelles, microparticles, hydrogels and bioconjugates. These delivery platforms must be biocompatible and present appropriate mechanical, physical, chemical and biological properties, allowing the desired control over drug loading and release and granting the benefits of this therapeutic administration route. Atom transfer radical polymerization (ATRP) is presently one of the most used methods of controlled polymerization, applied to synthesize well-defined functional materials and complex polymeric architectures with programmed molecular weights and low dispersity. This review features recent advances in the synthesis of DDS by ATRP, their preparation methods, characteristics and toxicity challenges due to residual metal catalysts. A brief description of controlled polymer architectures, drug loading and release mechanisms, and ATRP techniques is presented to contextualize the readers. It is noted that precise engineering of polymeric materials over molecular architecture, granted by ARTP, is being translated to customized physical properties, allowing fine control over fundamental parameters for the design of DDS.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719302812-ga1.jpg" width="358" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Luzia R.L. Santos, Cláudia E.B. Marino, Izabel C. Riegel-Vidotti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chitosan-based organic-inorganic bio-hybrid nanocapsules, containing benzotriazole, a corrosion inhibitor, were prepared. In view of the versatile chemistry of silicon and the pH sensitivity of chitosan and benzotriazole, two synthesis approaches are presented. In both methods, tetraethoxysilane (TEOS) was used as the silicon source. Particles with different architectures, structural features and pH-dependent release behavior were obtained. The capsules prepared by the sol-emulsion-gel method demonstrated the highest release efficiency at pH 7.0 (∼90%) and pH 9.0 (∼65%) whilst the capsules prepared through layer-by-layer deposition technique showed the best efficiency at pH 3.0 (∼90%). Therefore, in combination, the particles delivered benzotriazole in a wide range of pH (from 3 to 9). The materials were fully characterized at the molecular, mesoscopic and nanometric length scales and the results suggest that they can successfully be applied in pH-sensitive smart coatings for corrosion inhibition.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930103X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Hendrik Schäfer, Claudia Pretschuh, Oliver Brüggemann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉An approach to reduce cycle times in injection molding of poly (lactic acid) through the use of bio-based nucleating agents is presented. Talc is commonly used as nucleant and will be used as the reference in this study. The other investigated additives are kraft lignin, lignosulfonate, and carbon black. This is an in-depth study of certain bio-based nucleating agents for use with poly (lactic acid) under various processing conditions.〈/p〉 〈p〉Bio-based compounds of poly (lactic acid) and different nucleating agents were produced via twin-screw extrusion. Subsequent injection molding yielded standard samples for tensile testing; cycle times were recorded during injection molding. Thermal and mechanical testing showed direct dependence upon the degree of crystallinity in the matrix polymer. The ability of certain bio-based nucleating agents (e.g. kraft lignin) to reduce the cycle time in injection molding was proven.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571831872X-ga1.jpg" width="483" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Joonas Siirilä, Mikko Karesoja, Petri Pulkkinen, Jani-Markus Malho, Heikki Tenhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soft poly(N-vinylcaprolactam) (PNVCL) based nanogels were prepared and surface-decorated with gold nanoparticles (AuNPs). The applicability of the hybrid nanogels (PNVCL-AuNPs) as carriers for low molar mass substances was of special interest. AuNPs protected with a mixture of 11-azidoundecanothiol and 11-mercaptoundecanoic acid were bound to propargyl functionalized PNVCL based nanogels. Acidic groups on the surfaces of AuNPs and PNVCL based nanogels stabilize the particle dispersions against precipitation above the phase transition temperature of PNVCL. Both the neat PNVCL nanogels and the PVCL-AuNPs shrink upon heating the dispersions. Even though the AuNPs are mainly located in the soft surface layer of the nanogels, the PNVCL-AuNPs respond to visible light as well as to radio-frequency (RF) irradiation by shrinking due to the AuNPs acting as nanoheaters. Interactions of linear PNVCL, PNVCL nanogels and PNVCL-AuNPs with two fluorescent probes were studied as function of increasing temperature. Once bound to the polymer the fluorescent probe may or may not be released from it, depending on its polarity and water solubility. Presence of AuNPs changed the release behavior of the water soluble charged fluorescent probe from the nanogels.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301958-ga1.jpg" width="389" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Jozef Kollár, Miroslav Mrlík, Daniela Moravčíková, Béla Iván, Jaroslav Mosnáček〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Series of superabsorbent hydrogels derived from renewable 〈em〉α〈/em〉-methylene-〈em〉γ〈/em〉-butyrolactone (MBL), known as a Tulipalin A, was prepared and examined with respect on their swelling properties and stimuli responsive character. Hydrogels were synthesized by copolymerization of either sodium or potassium 4-hydroxy-2-methylenebutanoate, products resulted from saponification of MBL, with acrylamide in the presence of 〈em〉N,N′〈/em〉-methylenebis(acrylamide) as cross-linker. Hydrogels with various comonomers composition, feed monomers content and variable cross-linking density represent materials with highly tunable characteristics. The effect of temperature, pH and ionic strength of solutions on swelling behavior of the hydrogels was examined. Reversible swelling character of hydrogels in buffer and water was proved as well. Experiments demonstrated reversible ability of hydrogels to swell upon immersing to ultrapure water and deswell in buffer solution.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718321451-ga1.jpg" width="266" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Mandana Akia, Cristobal Rodriguez, Luis Materon, Robert Gilkerson, Karen Lozano〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The antibacterial activity of Nylon 6 nanofiber membranes and commercial gauze pads dipped in Texas sour orange juice were evaluated. The Nylon 6 nanofiber mats were developed using a centrifugal spinning technique. The resultant mats were composed of fibers with average diameter of 209 nm, while the average fiber diameter of the commercial gauze pad was 8.73 µm. The dipping solution was composed of 100% Texas sour orange juice. The samples were immersed in the solution for 5 min. The antibacterial activity against gram-positive, (〈em〉Staphylococcus aureus〈/em〉) and gram-negative (〈em〉Escherichia coli〈/em〉 and 〈em〉Salmonella〈/em〉 sp.) bacteria were evaluated after one day of culture by measuring the inhibition zones. The bacterial tests demonstrated that the addition of the citrus juice to nanofiber membrane increases the degree of inhibition zones from 5.5 mm to 18.5 mm, however; in case of coated gauze pad samples a maximum inhibition zone up to 16 mm was observed. Cell growth was inhibited in the nanofiber membranes, indicating that the nanofiber mats are amenable to be used as easy to remove wound dressings. These results show promising applications in wound care, especially given that the results were achieved in the absence of a sterilization process.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930326X-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 114〈/p〉 〈p〉Author(s): Matea Perić, Robert Putz, Christian Paulik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we used a twin-screw extruder – as an alternative to other, more energy-intensive mechanical methods – to produce nanofibrillated cellulose. Scanning electron microscopy and thermogravimetric analysis were employed to determine morphology and thermal properties of the nanofibrillated cellulose. Further, we prepared poly(lactic acid)/nanofibrillated cellulose (PLA/NFC) composites by melt blending followed by injection molding, and subsequently characterized them using mechanical testing, size exclusion chromatography and differential scanning calorimetry. Our results showed that nanofibrillated cellulose produced in a twin-screw extruder can be used as reinforcement for poly(lactic acid). Adding only 5 wt% nanofibrillated cellulose yielded improvements in the crystallization behavior of PLA. An increase in elastic modulus was observed for all PLA/NFC composites compared to neat PLA.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718321591-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Vito Gigante, Ilaria Canesi, Patrizia Cinelli, Maria Beatrice Coltelli, Andrea Lazzeri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The present work fits into the stream of study and analysis of biobased and/or biodegradable materials, considering the need to improve their properties from a technological point of view to allow their wider use in final products. In this paper a blend of an extrusion grade poly(lactic acid) (PLA) and a percentage of a particular type of high molecular weight poly(butylene adipate-〈em〉co〈/em〉-terephathalate) (PBAT) was investigated. The blend was such that the PBAT resulted in a dispersed phase in the PLA matrix. Tensile properties, Charpy impact strength, energy absorbed by the sample during three-point bending tests, melt flow index, fracture behavior and morphology were determined to characterize PLA/PBAT blends with the aim of correlating the composition to processability and final properties. Furthermore, analytical models were applied to check if variations of the mechanical properties with an increase of the rubber content were in agreement with existing predictive theories. To evaluate the fracture behavior, starting from the Load Separation Criterion, “material key curves” of the materials, a support for a comparative study (macroscopic scale) of the plastic deformational mechanisms involved in the fracture process was achieved.〈/p〉 〈p〉The influence of the deformation rate and the temperature on the toughness of the PLA/PBAT was investigated. In particular, the ductile-to-brittle transition temperature, at a fixed test speed was estimated and a theoretical model, which is useful to predict the absorbed energy by varying the deformation rate, was proposed. This last model was validated by comparing the resulting analytical equation with the experimental data obtained through three-point bending and impact tests at different velocities.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718318743-ga1.jpg" width="289" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 7 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Yongjun Ahn, Hyungsup Kim, Seung-Yeop Kwak〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Alginate hydrogel with high stretchability and toughness was prepared using binary solvent system consisting of water and glycerol. The mechanical performance was achieved via conformational control for the alginate molecules using water/glycerol binary system. The conformational characteristics of the alginate chains in glycerol/water solution were systematically investigated by spectroscopic analysis and rheological approach. The glycerol in the solution deconstructed intra-hydrogen bonding of alginate molecules, resulting in an increase of chain flexibility and hydrodynamic volume. The flexible chains had more chance to be entangled with the neighboring chains. The inter-molecular entanglement effectively transferred the stress and hindered crack propagation. The study provides fundamental insight for the design of alginate hydrogel with high stretchability and toughness.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718316951-ga1.jpg" width="360" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Karolina Bujak, Hanna Orlikowska, Anna Sobolewska, Ewa Schab-Balcerzak, Henryk Janeczek, Stanislaw Bartkiewicz, Jolanta Konieczkowska〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To the best of our knowledge, for the first time the effect of the presence of pyridine 〈em〉vs〈/em〉 benzene structure in azochromophore on thermally driven 〈em〉cis〈/em〉-〈em〉trans〈/em〉 isomerization in a solid state is presented. The influence of the molar mass of the polymer matrix, in which the chromophores were molecularly dispersed, was revealed. The poly(etherimide) with a weight-average molecular weight within the range of 2 600–33 300 g/mol was applied as a matrix. The fragility parameter of the matrices was discussed also in the context of observed relationship between 〈em〉cis〈/em〉-〈em〉trans〈/em〉 isomerization in various matrixes. Additionally, thermal back reaction from the 〈em〉cis〈/em〉 to the 〈em〉trans〈/em〉-form of 4-[4-(6-hydroxyhexyloxy)phenylazo]pyridine and 4-[4-(6-hydroxyhexyloxy)phenylazo]benzene in DMF solution was investigated. The holographic grating recording was realized in the poly(etherimide) containing azopyridine of different content.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718325035-ga1.jpg" width="267" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Ainara Sangroniz, Leire Sangroniz, Alba Gonzalez, Antxon Santamaria, Javier del Rio, Marian Iriarte, Agustin Etxeberria〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Miscible and thermally stable blends of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) with poly(hydroxy ether of bisphenol A) (PH) are investigated to obtain membranes for packaging applications. Previously the miscibility and adequate degradability of these blends was proven, therefore this system is a good candidate for packaging applications. The crystallinity degree and the free volume, both of crucial importance in transport properties, are analysed as a function of blend composition. The transport properties to different gases and vapours are greatly reduced with the addition of PH. The blends show high elongational viscosity values, which allows expecting good film processability. Overall, this work sheds light on the factors involved in the reduction of permeability which would allow to broaden this strategy to other promising biodegradable materials.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718324248-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Jan Prokeš, Martin Varga, Martin Vrňata, Stanislav Valtera, Jaroslav Stejskal, Dušan Kopecký〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An alteration of electrical conductivity of the conducting polymers from a conducting to a non-conducting form and 〈em〉vice versa〈/em〉 is a feature of the high importance. Here, the changes in conductivity of the polypyrrole nanotubes (PPy-NT) associated with a deprotonation/reprotonation in alkaline (various concentrations of ammonium or sodium hydroxide) or acidic (1 M hydrochloric or hydrobromic acid) solutions are presented. All experiments were followed by energy dispersive X-ray spectroscopy (EDX) elemental analyses and van der Pauw conductivity measurements. Extensive measurements of conductivity of samples during 2-years' timespan have also been made in order to determine the kinetics of natural ageing of the deprotonated/reprotonated PPy-NT. EDX measurements have allowed for a deeper insight into the process of the deprotonation/reprotonation of PPy-NT, which is generally characterized by the exchange of counter-ions and by the increase in the oxygen content. Correlations among conductivities of original, deprotonated and reprotonated samples revealed the universal behaviour, which can be used for the precise prediction of the ability of PPy-NT to be reprotonated by acids. Kinetics of the degradation of PPy-NT by natural ageing is faster for deprotonated sample and, on the contrary, the reprotonation by acids had a stabilizing effect.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930254X-ga1.jpg" width="245" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Zelai Zheng, Lin Zhang, Ying Ling, Haoyu Tang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of ABA-type triblock copolymers (PImBF〈sub〉4〈/sub〉-b-PPG-b-PImBF〈sub〉4〈/sub〉) comprising of poly(propylene glycol) (PPG) as middle block and UCST polypeptide on both sides of PPG was synthesized by ring-opening polymerization of 〈em〉γ〈/em〉-chloropropyl-〈sub〉L〈/sub〉-glutamic acid-based 〈em〉N〈/em〉-carboxyanhydride (CPLG-NCA) and then side-chain modification including nucleophilic substitution of the chloro group followed by copper-mediated 1,3-dipolar cycloaddition and subsequent ion-exchange reaction. Variable-temperature UV–vis spectroscopy revealed that the upper critical solution temperature (UCST)-type cloud point temperature (T〈sub〉cp〈/sub〉) was highly dependent on both polypeptide and PPG chain length as well as polymer concentration. Increasing the polymer chain length or concentration frequently results in T〈sub〉cp〈/sub〉 increases. Noticeable hysteresis in a cooling/heating cycle was observed for all resulting triblock copolymers owing to a slow disassembly of large aggregates (d = 145 nm) in the heating cycle. Moreover, the resulting UCST triblock copolymers were used to regulate the release property of ciprofloxacin (CIP)-loaded poly(vinyl alcohol) (PVA) hydrogel. The incorporation of PImBF〈sub〉4〈/sub〉-b-PPG-b-PImBF〈sub〉4〈/sub〉 hampered the burst release of CIP at 37 °C indicating their potential toward sustained release of drug-loaded hydrogels.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉We report the preparation and UCST-type thermoresponsive properties of ABA-type triblock copolymers comprising of cationic polypeptide and poly(propylene glycol). The cloud point temperature showed molecular weight dependence owing to the formation of self-assemble structures at high temperature. The incorporation of UCST triblock copolymers hampered the burst release of ciprofloxacin-loaded poly(vinyl alcohol) hydrogels.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719302423-ga1.jpg" width="238" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Mehdi Farokhi, Fatemeh Mottaghitalab, Yousef Fatahi, Mohammad Reza Saeb, Payam Zarrintaj, Subhas C. Kundu, Ali Khademhosseini〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Regenerating chondral and osteochondral injuries is a main challenge in orthopedics. Some therapeutic strategies such as joint preservation operations, non-operative management, palliative surgery, and arthroplasty are the common clinical methods for repairing the cartilage defects. These treatments show often satisfactory as short-term outcomes and without clear long-term prospects. Over the past decade, the development of tissue engineering technologies offers a new therapeutic option to treat patients suffering from chondral lesions. Silk fibroin is a potent and advanced biomaterial for regenerating both soft and hard tissues. Fibroin scaffolds possess superior mechanical strength, suitable bioactivity, elasticity, degradability, and tailorable chemical structure. Due to the important properties as natural biomaterials, the fabrications of various types of scaffolds/matrices for regenerating the tissues like cartilage for regeneration and repairing the defects are possible. This review highlights the investigations on silk-based biomaterials for cartilage tissue engineering. The possibilities for future clinical application of silk fibroin based constructs in repairing intervertebral disk, anterior cruciate ligament, meniscus, and osteochondral defects are evaluated in detail.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303684-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Elaheh Jooybar, Mohammad J. Abdekhodaie, Abbas Mousavi, Bram Zoetebier, Pieter J. Dijkstra〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a novel biodegradable hyaluronic acid (HA) based microgel were prepared via enzymatic crosslinking of tyramine conjugated HA (HA-TA) in an inverse microemulsion. HA-TA microdroplets were crosslinked within a few seconds in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉). The high water content of the polymeric network and the inherent negative charge of the HA-TA microgels provided a suitable platform for encapsulation of cationic proteins like lysozyme and TGF-β1 growth factor. The results demonstrated that lysozyme was released, after an initial burst release, in a suitable sustained manner over a period of four weeks. Both diffusion and degradation due to microgel hydrolysis controlled the release rate. In vitro cytotoxicity of microgels using human mesenchymal stem cells revealed microgels nontoxic. This study demonstrates that the developed injectable HA-TA microgels prepared by enzymatic crosslinking are a promising vehicle for delivery of cationic proteins including some important growth factors.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718319049-ga1.jpg" width="258" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Hadi Hosseini, Mohsen Teymouri, Sajad Saboor, Alireza Khalili, Vahabodin Goodarzi, Fatemeh Poudineh Hajipoor, Hossein Ali Khonakdar, Shahrokh Shojaei, Azadeh Asefnejad, Hasan Bagheri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The fabrication of flexible, freestanding, lightweight, renewable, low cost and also the high performance of novel supercapacitors is pivotal in electronic fields. In this work, two series of ternary bio-nanocomposite flexible aerogels based on bacterial cellulose (〈em〉BC〈/em〉) as a template and containing silver nanoparticles (〈em〉AgNPs〈/em〉) and polyaniline (〈em〉PANI〈/em〉) as conductive agents facilely fabricate using an in situ method, in which Ag and PANI embedded within BC matrix as sequences. Morphology of ternary aerogels reveals the core-shell and branch-grape microstructures for 〈em〉BC/Ag/PANI〈/em〉 and 〈em〉BC/PANI/Ag〈/em〉 samples, respectively. 〈em〉BET〈/em〉 analysis exhibits that specific surface area of 〈em〉BC/Ag/PANI〈/em〉 (145 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉) is higher than 〈em〉BC/PANI/Ag〈/em〉 (130 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉) aerogel. Electrical conductivity measurements indicated that 〈em〉BC/Ag/PANI〈/em〉 (1.25 S cm〈sup〉−1〈/sup〉) possesses higher electrical conductivity than 〈em〉BC/PANI/Ag〈/em〉 (0.00693 S cm〈sup〉−1〈/sup〉) aerogels. The coexistence of PANI and Ag within BC texture, significantly altered the interfacial polarization and relaxation spectra of ternary system. A specific capacitance 357 F g〈sup〉−1〈/sup〉 at 0.5 A g〈sup〉−1〈/sup〉 associated with 83% cyclic stability over 2000 cycles is observed for 〈em〉BC/Ag/PANI〈/em〉, while 〈em〉BC/PANI/Ag〈/em〉 showed specific capacitance of 232 F g〈sup〉−1〈/sup〉 at 0.5 A g〈sup〉−1〈/sup〉 as well as 74% capacitance retention. Furthermore, in symmetrical supercapacitor setup for 〈em〉BC/Ag/PANI〈/em〉, a high energy density of 34 Wh kg〈sup〉−1〈/sup〉 at a power density of 459 Wh kg〈sup〉−1〈/sup〉 is obtained. These findings indicated that BC/Ag/PANI aerogel as a flexible and lightweight electrode could be highly used in the field of electrical energy storage.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303088-ga1.jpg" width="493" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Lihua Guo, Wenjing Liu, Kun Li, Mengmeng Sun, Wenting Sun, Liping Zhao, Guorun Jiang, Hongwei Peng, Zhe Liu, Shengyu Dai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of unsymmetrical α-diimine palladium complexes bearing low steric crowdedness on one side and bulky substituents on the other side were prepared and characterized. Activated with sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, these α-diimine Pd(II) complexes were used to catalyze ethylene oligomerization and cooligomerization with polar monomers including methyl acrylate (MA), acrylic acid (AA) and vinyltriethoxysilane (VTEoS). In ethylene oligomerization, the hyperbranched oil products were obtained with high activities (14.2–27.0 × 10〈sup〉3〈/sup〉 g mol〈sup〉−1〈/sup〉 h〈sup〉−1〈/sup〉). The remote substituent of bulky diarylmethyl moiety showed a significant effect on catalyst activity, while exhibit little variation on the molecular weight of ethylene oligomers. In ethylene-polar monomer cooligomerization, functional and hyperbranched oils were produced and polar monomer incorporations can be tuned by the perturbations of the remote substituent.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718324959-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Kateřina Nunvářová, Barbora Charvátová, Miroslav Šlouf, Soňa Hermanová, Jan Merna〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉By grafting from approach amphiphilic grafted copolymers with a hydrophobic core based on dendritic polyethylene and hydrophilic grafts of polyhydroxyethylmethacrylate (PHEMA) and polyhydroxypropylmethacrylate (PHPMA) were synthesized by tandem chain walking copolymerization and ATRP. Copolymers with molar mass 160–1400 kg/mol and ∼50–90% of hydrophilic grafts were obtained. Core-shell nanoparticles with very narrow size distribution were prepared from the copolymers by solvent displacement method. Particles diameter was efficiently regulated by molar mass of the copolymers in the range of 60–180 nm. We demonstrated that these nanoparticles can act as nanocontainers for hydrophobic Nile red dye, achieving up to 25% encapsulation efficiency. Dendritic polyethylene (dPE) nanoparticles with biocompatible polar PHEMA and PHPMA shell can find application in nanocatalysis and cargo delivery.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719300643-ga1.jpg" width="472" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 117〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 118〈/p〉 〈p〉Author(s): Camila Cubayachi, Camila Nunes Lemos, Francieli Pereira, Karina Dias, Rondinelli Donizetti Herculano, Osvaldo de Freitas, Renata F.V. Lopez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Insulin (INS) is a protein that plays a crucial role in many cellular functions, including wound healing processes. However, its topical ocular administration is a challenge, mainly because of INS degradation and low retention time, which can significantly reduce its bioavailability. The objective of this work was to develop films based on silk fibroin (SF), a natural polymer with anti-inflammatory properties, containing INS aimed at the sustained release of a bioactive INS in the eye for the treatment of corneal wounds. SF films containing 100 IU/cm〈sup〉2〈/sup〉 INS and glycerin as plasticizer were prepared by casting. They were homogeneous, transparent, permeable to water vapor, with low swelling index and high mechanical resistance. Fourier transformed infrared spectroscopy and differential scanning calorimetry analyses suggested the β-sheet/Silk II conformation of SF and the occurrence of non-covalent interactions between INS and SF. Scanning electron microscopy suggested that the INS was embedded inside the film in its native globular form. In fact, the INS released from the film maintained its native conformation, as observed by circular dichroism, in addition to conserving its biological activity 〈em〉in vivo〈/em〉, reducing the blood glycemia of Wistar rats. Sustained release, of approximately 1 IU/cm〈sup〉2〈/sup〉/h〈sup〉1/2〈/sup〉 of INS per hour, following a burst release, suggests that the film could be effective in the recovery of injured corneal epithelium, avoiding the need for the various daily administrations. Therefore, SF films demonstrated potential to transport and release INS in a sustained manner, a promising strategy for the treatment of corneal wounds.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301661-ga1.jpg" width="301" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 118〈/p〉 〈p〉Author(s): Yanjun Wang, Yuan Lei, Changlin Zhou, Bo Wu, Yuanyuan Jiang, Jingxin Lei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Incorporating reversible dynamic linkages into the polymer networks endows traditional thermosets with recyclability and reprocessability. However, the facile preparation of recyclable polymer networks with suitable stability and acceptable cost is still a challenge. Among various dynamic linkages, ionic bonds promise a rational dynamic linkage in virtue of suitable stability and facile chemical synthesis. In this study, dynamic ionic bonds were incorporated into the waterborne polyacrylate to form adaptable polymer networks. The carboxyl groups of waterborne polyacrylate provide hydrophilicity and crosslinking sites. Metal salts were added into polyacrylate emulsion to obtain crosslinked polyacrylate via solution casting process. This crosslinking strategy has improved the solvent resistance, creep resistance and tensile strength of linear polyacrylates. The effect of metal cation crosslinking on the water resistance depends on the carboxyl content of linear polyacrylate. Subsequently the mechanical property of pristine and recycled crosslinked polyacrylate was evaluated. Polyacrylate networks crosslinked by divalent metal zinc cation show superior tensile strength and recyclability. Anions of zinc salts have an obvious influence on the enhancement and recyclability of obtained polyacrylate networks. Polyacrylate crosslinked by zinc acetate shows optimal comprehensive performance and application prospect. In addition, the shape memory effect of polyacrylate crosslinked by metal salt zinc acetate was investigated. The shape fixity ratio and shape recovery ratio were 99.8% and 84.9%, respectively. This strategy promises great prospect in designing and preparing customizable high performance recyclable smart thermosets.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719309991-ga1.jpg" width="395" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Long Zhao, Xiao-Lin Wang, Li Ma, Ping-Ping Shang, Yan-Ping Huang, Zhao-Sheng Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper reported the facile method of improving the affinity of β-cyclodextrins (β-CD)-based molecularly imprinting system by using the effect of interaction of β-CD and room temperature ionic liquids (RTILs). The molecularly imprinting polymers (MIPs) of β-CD matrices were prepared with β-CD, as functional monomer, hexanethylene diisocyante as crosslinker, and using aesculin as a model molecule in a RTIL (1-butyl-3-methylimidazolium tetrafluoroborate) of porogen. The RTILs/DMSO-based MIP (or NIP) showed smaller surface areas but greater pore size than the RTILs/DMSO-free MIP (or NIP). The equilibrium adsorption experiment indicated that the imprinting factor for the β-CD-based MIP prepared with RTILs was 2.25 and 1.19 for the controlled MIP prepared without RTILs. In addition, the values of effective diffusivity (〈em〉D〈sub〉eff〈/sub〉〈/em〉) of aesculin (AN) obtained from the RTILs-assisted β-CD MIP (10〈sup〉−16〈/sup〉 cm〈sup〉2〈/sup〉/s) was about seven times smaller than those from the RTILs-free controlled β-CD MIP, although the values of free diffusivity (〈em〉D〈/em〉) of AN were all found in the order of 10〈sup〉−13〈/sup〉 cm〈sup〉2〈/sup〉/s. When used as release material, the relative bioavailability of the β-CD-based MIP prepared in RTIL displayed a markedly higher value of 399.7% than that of the commercial AN tablet. On the contrary, the β-CD-based non molecularly imprinted polymer (NIP) prepared in RTILs, β-CD-based MIP prepared in non-RTILs and β-CD-based NIP prepared in non-RTILs was only 88.6%, 179.3% and 157.0%, respectively. The results indicated that using RTIL as porogen is an effective approach to improving affinity of β-CD-based MIP.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718325436-ga1.jpg" width="311" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Guohui Zhang, Panpan Wang, Xiaoxiao Zhang, Chunhui Xiang, Lili Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hydrophobic polycaprolactone (PCL) membranes with hierarchical structure were fabricated via one-step electrospinning technique. Meanwhile, the addition of the liquid methyl silicone oil (MSO) and hydrophobic silica (SiO〈sub〉2〈/sub〉) nanoparticles in the PCL membrane were expected to improve the hydrophobicity of PCL membranes. FE-SEM images showed the microsphere-fiber interlinked hierarchical morphology of PCL/MSO/SiO〈sub〉2〈/sub〉 composite fiber. FT-IR confirmed the formation of PCL/MSO/SiO〈sub〉2〈/sub〉 composite fibers. XPS approved its hierarchical structure of the composition. By comparing with pure PCL membrane which the water contact angle (WCA) was 132.2 ± 1.2°, the WCAs of PCL/MSO and PCL/SiO〈sub〉2〈/sub〉 membrane increased to 143.3 ± 1.2° and 141.7 ± 1.9°, respectively. It was worth noting the WCA of PCL/MSO/SiO〈sub〉2〈/sub〉 composite mat could reach 151.6 ± 1.7° and the sliding angle was 7.4 ± 1.2°. The excellent surface roughness and air-pocket capacity on the hierarchical membranes were believed to contribute to the superhydrophobicity of PCL/MSO/SiO〈sub〉2〈/sub〉 membrane. The unique microsphere-fiber interlinked hierarchical structure and superhydrophobicity of membrane could provide adequate support for oil adsorption and oil-water separation. The maximum n-hexane adsorption capacity of PCL/MSO/SiO〈sub〉2〈/sub〉 membrane was 41.37 g g〈sup〉−1〈/sup〉. Separation efficiency for n-hexane-water mixture of PCL/MSO/SiO〈sub〉2〈/sub〉 membrane was as high as 99.92%. The PCL/MSO/SiO〈sub〉2〈/sub〉 hierarchical superhydrophobic mats indicate the potential applications of environmental-friendly biopolymers as separator.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718324364-ga1.jpg" width="276" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Chase B. Thompson, Sourav Chatterjee, LaShanda T.J. Korley〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Polychaete worms display a remarkable jaw structure, where a gradient in metal-ligand coordination down the length of the jaw results in a shift from hard to soft mechanics. To mimic these gradient structures, a Zn-coordinated supramolecular polymer is crosslinked into a covalent matrix to afford supramolecular semi-interpenetrating networks (SIPNs). These SIPN materials exhibit improved mechanics with a lower supramolecular content (30 wt%), allowing for energy dissipation through cavitation to increase material toughness. The shift in mechanical behavior is further attributed to the morphology, where the size of the phase-separated droplets and nature of the continuous phase in these SIPNs contributes to the material mechanics. Furthermore, chemical gradients are applied to these systems through exposure to a competitive ligand, offering control over the localization of supramolecular interactions. These materials offer a framework to mediate mechanics while maintaining the ability to program gradient supramolecular interactions.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718325370-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Guzel K. Abilova, Daulet B. Kaldybekov, Elvira K. Ozhmukhametova, Aisulu Zh. Saimova, Diara S. Kazybayeva, Galiya S. Irmukhametova, Vitaliy V. Khutoryanskiy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Polymeric films were prepared based on chitosan and its blends with poly(2-ethyl-2-oxazoline) by casting from aqueous solutions. These materials were characterised using a number of physicochemical techniques, including Fourier-transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, wide angle x-ray diffraction, tensile testing and scanning electron microscopy. All these studies indicate that there is a weak intermacromolecular hydrogen bonding between these polymers, which facilitates their complete miscibility in solid state. These films were formulated with sodium fluorescein as a model drug and were evaluated for their potential application in ocular drug delivery both 〈em〉in vitro〈/em〉 and 〈em〉in vivo〈/em〉. It was established that the films are biocompatible and mucoadhesive; they are capable of providing a sustained drug release when administered topically on the cornea.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303313-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Diederik W.R. Balkenende, Sally M. Winkler, Phillip B. Messersmith〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Medical adhesives that are strong, easy to apply and biocompatible are promising alternatives to sutures and staples in a large variety of surgical and clinical procedures. Despite progress in the development and regulatory approval of adhesives for use in the clinic, adhesion to wet tissue remains challenging. Marine organisms have evolved a diverse set of highly effective wet adhesive approaches that have inspired the design of new medical adhesives. Here we provide an overview of selected marine animals and their chemical and physical adhesion strategies, the state of clinical translation of adhesives inspired by these organisms, and target applications where marine-inspired adhesives can have a significant impact. We will focus on medical adhesive polymers inspired by mussels, sandcastle worms, and cephalopods, emphasize the history of bioinspired medical adhesives from the peer reviewed and patent literature, and explore future directions including overlooked sources of bioinspiration and materials that exploit multiple bioinspired strategies.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719300588-ga1.jpg" width="446" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Ernesto Tinajero-Díaz, Antxon Martínez de Ilarduya, Sebastián Muñoz-Guerra〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Diblock copolymers (PPDLx-〈em〉b〈/em〉-pPAAy) were prepared from ω-pentadecalactone and 〈span〉l〈/span〉-glutamic acid or 〈span〉l〈/span〉-lysine amino acids by ring opening polymerization initiated by amino groups. Telechelic amino-ended poly(ω-pentadecalactone) with a length of 15–20 repeating units was firstly synthesized by enzymatic polymerization by means of CALB and then used as macroinitiator for the polymerization of the 〈em〉N〈/em〉-carboxyanhydrides of the two α-amino acids conveniently protected as benzyl and 〈sup〉ε〈/sup〉〈em〉N〈/em〉-carbobenzoxy derivatives, respectively. The molecular weight of the polypeptide block was accurately controlled by adjusting the amino acid/macroinitiator ratio used in the feed. Copolymers with 〈em〉M〈sub〉n〈/sub〉〈/em〉 ranging between ∼5000 and ∼40,000 g·mol〈sup〉−1〈/sup〉 and varying ester/peptide ratio were obtained and characterized in detail by GPC and NMR spectroscopy. The thermal properties of these copolymers were evaluated by TGA and DSC, and their structure in the solid-state including their response to heating, were examined by FTIR and XRD at variable temperature. It was shown that the polypentadecalactone segment was crystallized for all compositions and that the polypeptide counterpart adopted a two-dimensional hexagonal packing of α-helices at temperatures above melting of the polyester block. SAXS revealed the presence of a biphasic nanostructure with a repeating distance of 27 nm for the case of glutamic-based copolymers. It was demonstrated that both glutamic and lysine-based PPDL〈sub〉x〈/sub〉-〈em〉b〈/em〉-pPAA〈sub〉y〈/sub〉 copolymers could self-assemble in well-shaped nanospheres with a diameter in the ∼200–400 nm range and a negative zeta-potential.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303283-ga1.jpg" width="475" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Sébastien Livi, Luanda C. Lins, Larissa B. Capeletti, Charline Chardin, Nour Halawani, Jérôme Baudoux, Mateus B. Cardoso〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The design of new highly effective polymer materials as active surfaces or coatings against microorganisms such as Escherichia coli (〈em〉E. coli〈/em〉) is a major challenge for public health. In the present work, novel imidazolium ionic liquid monomers (ILMs) having a similar structure of conventional Bisphenol A diglycidyl ether epoxy prepolymer (DGEBA) have been designed without requiring to the use of toxic and carcinogenic compounds 〈em〉i.e.〈/em〉 Bisphenol A and epichlorohydrin. Then, a facile and efficient polyaddition reaction-based polymerization via a one step process was used in order to prepare unprecedented antibacterial epoxy-amine networks. The ultimate role of the monomers architecture on the epoxy conversion as well as on the reactivity of the epoxy-functionalized imidazolium ionic liquid monomers with an aliphatic amine (D-230) was investigated while the average molecular weight between crosslinks (Mc) and the relaxation temperature of the resulting networks were determined. Thus, new epoxy thermosets with an excellent thermal stability, high hydrophobic behavior and good storage modulus at room temperature were produced. Finally, antimicrobial tests against 〈em〉E. coli〈/em〉 were performed for the first time on these new cross-linked epoxy networks leading to a very strong inhibition of 〈em〉E. coli〈/em〉 biofilm formation (−95%).〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉SEM micrographs of active surfaces against microorganisms such as Escherichia coli (〈em〉E. coli〈/em〉) composed of conventional epoxy-amine (DGEBA/D230 (a and e)) and epoxy-amine networks based on Ionic Liquid Monomer (ILM) 〈em〉i.e.〈/em〉 ILM-1 (b and f), ILM-2 (c and g) and ILM-3 (d and h)〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303829-ga1.jpg" width="403" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Hanna P. Steinmetz, Safra Rudnick-Glick, Michal Natan, Ehud Banin, Shlomo Margel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bacterial resistance to antibiotics is a major challenge in health research. A recent approach to combat this resistance is by interfering with vital bacterial functional systems. Calcium ions play an important role in bacterial functions such as bacterial cell stability, regulation of virulence genes, and in the function of various intracellular proteins. Bisphosphonate compounds have a high affinity for calcium ions and the antibacterial activity of bisphosphonates in combination with antibiotics has been recently studied. However, the antibacterial behavior of the bisphosphonate group itself has hardly been investigated. New cross-linked poly(styryl bisphosphonate) nanoparticles (poly(StBP) NPs) with a narrow size distribution and high yield were engineered using a dispersion copolymerization of styryl bisphosphonate monomer with the cross-linking monomer triethylene glycol diacrylate and the primary amino monomer N-(3-aminopropyl) methacrylamide hydrochloride. The diameter and size distribution were controlled by changing various polymerization parameters. Fluorescent poly(StBP) NPs were prepared by covalent binding of the primary amino groups on the poly(StBP) NPs surface to the dye BODIPY-FL-NHS ester; these NPs demonstrated a strong affinity for calcium ions. Antibacterial properties of optimal poly(StBP) NPs were studied compared to control NPs, which contain a methoxy group instead the bisphosphonate functional group. Unlike the control NPs, the poly(StBP) NPs demonstrated a significant antibacterial activity for both Gram negative (〈em〉Escherichia coli〈/em〉 and 〈em〉Pseudomonas aeruginosa〈/em〉) and Gram-positive (〈em〉Staphylococcus aureus〈/em〉 and 〈em〉Bacillius subtilis〈/em〉) bacteria.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Synthesis of the novel poly(styryl bisphosphonate) nanoparticles which demonstrate a significant antibacterial activity for both Gram negative and Gram-positive bacteria.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718322936-ga1.jpg" width="462" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 118〈/p〉 〈p〉Author(s): Korneliusz Wolski, Stefan Cichosz, Anna Masek〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this research lignocellulosic waste is utilized as a filler in ethylene-norbornene copolymer (Topas®) matrix. To improve the interface properties between the filler and polymer matrix, lignocellulose was chemically hydrophobized with two coupling agents, namely: vinyltrimethoxysilane (VTMS) and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPS). Prepared composite samples have been investigated for their thermal and mechanical properties, as well as structure changes. Fourier-transform infrared spectroscopy (FT-IR) analysis revealed that possible bonds recombination within the composite structure may occur – intensity changes in 1100–1000 cm〈sup〉−1〈/sup〉 region (CO〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CO moieties) and 1300–1200 cm〈sup〉−1〈/sup〉 (〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉CH〈sub〉3〈/sub〉, C〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/dbnd"〉O, C〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/dbnd"〉C bonds). This phenomenon contributed to the observed improvement of composite storage modulus values and performance. Modified lignocellulosic fibres were investigated to assess properties changes which could confirm the silanization occurrence, e.g., increase in thermal stability, hydrodynamic radii enlargement. This research reports the most relevant advances in the field of chemical surface modification of lignocellulose fibres recently achieved by our group.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719307876-ga1.jpg" width="468" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Xiaoyun Liu, Yanling Ding, Jing Liu, Shaoliang Lin, Qixin Zhuang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fluorine-containing amphophilic polymers, as well as star polymers, have shown extremely abundant self-assembled morphologies because of microphase separation within the assemblies. Taking advantage of these characteristics, we prepared a series of ABC miktoarm star terpolymers with poly(ethylene glycol) (PEG) as a hydrophilic block, as well as poly(2-ethylhexylmethacrylate) (PEHMA) as a hydrophobic chain. Poly(1H,1H,5H-octafluoropentylmethacrylate) (POFPMA) was chosen as the third segment of terpolymers because of its super-hydrophobic/oleophobic characteristics. The terpolymers were synthesised via atom transfer radical polymerisation (ATRP), single electron transfer living radical polymerisation (SET-LRP) and azide-alkyne Huisgen cycloaddition (click reaction). Herein, we investigated the self-assembled behaviours of nanoaggregates formed by varying the length of POFPMA and PEHMA chains of the terpolymers in aqueous solution. The tunable miktoarm star polymer favoured the transformation of nanoassemblies, from patchy spherical micelles to patchy spherical aggregates, spherical micelles, egg-like micelles, segmented-worm micelles, shuttle-like micelles and vesicles. Interestingly, special discontinuous aggregations arranged into lines were observed, which has been seldom found before. The independent control of both of the hydrophobic parameters of terpolymers enhanced the nanostructures of polymeric assemblies of ABC miktoarm terpolymers, providing a reliable method to explore the compartmentalisation behaviours of soft matter assemblies.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719305506-ga1.jpg" width="445" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Hoan Minh Tran, Le-Thu T. Nguyen, Tam Huu Nguyen, Ha Lac Nguyen, Nam T.S. Phan, Geng Zhang, Tsutomu Yokozawa, Hai Le Tran, Phong Thanh Mai, Ha Tran Nguyen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉While several strategies have been developed in the literature to obtain rod-coil graft copolymers composed of regioregular poly(3-hexyl thiophene) (P3HT), our contribution in this field consists of a convenient and versatile way to obtain a copolymer with a coil polymethacrylate backbone grafted with P3HT rod chains by a combination of the thiol-maleimide chemistry and MOF-catalyzed photoinitiated atom transfer radical polymerization (ATRP) method. Well-defined synthesis of the P3HT-graft copolymer was described, and its structure, morphology and properties were characterized by proton nuclear magnetic resonance, gel permeation chromatography, Fourier transform infrared, UV–vis and photoluminescence spectroscopy, differential scanning calorimetry and atomic force microscopy.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719304367-ga1.jpg" width="286" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Samadhan S. Nagane, Savita Verma, Bhausaheb V. Tawade, Prakash S. Sane, Sushilkumar A. Dhanmane, Prakash P. Wadgaonkar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A partially bio-based bisphenol containing pendant azido group 〈em〉viz.,〈/em〉 4,4′-(5-azidopentane-2,2-diyl) diphenol (AZBPA) was synthesized starting from 4,4′-bis (4-hydroxyphenyl) pentanoic acid. AZBPA was reacted with isophthaloyl chloride (IPC), terephthaloyl chloride (TPC) and a mixture of IPC/TPC (50:50 mol%) by phase transfer-catalyzed interfacial polycondensation route to obtain aromatic polyesters containing pendant azido groups. Copolyesters containing pendant azido groups were also synthesized by polycondensation of different molar proportions of AZBPA and commercially available 4,4′-(1-phenylethane-1,1-diyl) diphenol (BPA-AP) with IPC. Inherent viscosities and number average molecular weights of (co)polyesters were in the range 0.85–1.64 dL/g and 58,900–190,400, respectively, indicating the formation of reasonably high molecular weight polymers. Tough, transparent, and flexible films could be cast from chloroform solutions of these polyesters. X-Ray diffraction analysis showed that (co)polyesters were amorphous in nature. (Co)polyesters were characterized using FT-IR, 〈sup〉1〈/sup〉H NMR spectroscopy, XRD, TGA and DSC analysis. The chemical modification of a representative copolyester containing pendant azido groups was carried out quantitatively using copper-catalyzed azide-alkyne cycloaddition (CuAAC) with two alkynes 〈em〉viz.,〈/em〉 phenyl acetylene (PA) and ethynyl-4-nitrobenzene (ENB). Additionally, (co)polyesters containing pendant azido groups were thermally cross-linked (170 °C/12 h) leading to the formation of network structures based on azide to nitrene decomposition and subsequent reactions on polyester backbone. The selected cross-linked polyesters were characterized by stress-strain measurements. The cross-linked polymers exhibited higher tensile strength and Young’s modulus and lower % elongation at break compared to corresponding pristine polyesters containing pendant azido groups.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719304525-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Yan Zhang, Shumin Zhou, Xiangchen Fang, Xin Zhou, Jingya Wang, Fudong Bai, Shaozhong Peng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, a renewable and flexible UV-shielding biocomposite film was obtained by poly(butylene succinate) (PBS) and lignin. A strategy of reactive interfacial compatibilization was developed in order to improve the miscibility of lignin with PBS. Firstly, lignin was modified by maleic anhydride, and then the reactive plasticizer triethy citrate (TEC) was employed as a bridge to reinforce the interaction of lignin with PBS. The elongation at break and the Young’s modulus of the films were evaluated at a maximum of 208% and 129 MPa respectively at the lignin content of 20% and TEC content of 5%, indicating the excellent enhanced flexibility. The miscibility of the lignin was rationalized through the analysis of SEM, DSC, and FT-IR. Exceptionally, the films could block against 100% UV light and degrade absolutely in different compositions. Conclusively, the strategy opens up novel approaches to expand the accessibility of lignin to renewable bioplastics.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301818-ga1.jpg" width="387" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 117〈/p〉 〈p〉Author(s): Giovani Pavoski, Daniel Luiz Stamm Baldisserotto, Thuany Maraschin, Luiz Fernando Wentz Brum, Cristiane dos Santos, João Henrique Zimnoch dos Santos, Adriano Brandelli, Griselda Barrera Galland〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Silver nanoparticles (AgNPs) were synthesized via three routes where silver was reduced by either citric acid (R1), glucose (R2) or glycerol (R3), and were stabilized with (3-aminopropyl) triethoxysilane (APTES). All nanoparticles were encapsulated in silica by the sol-gel process (SiAgE). Structural, textural, morphological and antibacterial properties of SiAgE were determined by: SEM, TGA, XRD, UV–VIS, FT-IR, BET, SAXS and disc diffusion. These SiAgE had antimicrobial properties, and they were used in ethylene polymerization using the Cp〈sub〉2〈/sub〉ZrCl〈sub〉2〈/sub〉/MAO catalytic system. The catalytic activities were high, and the percentages by weight of the fillers ranged from 1.1 to 1.6 wt%. The antibacterial properties of the nanocomposite films were studied by two tests: disc diffusion and the Parallel Streak method. The polyethylene (PE)/SiAgE nanocomposites inhibited the proliferation of 〈em〉Staphylococcus aureus〈/em〉 (Gram positive) and 〈em〉Escherichia coli〈/em〉 (Gram negative) bacteria in contact with the films, thus showing potential to be used as active packages in medicine.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930480X-ga1.jpg" width="274" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 117〈/p〉 〈p〉Author(s): Shengzhi Zou, Xinru Wang, Suna Fan, Jiaming Zhang, Huili Shao, Yaopeng Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Antheraea pernyi〈/em〉 silk, which is from a kind of non-mulberry silkworm produced in China, has better mechanical properties and cytocompatibility than the extensively studied silk from mulberry silkworm 〈em〉(Bombyx mori)〈/em〉. In this work, the regenerated 〈em〉Antheraea pernyi〈/em〉 silk fibroin (RASF) scaffolds were prepared from RASF aqueous solutions with different concentrations by a freeze-drying method. The morphologies, structures and properties of the obtained RASF scaffolds were investigated. It was found that with the decrease of RASF solution concentration and the increase of freezing temperature, the porosity of the scaffold increased while its apparent density decreased. The micro-morphology of the scaffold from the 1 wt% RASF solution was irregular. When the solution concentration was increased to the range of 4–13 wt%, the micro-morphologies of the obtained scaffolds mainly showed lamellar-like structure. And with the increase of solution concentration, the lamellar gap of the scaffold decreased while the lamellar thickness of the scaffold increased. However, with the further increase of solution concentration, the morphology of scaffold could gradually transfer into porous structure. In addition, the scaffold micro-morphology could be also affected by freezing temperature. Moreover, with the increase of RASF solution concentration or (and) the decrease of freezing temperature, the obtained scaffold had higher content of β-sheet conformation and higher crystallinity, which could improve its mechanical properties. It was further found that the swelling ratio and degradation rate of RASF scaffold prepared for tissue engineering increased with the decrease of solution concentration. The results of MTT indicated that the obtained RASF scaffold had no cytotoxicity. Moreover, the results of field emission scanning electron microscopy and laser confocal scanning microscopy revealed that the viability, cytocompatibility and migration ability of Schwann cells cultured on RASF scaffold were much better than those cultured on regenerated 〈em〉Bombyx mori〈/em〉 silk fibroin (RBSF) scaffold. The RASF scaffold prepared in this work may have great potential applications in the area of nerve tissue engineering.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718321244-ga1.jpg" width="285" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 118〈/p〉 〈p〉Author(s): Daniel A. Palacio, Bruno F. Urbano, Manuel Palencia, Bernabé L. Rivas〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The objective of this work was to study the effect of the loading of monomers (cationic, anionic and ampholytes) in the preparation of polyelectrolyte hydrogels (PEHG) based on alkylated vinylated chitosan, in order to improve the understanding of the effect of ionic monomers on the polymerization of alkylated vinyl chitosan to obtain PEHGs. To achieve this, sequential synthesis of PEHGs was carried out starting from chitosan, glycidyl methacrylate (GMA) and ionic monomers: sodium 4-styrenesulfonate, [3-(methacryloylamino)propyl]dimethyl(3-sulfopropyl)ammonium hydroxide and 4-(vinylbenzyl)trimethylammonium chloride. The stages of synthesis were (a) chemical modification of the chitosan with 〈em〉N〈/em〉-(3-chloro-2-hydroxypropyl)-trimethylammonium chloride as an alkylating agent to obtain chitosan with positive charges, (b) insertion of vinyl side groups by opening the epoxide ring at pH 3.8 using GMA and (c) 〈em〉in situ〈/em〉 polymerization of vinyl monomers in a polyelectrolyte aqueous solution (ACh-vinyl solution). Characterizations of the intermediate and PEHGs were performed. It was concluded that the different solution processes occurring in the reactor can be explained by counterion condensation theory in conjunction with Gibbs-Donnan equilibrium. The water absorption capacities of PEHGs were 144.6, 42.7, and 92.5 g H〈sub〉2〈/sub〉O/g of dried HG for cationic, ampholyte, and anionic hydrogels, respectively.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303842-ga1.jpg" width="326" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 20 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Hao Zhang, Yilin Dong, Keke Huang, Jingsheng Liu, Bo Dong, Feng Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This report describes the synthesis of a series of magnesium complexes bearing sterically congested phenoxide ligands and their catalytic performances in initiating immortal Ring Opening Polymerization of 〈em〉ε〈/em〉-caprolactone and 〈em〉rac〈/em〉-lactide. The magnesium complexes 〈strong〉Mg1〈/strong〉-〈strong〉Mg3〈/strong〉 were obtained in high yields, by treating bulky phenoxide ligands with half equivalents of Mg(〈em〉n-〈/em〉Bu)〈sub〉2〈/sub〉 in THF (〈strong〉Mg1〈/strong〉: Mg(O-2,6-Ph〈sub〉2〈/sub〉CH-C〈sub〉6〈/sub〉H〈sub〉2〈/sub〉-4-Me)〈sub〉2〈/sub〉(THF)〈sub〉2〈/sub〉; 〈strong〉Mg2〈/strong〉: Mg(O-2,6-Ph〈sub〉2〈/sub〉CH-C〈sub〉6〈/sub〉H〈sub〉2〈/sub〉-4-OMe)〈sub〉2〈/sub〉(THF)〈sub〉2〈/sub〉; 〈strong〉Mg3〈/strong〉: Mg(O-2-Ph〈sub〉2〈/sub〉CH-C〈sub〉6〈/sub〉H〈sub〉2〈/sub〉-4,6-〈em〉〈sup〉t〈/sup〉〈/em〉Bu〈sub〉2〈/sub〉)〈sub〉2〈/sub〉(THF)〈sub〉2〈/sub〉), and well-characterized by NMR spectrum analysis. The molecular structures of 〈strong〉Mg2〈/strong〉, 〈strong〉Mg3〈/strong〉 were further determined by single crystal X-ray diffractions. In combination with excess of benzhydrol, these complexes could catalyze immortal Ring Opening Polymerization (ROP) of 〈em〉ε〈/em〉-caprolactone and 〈em〉rac〈/em〉-lactide, and benzhydrol served as co-initiator and chain transfer agents simultaneously, which afforded polymer esters with well-controlled molecular weights and narrow molecular weight distributions. End-functionalized polyester could be also accessed if functionalized benzhydrols were employed as chain transfer agents.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719304653-ga1.jpg" width="480" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 117〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 118〈/p〉 〈p〉Author(s): Thi Tuong Vy Phan, Van Tu Nguyen, Seok-Hwan Ahn, Junghwan Oh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the large near-infrared (NIR) absorption and the high NIR photothermal effect, gold nanostar (AuNS) has potential application in the biomedical field. However, the complicated synthesis process with toxic precursors is a serious issue for its practice. Herein, we reported a novel green synthesis procedure using chitosan polymer from marine and vitamin C for the preparation of AuNS. For the first time, chitosan was used as a stabilizer, shape-directing, and size-controllable agents for the preparation of AuNS. The size of the obtained AuNS ranged from 111 to 225 nm with different λ〈sub〉max〈/sub〉. The AuNS exhibited near-infrared absorption with the excellent biocompatibility toward non-cancerous cell line (MG63) and cancerous cell line (MDA-MB-231). The 〈em〉in vitro〈/em〉 photothermal therapy and photoacoustic imaging with assisting of obtained AuNS were also proved the high efficiency of these nanoparticles.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719305828-ga1.jpg" width="391" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 114〈/p〉 〈p〉Author(s): Henry Shere, Paul McKeown, Mary F. Mahon, Matthew D. Jones〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of monopyrrolidine metal complexes have been prepared with the aim of elucidating structure-to-activity relationships for the ROP of lactide. Complexes of Li(I), Mg(II), Zn(II) and Zr(IV) were synthesised and fully characterised. Structural comparisons are made to the bipyrrolidine analogues. These monopyrrolidine complexes were found to be active towards the ROP of lactide under both solution and melt conditions. The zirconium complexes were found to have reduced and opposing stereocontrol compared to the bipyrrolidine analogues. The zinc and magnesium complexes demonstrated good activity and control under immortal polymerisation conditions.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719300722-ga1.jpg" width="279" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 27 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Jéssica Ribeiro Oliveira, Lloyd Ryan Viana Kotzebue, Selma Elaine Mazzetto, Diego Lomonaco〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work is described the use of Cashew Nutshell Liquid (CNSL) and the lignin-derivate catechol as widely available renewable starting materials for the synthesis of BPA-free benzoxazines. The bio-based resins were obtained through an efficient eco-friendly method using microwave-irradiation as a heating source, producing resins with good yields. After characterization by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance Spectroscopy (〈sup〉1〈/sup〉H and 〈sup〉13〈/sup〉C NMR) and differential scanning calorimetry (DSC), these resins were combined in different ratios and then thermally (co)polymerized to obtain fully bio-based polybenzoxazines. These thermosets were studied by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and three-point flexural test, which showed elevated char yield (up to 40%) and good mechanical properties (〈em〉T〈/em〉〈sub〉g〈/sub〉 above 200˚C). Sustainable metrics, E factor and Atom Economy, were also applied for the synthesis of the bio-based monomers demonstrating the greenness of this process and suggesting that these materials can be considered interesting high-performance alternatives to substitute BPA-based polybenzoxazines.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301685-ga1.jpg" width="356" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Mohsen Setayeshmehr, Ebrahim Esfandiari, Batool Hashemibeni, Amir Hossein Tavakoli, Mohammad Rafieinia, Ali Samadikuchaksaraei, Lorenzo Moroni, Mohammad Taghi Joghataei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Porous scaffolds derived from native cartilage matrix along with autologous cells could be an effective tool for cartilage tissue engineering (CTE). Recently, it was shown that scaffolds based on cartilage extra cellular matrix (ECM) can induce chondrogenesis of human adipose-derived mesenchymal stromal cells (ASCs) without using exogenous growth factors. However, lack of mechanical properties, rapid biodegradation, and contraction of these scaffolds in culture limit further applications. The present study investigated the fabrication of novel scaffolds based on devitalized costal cartilage matrix (DCM) and poly vinyl alcohol (PVA), using genipin as a natural crosslinker. For this purpose, PVA was modified to expose amine groups (PVA-A), which crosslinked with DCM powder via the lowest genipin percentage of 0.04 % (wt/wt). The crosslinked scaffolds were characterized by different techniques including porosity percentage, pore size, mechanical properties, crosslinking density, and swelling. ASCs were seeded on the scaffolds using fibrin hydrogel. Gene expression measurements, biochemical assays and histological staining confirmed that ASC-seeded constructs cultured in the chondrogenic medium can express cartilage-specific genes and synthesize cartilage-related macromolecules. In the presence of TGF-β3 the constructs exhibited significant expression of these markers compared to the control medium. These findings suggest that [genipin-crosslinked DCM-PVA-A/ fibrin] can be considered as an appealing hybrid scaffold for CTE applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303866-ga1.jpg" width="394" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 24 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Agueda Sonseca, Andrew McClain, Judit E. Puskas, Miroslawa El Fray〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of segmented bio-copolyesters based on crystallizable hard segments of poly(butylene succinate) (PBS) and fully bio-based dilinoleic diol (DLAOH), creating dilinoleic succinate (DLS) soft segments, were prepared by enzymatically catalyzed polycondensation. The kinetic studies performed with 〈sup〉1〈/sup〉H NMR and SEC have proved incorporation of highly hydrophobic DLAOH into the polymer backbone. We found that the efficacy of DLAOH incorporation was limited by the catalytic pocket size of the enzyme and its hydrophobic nature favouring the formation of long PBS sequences, especially at the early synthesis stages and having an effect on final content of soft segments compared to feed ratio. Based on quantitative 〈sup〉13〈/sup〉C-NMR analysis we found that copolymers had 〈em〉R-〈/em〉values lower than 1, that is low degree of randomness. Differential scanning calorimetry (DSC) revealed changes in degree of crystallinity and the presence of a phase mixed system.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719302800-ga1.jpg" width="350" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 24 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Alojz Šoltýs, Viktor Hronský, Natália Šmídová, Dušan Olčák, František Ivanič, Ivan Chodák〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈sup〉1〈/sup〉H and 〈sup〉13〈/sup〉C NMR spectroscopy was used for the study of corn starch plasticized with urea and/or glycerol. The information on the interactions between plasticizers and starch macromolecules as well as the arrangement of starch macromolecules depending on the storage time (from 1 day to 52 weeks), were obtained from the broad-line and magic-angle spinning 〈sup〉1〈/sup〉H NMR spectra measured at 22 °C and within the range from 30 to 140 °C and the cross-polarization magic-angle spinning (CP MAS) 〈sup〉13〈/sup〉C NMR spectra measured at 30 °C. The 〈sup〉1〈/sup〉H chemical shifts for the groups of the plasticizer molecules enabled characterization of the interactions between urea and glycerol molecules in starch plasticized with a mixture of urea and glycerol. With increasing temperature, the signal related to water molecules gradually vanished due to water evaporation, and resolved 〈sup〉1〈/sup〉H peaks associated with starch macromolecules were detected above 100 °C. The free water amount in the thermoplastic starch samples was also estimated using MAS 〈sup〉1〈/sup〉H NMR spectra. Formation of double helices due to sample ageing was observed through the CP MAS 〈sup〉13〈/sup〉C NMR spectra.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718317865-ga1.jpg" width="244" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Kingshuk Dutta, Dipak Rana〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Contamination of water with pollutants that are toxic and/or carcinogenic has led to serious and irreversible consequences to the quality and safety of the water that we consume on a daily basis. This has led to extensive research worldwide to find immediate and effective solutions to this problem. One such practically efficient solution is the treatment of contaminated water for the removal of added contaminants. Among the materials used for water treatment, adsorbents and photocatalysts have been used extensively since they are easy to fabricate, functionalize and use, and they demonstrate high removal efficiencies. Very recently, polythiophene and its derivatives, as well as modified composites of polythiophene and its derivatives, have emerged as extremely promising adsorbent and photocatalyst materials. These materials possess high charge density, surface area and a number of sites to interact and adsorb pollutants. Herein, the research progress achieved so far regarding the fabrication and application of these polythiophene-based adsorbents/photocatalysts toward water purification has been summarized.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718325254-ga1.jpg" width="399" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): J.H. Lopes, C.G. França, M.M. Beppu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The ternary membrane-forming system based on the silk fibroin (SF), glycerol (GLY) and sol-gel precursor of 58S bioactive glass (BG) was studied for the preparation of novel and multifunctional hybrid membranes. The morphology of membranes was observed by scanning electron microscopy (SEM) and spectral imaging, by X-ray mapping technique, were performed in order to investigate the chemical homogeneity of elements. The results show that there is a critical limit for the concentration of GLY and BG for formation of flexible membranes and without a phase separation. XRD and FTIR data showed that the GLY and BG in the silk matrix modifies the short- and intermediate-range order resulting in changes in the silk conformation, i.e., SF molecules are gradually transformed from random coils toward more stable structures – Silk I and Silk II (β-sheets). The solubility study showed that the hybrid membranes have an excellent chemical stability, confirming that the incorporation of inorganic species in the matrix allowed the preparation of novel well-controlled water-soluble membranes. The release profiles of Ca, P and Si confirmed ability of hybrid membranes to deliver controlled inorganic species, which in critical concentration, control the gene expression of osteoblasts and influences cell metabolism and function.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718325400-ga1.jpg" width="277" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Tzu-Chun Tseng, Shiao-Wei Kuo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We synthesized two miscible disordered diblock copolymers, poly(methyl methacrylate–〈em〉b〈/em〉–vinylphenol) (PMMA-〈em〉b〈/em〉-PVPh) and poly(4-vinylpyridine–〈em〉b〈/em〉–ethylene oxide) (P4VP-〈em〉b〈/em〉-PEO), through anionic living and reversible addition fragmentation chain transfer polymerizations, respectively; together, these polymers contained one hydrogen bond donor (PVPh) and three hydrogen bond acceptors (P4VP, PEO, PMMA). The inter-association equilibrium constants (〈em〉K〈/em〉〈sub〉A〈/sub〉) for the three different hydrogen bonded pairs followed the order PVPh/P4VP (〈em〉K〈/em〉〈sub〉A〈/sub〉 = 1200) 〉 PVPh/PEO (〈em〉K〈/em〉〈sub〉A〈/sub〉 = 280) 〉 PVPh/PMMA (〈em〉K〈/em〉〈sub〉A〈/sub〉 = 47.1), suggesting that the PVPh units prefer to hydrogen bond with P4VP block, rather than PEO and PMMA blocks. Nevertheless, the excluded PMMA and PEO segments experienced weak intermolecular dipole–dipole interactions, such that the PMMA-〈em〉b〈/em〉-PVPh/P4VP-〈em〉b〈/em〉-PEO blends exhibited two-phase behavior, forming miscible PVPh/P4VP and PMMA/PEO phases, as evidenced using transmission electron microscopy.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301363-ga1.jpg" width="256" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Xiaocen Lu, Congguang Zheng, Huiqi Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecularly imprinted polymers (MIPs) compatible with complex biological samples hold much promise in many bioanalytical and biomedical applications and development of new strategies for obtaining such advanced synthetic receptors is thus of high interest. Herein, a facile and efficient new approach is presented for the preparation of MIP microspheres capable of selectively recognizing small organic analyte in the complex biological sample, which involves the simple surface modification of MIP particles bearing polyethylene glycol (PEG) brushes with 〈em〉α〈/em〉-cyclodextrin (〈em〉α〈/em〉-CD). The proof-of-principle was demonstrated by the first synthesis of propranolol-imprinted polymer microspheres bearing PEG brushes of different molecular weights (〈em〉M〈/em〉〈sub〉n〈/sub〉 = 2000 and 5000) via our previously developed reversible addition-fragmentation chain transfer (RAFT) coupling chemistry, their supramolecular inclusion complexation with 〈em〉α〈/em〉-CD, and subsequent chemical crosslinking. The chain length of the surface-grafted PEG brushes showed much influence on the water-compatibility of MIPs. Whereas the MIP particles bearing PEG brushes of 〈em〉M〈/em〉〈sub〉n〈/sub〉 = 2000 hardly showed specific template bindings in both pure water and pure milk, those bearing PEG brushes of 〈em〉M〈/em〉〈sub〉n〈/sub〉 = 5000 exhibited moderate specific template bindings in pure water. Nevertheless, the latter MIP particles still failed to show enough specific template bindings in pure milk. The inclusion of 〈em〉α〈/em〉-CD onto PEG brushes proved to largely enhance the surface hydrophilicity of MIPs and lead to their much improved water-compatibility. In particular, the MIP microspheres bearing 〈em〉α〈/em〉-CD-modified PEG brushes of 〈em〉M〈/em〉〈sub〉n〈/sub〉 = 5000 showed excellent specific template bindings in both pure water and pure milk. The above strategy not only paves the way for efficiently preparing biological sample-compatible MIPs, but also opens the possibility of generating many other advanced biomaterials with high antifouling properties.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718320792-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 114〈/p〉 〈p〉Author(s): Fehaid Alsubaie, Evelina Liarou, Vasiliki Nikolaou, Paul Wilson, David M. Haddleton〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Aqueous Cu-RDRP was utilized for the rapid synthesis of poly(〈em〉N〈/em〉-isopropyl acrylamide)-〈em〉block〈/em〉-poly(2-hydroxyethyl acrylamide) (PNiPAm〈sub〉x〈/sub〉-〈em〉b〈/em〉-PHEAAm〈sub〉y〈/sub〉) copolymers with thermo-responsive viscosity. The pre-disproportionation of Cu(I)Br in the presence of an aliphatic tertiary amine (Me〈sub〉6〈/sub〉Tren) in water generated 〈em〉nascent〈/em〉 Cu(0) and [Cu(II)] complexes and facilitated the rapid synthesis of a series of (block) copolymers with low dispersity values (1.08 〈 〈em〉Đ〈/em〉 〈 1.22) and control over the molecular weight (〈em〉M〈/em〉〈sub〉n,SEC〈/sub〉 ∼ 30,000). The control over the polymerization enabled the design of a series of block copolymers with precision over the segment ratio, which exhibit different thermo-responsive aggregation. Thermal analysis, viscometry and fluorescence measurements gave insights on the effect of composition and temperature alterations rendering the synthesized polymers potential candidates for temperature-dependent applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303143-ga1.jpg" width="360" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 26 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Beibei Wang, Xiaozhen Xiao, Yuhuan Zhang, Liqiong Liao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, high strength dual-crosslinked hydrogels with photo-switchable color changing behavior were designed and fabricated. In the mixture solution of α-cyclodextrin (α-CD), α-cyclodextrin-spiropyran (α-CD-SP), and poly(ethylene glycol) diacrylate (PEGDA), the PEGDA chains first threaded into the cavity of α-CD/α-CD-SP and form inclusion complexes to generate the physical gel; then, the as-prepared physical gels were subjected to photopolymerization to form a covalently crosslinked network. With the contribution of both no-covalent and covalent bond, the dual-crosslinked hydrogels possess high tensile strength, which is about fifteen times that of the pure PEG hydrogel. And due to the sacrifice of no-covalent bond, hydrogels showed high energy dissipation ratio, up to 75.3% and high fatigue resistance during loading-unloading tests. While the ingenious introduction of SP moieties, enables the as-prepared gels photo-switchable spatiotemporal color changing behavior reversibly. Erasable patterns on hydrogels could be written using UV light and erased by Vis light for multiple cycles. This flexible hydrogel with good physical performance shows high potential in photochromic flexible wearable devices.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303556-ga1.jpg" width="321" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 116〈/p〉 〈p〉Author(s): Gazi A.K.M. Rafiqul Bari, Haekyoung Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electronic devices based on organic materials readily degrade owing to moisture or oxygen. Encapsulation materials and films made of inorganic and organic materials have been studied to arrest degradation, and polymeric materials have become more desirable owing to their flexibility, transparency, and processability. In this study, polymeric composite films that are fabricated under atmospheric conditions are studied. The composite encapsulation films consist of a combination of bisphenol A phenoxy resin and epoxy resin (POL) and synthesized benzoxazine monomer (eugenol-based Eu-Bzo (EZ), bisphenol-S based BPS-SA-Bzo (PZ), and bisphenol-AF based BPAF-SA-Bzo (FZ)). The composite with benzoxazine exhibits superior barrier characteristics with a highly hydrophobic nature compared to POL. The composite film with 3% Eu-Bzo exhibits lower moisture permeation rate of 2.02 g m〈sup〉−2〈/sup〉 d〈sup〉−1〈/sup〉 with 90% transparency in comparison to POL (3.65 g m〈sup〉−2〈/sup〉 d〈sup〉−1〈/sup〉) and PET (4.25 g m〈sup〉−2〈/sup〉 d〈sup〉−1〈/sup〉). The novel composition of epoxy and phenoxy resins along with benzoxazine is a potential candidate for fabricating barrier materials for flexible printed organic electronics.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719301995-ga1.jpg" width="265" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 19 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Kan Zhang, Mengchao Han, Lu Han, Hatsuo Ishida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of thermally stable resveratrol-based tri-functional benzoxazine resins have been synthesized using resveratrol, different amines (aniline, 4-chloroaniline and 3-aminophenylacetylene) and paraformaldehyde. The molecular structures of these benzoxazines have been characterized by 〈sup〉1〈/sup〉H and 〈sup〉13〈/sup〉C NMR spectroscopy and FT-IR spectroscopy. The assignments for the characteristic protons and carbons in oxazine rings are confirmed using two-dimensional (2D) NMR techniques, including 〈sup〉1〈/sup〉H-〈sup〉1〈/sup〉H NOESY and 〈sup〉1〈/sup〉H-〈sup〉13〈/sup〉C HMQC. Moreover, the ring-opening polymerization of benzoxazines is studied using 〈em〉in situ〈/em〉 FT-IR and differential scanning calorimetry (DSC), and the thermal stability and the flammability of the polybenzoxazines are also investigated by thermogravimetric analysis (TGA) and micro-scale combustion calorimetry (MCC), respectively. In addition to the advantages of lowest melting and polymerization temperatures amongst these resveratrol-based, tri-functional benzoxazines, the corresponding polybenzoxazine derived from benzoxazine containing acetylene shows highest thermal stability with a 〈em〉Tg〈/em〉 temperature higher than 350°C, initial degradation temperature at 10% weight loss at 465°C, and char yield of 74% at 800°C in nitrogen atmosphere. Furthermore, this polybenzoxazine also exhibits exceptionally low heat release capacity (30.7 Jg〈sup〉-1〈/sup〉K〈sup〉-1〈/sup〉) and total heat release value (6.0 kJ/g).〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719304926-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 18 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): S. García-Carvajal, D. Hernández-Martínez, I. Linzaga-Elizalde, P. Altuzar-Coello, J.L. Maldonado, M.E. Nicho〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, in-situ oxidative synthesis and properties of composites based in poly(3-hexylthiophene) (P3HT) with functionalized cadmium sulfide (CdS) nanoparticles (P3HT/CdS) are reported. CdS nanoparticles were synthesized by chemical precipitation and they were functionalized with diethyl[2-hydroxy-2-(thiophen-3-yl)ethyl] phosphonate. P3HT-CdS composites were synthesized by in-situ oxidative polymerization of 3-hexylthiophene (3HT) monomers in the presence of un-functionalized (as reference) and functionalized CdS nanoparticles (3HT/CdS weight ratio of 1:0.21). P3HT/CdS composites were characterized by 〈sup〉1〈/sup〉H NMR, FTIR, XRD, TGA, UV–Vis, and AFM analysis. Effect of functionalization of CdS on properties in P3HT/CdS composites was studied. A higher interaction between P3HT and CdS was obtained with functionalized CdS. Functionalization of CdS in P3HT-CdS composites led to increased optical absorbance, crystallinity, decomposition temperature and stability. In addition, their evaluation in photovoltaic devices is reported. Higher energy conversion efficiency of glass/ITO/PEDOT:PSS/P3HT-CdS: PC〈sub〉71〈/sub〉BM/PFN/FM devices was achieved when the CdS was functionalized.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571832531X-ga1.jpg" width="447" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Tongmou Geng, Guofeng Chen, Lanzhen Ma, Can Zhang, Weiyong Zhang, Heng Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Two new spirobifluorene-based conjugated microporous polymers, TS-TAD and TS-TADP, were constructed via Friedel-Crafts coupling reactions. TS-TAD and TS-TADP possess high BET surface area of 828 and 783 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉, large pore volume of 1.51 and 0.54 cm〈sup〉3〈/sup〉 g〈sup〉−1〈/sup〉, good stability, and display excellent guest uptake of 4.15 and 3.65 g g〈sup〉−1〈/sup〉 in iodine vapour as well as reversible adsorption of iodine in solution. The specific surface areas of CMPs were increased by the introduction of bispirofluorene rings compared with the corresponding parent polymers. TS-TAD has a similar structure to TS-TADP, but possesses larger specific surface area and pore values than TS-TADP, hence, TS-TAD has a higher adsorption capacity for iodine than TS-TADP. Moreover, the adsorption rate of TS-TAD is slower than that of TS-TADP in I〈sub〉2〈/sub〉 vapor, while it is faster than that of TS-TADP in cyclohexane solution. We also highlight that the both resulting CMPs exhibit outstanding performance for fluorescent sensing to iodine and nitroaromatic compounds, thus making the resulting CMPs ideal absorbent materials for reversible iodine capture, sensing iodine and nitroaromatic compounds to address environmental issues.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718324637-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 114〈/p〉 〈p〉Author(s): Guofei Sun, Jianheng Liu, Xing Wang, Ming Li, Xiang Cui, Licheng Zhang, Decheng Wu, Peifu Tang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Development of multi-responsive biodegradable micellar drug delivery systems for targeted cancer chemotherapy remains a major challenge. Here we demonstrate a kind of pH and reduction dual-responsive cationic polymer via an effective amine–epoxy polymerization, which could self-assemble into the biodegradable micelles in an aqueous solution. On account of the tumor cells or tissues possessing low pH values and high concentrations of reductive agents, these micelles exhibited the specific tumor target ability and maximal drug-release controllability inside tumor cells upon changes in physical and chemical environments, but presented excellent stability at physiological conditions. CCK-8 assay showed that these DOX-loaded micelles had a similar cytotoxicity for MCF-7 tumor cells as the free DOX molecules while blank micelles were low toxic to the cells. Confocal laser scanning microscopy (CLSM) observation revealed that the drug-loaded micelles were quickly internalized by endosomes to effectively restrain the cancer cell growth. These results indicated these biodegradable micelles could be the novel and efficient dual-responsive nanocarriers to improve the drug delivery and enhance the antitumor efficacy.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The biodegradable micelles, self-assembled by a reductive poly(β-hydroxyl amine), possess pH and redox dual-responsiveness for intracellular doxorubicin delivery.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930059X-ga1.jpg" width="437" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 26 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Xuejie Sun, Lin Ye, Xiaowen Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Microcellular polyetherimide (PEI)/carbon nanotube (CNT) composite foams were prepared via water vapor-induced phase separation (WVIPS) process. The hydroxylated multi-wall nanotubes (MWNTs-OH) were applied, and strong interfacial interaction formed with PEI molecules by high grafting ratio. Much PEI resin adhered to MWNTs-OH surface, resulting in an obvious increase of MWNTs-OH diameter and formation of coating structure. For the composite foams, the homogenous spherical-like cell structure can be observed. With increasing MWNTs-OH content, the tensile strength of the composite foam first increased, and then decreased, reaching maximum at 4wt% MWNTs-OH, a roughly 53% increase as a result of reinforcing effect of MWNTs-OH on matrix. Meanwhile, the storage modulus of the composite foam was much higher than that of pure PEI foam over the temperature range tested and still maintained above 610 MPa at 200°C, suggesting a remarkable improvement of thermal mechanical stability. MWNTs-OH distributed uniformly in the matrix, and under stress it was pulled out with surface completely wrapped by PEI resin, confirming that the failure mode was the deformation and destruction of non-interface resin. By incorporation of MWNTs-OH, the thermal decomposition temperature, char yield and LOI values of the composite foam increased, while the UL-94 tests were classed as a V-0 rating.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719304483-ga1.jpg" width="284" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Thi Phuong Thu Nguyen, Nadine Barroca-Aubry, Diana Dragoe, Sandra Mazerat, François Brisset, Jean-Marie Herry, Philippe Roger〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Grafting polymers bearing active esters, especially pentafluorophenyl methacrylate (PFPMA), onto or from surface is a promising approach towards the preparation of highly functional materials due to the ease in post-polymerisation modification of their corresponding polymers. Herein, a handy and efficient chemical modification process is proposed to modify extreme surface of poly(ethylene terephthalate) (PET) films towards the final purpose of grafting PFPMA polymer from PET surface via surface-initiated Cu(0)-mediated radical polymerisation. The characteristics of modified surface were evaluated after each step using various techniques including water contact angle, attenuated total reflectance Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron spectroscopy. Due to its robust conditions, the proposed approach allows grafting at ease PFPMA polymer from PET supporting surface, which not only enhances the reactivity of this inert material but also improves significantly the hydrophobicity of the surface.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930309X-ga1.jpg" width="247" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 25 April 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Satyaranjan Bairagi, S. Wazed Ali〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The requirement of portable and wearable electronic gadgets has been increased tremendously in the recent past due to the advancement of self-powered technologies. In the present work, a flexible nanogenerator based on fibrous nanocomposite has been successfully demonstrated. Nanogenerator is composed of PVDF as a polymer matrix and KNN nanorods as a filler material. The PVDF/KNN composite filaments have been prepared by twin-screw melt mixing and subsequently melt-spinning process with various percentage of KNN nanorods (0%, 2%, 4%, and 6% on the weight of polymer). The nanogenerator was made of PVDF/4%KNN NRs based filament which exhibited the highest 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mi〉F〈/mi〉〈mo stretchy="false"〉(〈/mo〉〈mi〉β〈/mi〉〈mo stretchy="false"〉)〈/mo〉〈/mrow〉〈/math〉 value (i.e. 26% polar 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mi〉β〈/mi〉〈/math〉 phase). The dielectric constant for the PVDF/4%KNN NRs filament based nanogenerator was 175, which is the highest value as compared to other nanogenerators (73 for P-PVDF, 134 for PVDF/2%KNN NRs and 131 for PVDF/6%KNN NRs filament based nanogenerators). The PVDF/4%KNN NRs filament based nanogenerator could also generate around 3.7V voltage and 0.326μA current, respectively. This performance of the nanogenerator is high enough to use in the portable and wearable electronic goods in textiles as a renewable power source.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719302010-ga1.jpg" width="348" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 14 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Jakob Stensgaard Diget, Lars Wagner Städe, Thorbjørn Terndrup Nielsen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A versatile atom transfer radical polymerization (ATRP) protocol was developed for the direct homo- and copolymerization of a sulfobetaine monomer, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium (SBMA), and a mono-functionalized β-cyclodextrin (βCD) methacrylate monomer. The polymers were characterized using 1- and 2D NMR spectroscopy and asymmetrical flow field-flow fractionation (AF4). Low dispersities (〈em〉Đ〈/em〉〈sub〉M〈/sub〉 = 〈em〉M〈/em〉〈sub〉w〈/sub〉/〈em〉M〈/em〉〈sub〉n〈/sub〉) and high initiator efficiencies, of both the homo- and copolymers, indicated good control over the polymerization. The work thus represent one of the few reports where low 〈em〉Đ〈/em〉〈sub〉M〈/sub〉 values are obtained for direct ATRP of SBMA and βCD monomers. The novel βCD copolymer showed salt-dependent upper critical solution temperature (UCST) behavior, while isothermal titration calorimetry revealed excellent binding properties.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718320275-ga1.jpg" width="452" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): Semra Unal, Sema Arslan, Tilbe Gokce, Beste Melek Atasoy, Betul Karademir, Faik Nuzhet Oktar, Oguzhan Gunduz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three-dimensional (3D) scaffolds that mimic in vivo tumor microenvironments can be used to study tumor response to anticancer treatments, since most preclinical combination treatment strategy for anti-glioma were evaluated with traditional 2D cell culture. In this research, the nanofiber scaffolds of polycaprolactone (PCL) containing gelatin (Gel) nano/microparticles coated with different concentrations of graphene oxide (GO) and were successfully produced by combining electrospinning and electrospraying techniques. Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectroscopy and mechanical testing were used to characterize the structure and properties of the composites. The results show that gelatin and graphene particles can be well dispersed in the polycaprolactone nanofiber matrix by using the combination technique of electrospinning and electrospraying. The presence of 1 wt% graphene oxide increased mechanical strength of PCL/Gel scaffold and was found to be well consistent with the drug treatments (temozolomide and bortezomib) and radiotherapy by not showing additional toxicity.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉3D PCL-Gel-GO composite scaffolds in the form of layer-by-layer structure were successfully fabricated by combining electrospinning and electrospraying techniques. The scaffolds were fabricated to mimic extracellular matrix of glioblastoma. Drug combination with radiation therapy were compared in 2D and the 3D scaffolds.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719300977-ga1.jpg" width="347" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 115〈/p〉 〈p〉Author(s): A. Wagner, A.M. Kreuzer, L. Göpperl, L. Schranzhofer, C. Paulik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Foamable inks for inkjet-based 3D printing processes, like PolyJet™ printing, open the way to produce light-weight additive manufactured parts in one process step. A new ink formulation, consisting of acrylic components and a modified blowing agent is presented. The goal is to directly produce foam during the printing process in contrast to other methods for 3D printing of foams, which are currently used. The presented characterization of the ink is focused on viscosity, decomposition temperatures of the blowing agents, and UV–polymerization of the ink matrix. More advanced ink characterization includes jetting tests at different inkjet-printheads and foaming of printed layers, as well as microscopic characterization of the foams.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719300990-ga1.jpg" width="246" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Ruidong Liu, Zhizhou Yang, Shiwei Chen, Jinshui Yao, Qiuhong Mu, Dan Peng, Hui Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel hyper-cross-linked porous polymer based on hexaphenyldisiloxane (HCP-DH) is synthesized through Friedel−Crafts reaction. The surface area of HCP-DH is up to 1084 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉, and it exhibits excellent adsorption capacities and reusability in organic dyes removal from water. Additionally, the structure of the synthesized polymer can be adjusted by alkali treatment, forming Si〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉OH groups in the pore structures. The porous polymer can be modified by the reaction of Si〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉OH groups and (3-aminopropyl)methyldiethoxysilane easily, and the amino functionalized porous polymer displays a good property in the field of chromium ion adsorption with an adsorption amount of 44.5 mg g〈sup〉−1〈/sup〉 under neutral condition. This method provides a new strategy for the synthesis and functionalization of porous polymers.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉〈em〉Functionalization of porous polymers:〈/em〉 Hexaphenyldisiloxane containing Si〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Si structures were used to prepare a novel hyper-cross-linked porous polymer via Friedel-Crafts alkylation. A large number of hydroxyl groups were formed in the structure of HCP-K obtained from HCP-DH by alkali treatment, which enables the facile functionalization of it by silane coupling agents.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310080-ga1.jpg" width="461" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 18 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Chuanli Ren, Xun Zhu, Na Zhao, Yong Shen, Longfei Chen, Shaofeng Liu, Zhibo Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We demonstrated that the dimeric 1-〈em〉tert〈/em〉-butyl-2,2,4,4,4-pentakis(dimethylamino)-2Λ〈sup〉5〈/sup〉, 4Λ〈sup〉5〈/sup〉-catenadi(phosphazene) supported on polystyrene (〈strong〉PS-〈em〉t〈/em〉-BuP〈sub〉2〈/sub〉〈/strong〉) was an efficient and recyclable catalyst for the ring-opening polymerization (ROP) of 〈em〉δ〈/em〉-valerolactone (〈em〉δ〈/em〉-VL). The heterogeneous catalyst 〈strong〉PS-〈em〉t〈/em〉-BuP〈sub〉2〈/sub〉〈/strong〉 could be recycled and reused for five consecutive cycles without significant decrease of catalytic activity. The monomer conversions maintained between 79% and 85% for five cycles. Using BnOH as initiator, the produced polyvalerolactones (PVLs) had controlled molecular weights (MWs) and narrow MW distributions (〈em〉Đ〈/em〉), and the products were free of catalyst by simple filtration. The 〈sup〉1〈/sup〉H NMR and MALDI-TOF characterizations of the obtained PVLs clearly indicated the presence of the initiator residue at the chain end.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉The eco-environmentally PVLs without catalyst-residue have been facilely synthesized using heterogeneous 〈strong〉PS-〈em〉t〈/em〉-BuP〈sub〉2〈/sub〉〈/strong〉 catalyst by simple filtration and without tedious purification process.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719309498-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 19 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Javier Pérez Quiñones, Cornelia Roschger, Andreas Zierer, Carlos Peniche, Oliver Brüggemann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Steroid-grafted silk fibroin (SF) conjugates with a degree of substitution of 1.1 to 4.3 mol% were efficiently synthesised for controlled release of anticancer drug diosgenin and agrochemicals DI31 and S7. The esterification of tyrosine residues in SF conjugates was confirmed using elemental analysis, ATR-FTIR and 〈sup〉1〈/sup〉H NMR spectroscopies. The thermal properties of SF conjugates analysed using DSC and TGA confirmed the ATR-FTIR findings on SF conjugates that β-sheet conformation was the predominant one in solid state. DLS revealed the impact of hydrophobic modification of SF on its hydrodynamic parameters, which resulted in more than doubled hydrodynamic sizes and zeta potential values. SF conjugates were observed as 250 to 600 nm aggregates formed by nanoparticles of 25-41 nm, as depicted using TEM and AFM. Controlled release of 40-50% grafted steroids from SF conjugates at pH 6.0 was achieved after 5 days. Agrochemical-grafted SF conjugates showed better plant growth enhancing effect than parent DI31 and S7 when evaluated on radish plants. SF conjugates showed low cytotoxicity at concentrations below 0.025 mg/mL when applied on MCF-7 and HEK-293 cells. Due to these results, we envisage that the synthesised DI31- and S7-grafted SF conjugates are good candidates for agrochemical use. This work also contributes to progress the use of silk fibroin in sustainable agriculture.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310468-ga1.jpg" width="318" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Hans R. Kricheldorf, Steffen M. Weidner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈span〉l〈/span〉-Lactide was polymerized in bulk with tin(II)2-ethylhexanoate (SnOct〈sub〉2〈/sub〉) as catalyst and salicylic acid as cocatalyst. The Lac/Cat ratio, Cocat/Cat ratio, temperature and time were varied. Increasing Cocat/Cat ratios reduced both, polymerization rate and molecular weight. However, under optimized conditions high molar mass (Mw up to 178,000), colorless, cyclic polylactides were formed in a short time. A few polymerizations performed at 160 and 180 °C with the combination of SnOct〈sub〉2〈/sub〉 and silylated salicylic acid gave similar results. Neat tin(II)salicylate was prepared from SnOct〈sub〉2〈/sub〉 and used for REPs of 〈span〉l〈/span〉-lactide in bulk, but the results were not better than those obtained from combinations of SnOct〈sub〉2〈/sub〉 and salicylic acid. Furthermore, dibutyltin salicylate was synthesized and used as catalyst for polymerizations of 〈span〉l〈/span〉-lactide in bulk at temperatures varying from 102 to 160 °C. Cyclic polylactides with Mw’s up to 40,000 were the main reaction products. At 100–102 °C a predominance of odd-numbered cycles was found proving a REP mechanism.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310018-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 11 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Yajun Ren, Xinxiang Cui, Lei Wang, Yanhe Wang, Libin Han, Qifeng Zhou, Xiaofeng Song〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thermo-responsive shape memory polymers which are a class of important smart materials can recover permanent shape from temporary shape by simple thermal stimulus, but most of the polymers lack of biodegradability and biocompatibility. Poly(L-lactide) (PLLA) is a green degradable thermoplastic, however, only limited studies involve controlling its shape change. In the work, a new 〈em〉x〈/em〉-shaped copolymer with defined architecture has been devised by using tetramethyltetravinylcyclotetrasiloxane (D〈sub〉4〈/sub〉〈sup〉vi〈/sup〉) as centronucleus and polytetrahydrofuran-〈em〉co〈/em〉-poly(〈em〉ε〈/em〉-caprolactone) (PTMG-〈em〉co〈/em〉-PCL) as branch to achieve PLLA shape memory. When the weight ratio of DAPP and PLLA is 50/50, the composite exhibits good thermo-responsive shape memory capacity because a balance between 〈em〉T〈sub〉m〈/sub〉〈/em〉 of the 〈em〉x〈/em〉-shaped polymer rand 〈em〉T〈sub〉g〈/sub〉〈/em〉 of PLLA is kept. The shape fixation ratio is 84% at 15 °C, and the recovery ratio 94% at 55 °C. And the shape memory capability does not change evidently after the reversible spiral transition is repeated for 30 times. At the same time, the composite shows great flexibility. So the obtained composite is promising for medical and bionic devices, self-healing systems, self-assembly structures.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A 〈em〉x〈/em〉-shaped polymer is designed by using tetramethyltetravinylcyclotetrasiloxane as centronucleus and polytetrahydrofuran-〈em〉co〈/em〉-poly(〈em〉ε〈/em〉-caprolactone) as branch to achieve PLLA shape memory.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719300205-ga1.jpg" width="292" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Yaoming Zhang, Leonid Ionov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper we report a new kind of self-rolling polyurethane (PU) film with the vertical gradient structure – top solid PU layer and bottom PU/SiO〈sub〉2〈/sub〉 hybrid layer. The differential swelling properties of these two layers allow the film to exhibit reversible shape transformation upon exposure to different solvents and their mixtures. We investigated correlation between shapes (tube/scroll/spiral) formed upon self-rolling and the size/shape of the films, fraction of silica particles, the aspect ratio of the film, and the external solvents. We have also found that Timoshenko bilayer model allows prediction of rolling behavior basing on properties of each layer. The reversible self-rolling behavior of the bilayer films with differential structure is expected to allow development of new actuator in the near future.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719312741-ga1.jpg" width="437" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 118〈/p〉 〈p〉Author(s): Maxime Vagenende, Geert-Jan Graulus, Jasper Delaey, Jasper Van Hoorick, Francis Berghmans, Hugo Thienpont, Sandra Van Vlierberghe, Peter Dubruel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Biodegradable polymers derived from renewable resources can be interesting materials for a plethora of applications and have therefore gained increased interest over the last decades. We herein report for the first time the synthesis of random copolymers based on lactic and mandelic acid via ring-opening-polymerisation of their corresponding O-carboxyanhydrides (OCA). Copolymers with tailored glass transition temperature and degradation time were obtained by adjusting the co-monomer feed during copolymerisation. Molecular weight analyses of the obtained copolymers indicated lower molecular weights in comparison to the target values. Our hypothesis that keto-enol tautomerisation of the OCA-monomers was the cause for this anomaly was substantiated by a mechanistic study of the OCA-polymerization reaction using lacOCA and manOCA as case study.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719302617-ga1.jpg" width="413" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Riccardo Narducci, Emanuela Sgreccia, Gianfranco Ercolani, Marco Sette, Simonetta Antonaroli, Luca Pasquini, Philippe Knauth, Maria Luisa Di Vona〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Amphoteric ionomers were synthesized with two different approaches to study the influence of a flexible side chain containing the functional groups vs grafting of the functional groups directly on the main chain. Poly(sulfone) was functionalized with 6-aminohexanoic acid (〈em〉ANF〈/em〉-1) or by successive carboxylation and amination of the aromatic main chain (〈em〉ANF〈/em〉-2). The samples were characterized by FTIR and NMR spectroscopies and thermogravimetric analysis. Acid and base constants were measured by titration. We also determined the hydration and the ionic conductivity for acid, base and zwitterionic forms made by variation of the pH.〈/p〉 〈p〉The basic forms containing dissociated carboxylic groups and mobile cations showed a higher water uptake and a higher conductivity. The zwitterionic forms presented a low water uptake for both polyelectrolytes and the lowest conductivity for 〈em〉ANF〈/em〉-2. The reduced conductivity in acidic conditions of 〈em〉ANF〈/em〉-1, where amine groups were protonated and only anions were mobile, was related to the position of ammonium moieties inside the side chain. This work showed how the properties of stimuli-responsive polymers depended on the position of the functional groups.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Properties of amphoteric ionomers are very dependent on the position of the ionic groups.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719309048-ga1.jpg" width="346" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 118〈/p〉 〈p〉Author(s): Elham Sadati Behbahani, Mehrorang Ghaedi, Arash Asfaram〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One-pot synthesis of magnetic lipid nanoparticles (MLNs) was accomplished andaccordingly, applied as a new sorbent for preconcentration and determination of curcumin from aqueous solution, followed by ultraviolet–visible (UV–Vis) spectrophotometry. The MLNs were prepared via microemulsion technique in the presence of oleic acid (OA) as the lipid and Tween 80 as the surfactant. The structure, morphology, and magnetic properties of the MLNs were characterized using FT-IR, XRD, FE-SEM, and VSM. The experimental results revealed that presented MLNs have superparamagnetic property, which results in the easy and quick phase separation and decrease in the extraction time. The influence of operational variables (pH, amount of sorbent, sonication time and type and volume of eluent) were assessed, investigated and finally optimized by the central composite design (CCD). Recoveries between 92.13% and 103.57% in real samples, RSD% 〈5%, and limits of detection and quantification of 0.022 and 0.073 mg L〈sup〉−1〈/sup〉, respectively are good indications of the best performance of the proposed understudy method.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310663-ga1.jpg" width="462" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Jeremy Winninger, Delia M. Iurea, Leonard I. Atanase, Slim Salhi, Christelle Delaite, Gerard Riess〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study reports the metal-free synthesis, the characterization and the micellization of a novel type of amphiphilic biocompatible and thermo-sensitive graft copolymers. It comprises a hydrolytically degradable hydrophobic poly(ε-caprolactone) (PCL) backbone and water-soluble thermo-sensitive poly(N-vinylcaprolactam) (PNVCL)-based side chains. The synthesis of these PCL-g-PNVCL graft copolymers, with controlled graft density, was carried out in a three-step process: (i) preparation of a chloro-functionalized PCL backbone by metal-free ring-opening copolymerization of ε-caprolactone and α-chloro-ε-caprolactone, (ii) generation of a macro-RAFT initiator by nucleophilic substitution of the chloro groups with potassium ethyl xanthogenate, and (iii) free radical controlled RAFT-Madix polymerization of NVCL. In order to tune the LCST of these graft copolymers with the human body temperature, a RAFT copolymerization of NVCL with N-vinylpyrrolidone (NVP) was performed in another series of reactions. Such PCL-g-PNVCL copolymers with a constant graft density of 15 grafting sites, DP〈sub〉n,backbone〈/sub〉 = 120 and DP〈sub〉n,average per graft〈/sub〉 = 54 lead in aqueous medium to stable micelles having an average hydrodynamic diameter Dv of 38 nm. The spherical morphology of these micelles was observed by TEM. Their thermo-sensitivity was further confirmed and a LCST value of 32 °C was determined. The incorporation of 10 or 20 mol% NVP units in the grafts of the PCL-g-P(NVCL-co-NVP) copolymers leads to a shift of LCST to higher temperatures in the range of 38– 40 °C.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310742-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Yu Zhang, Qiaoyan Zhu, Zhengdong Fei, Xianfu Lin, Bo Xia, Qi Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The synthesis of chiral polyesters with customized (〈em〉R〈/em〉)- or (〈em〉S〈/em〉)-configurations is of great significance but challenging. Despite many advances in enzymatic stereoselective polymerization, the limitations of inherent stereoselectivity and the narrow substrate scope of the biocatalysts used should be overcome. Herein, we combined chemical polymerization and highly selective enzymatic dynamic kinetic resolution (DKR) with tailor-made (〈em〉R〈/em〉)- or (〈em〉S〈/em〉)-selectivity enabled by engineered lipase to offer an efficient chemo-enzymatic route for the synthesis of enantiocomplementary (〈em〉R〈/em〉)- or (〈em〉S〈/em〉)-poly(〈em〉ω〈/em〉-substituted-〈em〉δ〈/em〉-valerolactone) (〈em〉ω〈/em〉-PVL). In the DKR of homoallylic alcohols, (〈em〉R〈/em〉)-selective wild-type 〈em〉Candida antarctic〈/em〉 lipase B (CALB) and an (〈em〉S〈/em〉)-selective CALB mutant (W104V/A281L/A282K) were used, providing enantiocomplementary homoallylic alcohol esters with 99% conversion and up to 99% enantiomeric excess (ee), which were further transformed into enantiopure lactone monomers. Using these monomers, ring-opening polymerizations catalyzed by a diphenyl phosphate system successfully provided (〈em〉R〈/em〉)- or (〈em〉S〈/em〉)-〈em〉ω〈/em〉-PVL with aromatic and aliphatic side chains. Additionally, their structure and thermal properties were characterized by nuclear magnetic resonance (NMR), circular dichroism (CD) spectra, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). (〈em〉R〈/em〉)- or (〈em〉S〈/em〉)-〈em〉ω〈/em〉-PVL exhibited vertically mirrored negative and positive CD signals, and were thermally stable while having different decomposition temperatures (T〈sub〉d〈/sub〉), which are highly dependent on their molecular weight and side chain structure. It was concluded that stereoregularity has significant influence on the crystallization of the polyesters.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719309097-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Ghazaleh Salehi, Aliasghar Behnamghader, Saeed Hesaraki, Masoud Mozafari〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉During the past few years, invasive surgery operations using injectable systems, have been applied for the treatment of osteoporosis bone defects. In this research, different injectable pastes made from natural polymer such as gelatin (Ge), carboxymethyl cellulose (CMC), alginate (Alg) and inorganic materials containing hydroxyapatite (HA) and biphasic calcium phosphate (BCP) were studied. BCP was fabricated via solid state reaction. Evaluation of BCP crystalline structure confirmed the presence of tricalcium phosphate (TCP) and HA phases. The morphology of calcium phosphate powders and the paste showed fine particles and homogeneous distribution, respectively. Consistency, injectability, washout and the rheology behavior of pastes were evaluated too. According to the results, the pastes consisted of considerable values of calcium phosphate content (about 65%) and injectability of 84% and 91% with acceptable degradation in PBS, were found for Gel/0.4% CMC and Gel/1.2% Alg pastes, respectively. It could be concluded that the addition of carbohydrate polymers (CMC and Alg) to the formulation of samples could be an effective way to adjust the final performance of the hybrid injectable bone pastes.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930686X-ga1.jpg" width="321" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Wenhao Qian, Haiyan Zhang, Tao Song, Mao Ye, Chun Feng, Guolin Lu, Xiaoyu Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new methacrylate monomer containing ferrocene unit and disulfide bond, 2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocenecarboxylate (FcMAss), was prepared by subsequent esterification reaction with bis(2-hydroxyethyl) disulfide and methacryloyl chloride using ferrocenecarboxylic acid as starting material. A series of well-defined poly(2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocenecarboxylate) (PFcMAss) homopolymers with narrow molecular weight distributions (〈em〉M〈/em〉〈sub〉w〈/sub〉/〈em〉M〈/em〉〈sub〉n〈/sub〉 〈 1.30) was then obtained by atom transfer radical polymerization (ATRP) of FcMAss monomer in toluene. Block copolymerization of FcMAss monomer was initiated by PEG-Br macroinitiator in THF to afford a poly(ethylene glycol)-〈em〉b〈/em〉-poly(2-((2-(methacryloyloxy)ethyl)disulfanyl)ethyl ferrocenecarboxylate) (PEG-〈em〉b〈/em〉-PFcMAss) diblock copolymer with a relatively low dispersity (〈em〉M〈/em〉〈sub〉w〈/sub〉/〈em〉M〈/em〉〈sub〉n〈/sub〉 = 1.34). Graphene oxide (GO)-based nanocomposite, GO-PFcMAss, was prepared by surface-initiated ATRP of FcMAss via the grafting-from strategy, using GO-based macroinitiator obtained by treating tris(hydroxymethyl) aminomethane (TRIS)-modified GO with 2-bromo-2-methylpropionyl bromide. The nanocomposite was characterized by FT-IR and XPS, and showed excellent dispersibility and colloidal stability.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉This article reports a new ferrocene/disulfide-containing methacrylate monomer and its nanocomposite via surface-initiated ATRP.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310924-ga1.jpg" width="416" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 1 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): George Vamvounis, Marina Fuhrer, Kevin Keller, Lukas Willig, Ami Koizumi, Hsuan-Ming Hu, Mei Gao, Toby D.M. Bell〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The preparation, photophysical characterization and sensing of a series of highly luminescent poly(fluorene-〈em〉alt〈/em〉-phenylene)s (PFP) were studied. These PFP polymers varied the phenylene linkage in the 1,4 (PFP-p), 1,3 (PFP-m) and 1,2 (PFP-o) positions. The photoluminescence of these polymers ranged from ultraviolet to blue in color in both solution and film states by simply varying the linkage of the phenylene moiety. Photon Electron Spectroscopy in Air (PESA) revealed that the change in the emission was primarily attributed to the difference of the electron affinity of the polymer. Stern-Volmer quenching studies indicated that these poly(fluorene-〈em〉alt〈/em〉-phenylene) polymers are highly sensitive towards nitroaromatic materials in solution, particularly in comparison to the reference poly(9,9-di-〈em〉n〈/em〉-hexylflourene) (PDHF). These PFP polymers were found to be four to ten times more sensitive towards dinitrobenzene as compared to PDHF. In addition, PFP-o displayed the highest polymer-based Stern-Volmer quenching towards the taggant DMNB. The solid-state fluorescence quenching of the PFP-p and PFP-m films using DMNB was enhanced (up to 71.5%) compared to the reference PDHF (59.6%) and was attributed to both thermodynamic and diffusion kinetic factors.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310717-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Rosa M. Morales-Román, Maria Guillot-Ferriols, Laura Roig-Pérez, Senentxu Lanceros-Mendez, Gloria Gallego-Ferrer, José Luis Gómez Ribelles〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Poly(vinylidene fluoride) (PVDF) is a semicrystalline polymer with four crystalline phases, of which the all trans conformation (β-phase) is the one with the largest piezoelectric response and best electroactive properties. This smart material is able to reproduce physiological events such as inherent bone piezoelectricity, making it a perfect candidate to drive the osteogenic differentiation of mesenchymal stem cells (MSCs) towards the osteogenic lineage. The influence of topography on the adhesion, proliferation and maintenance of multipotency of this type of cell is well established and has confirmed that the production of variable porosity substrates is a suitable approach for cell therapy. In this work, novel PVDF microporous membranes in the β-phase were developed by the freeze-extraction technique. Several concentrations of PVDF in N,N-dimethylformamide (10, 15 and 20% w/v) were used to obtain membranes with different grades of porosity in the range of 80 to 84 %. The cell culture supports thus produced were found to possess good crystallinity (66%), β-phase presence (94%) and a microstructure based on spherulite agglomerations with a diameter of spherulite in the order of 1 μm that is higher as the polymer concentration increases. The membranes have good mechanical properties and the storage modulus, with values between 5 and 47 MPa, rises with the polymer content of the starting solution. Porcine bone marrow mesenchymal stem cells (pBM-MSCs) were used to study cell adhesion and proliferation. Regarding cell adhesion at 24h, the cells preferred the more porous structures and had round focal adhesions with well-developed cytoskeletons, while they had a round morphology on the less porous membranes. The cells preferred the less porous membranes to proliferate, even though the initial morphology at 24h showed poor adhesion. These findings confirm that the controlled microporosity of β-phase PVDF membranes can be produced by freeze extraction and offer the possibility of modifying the adhesion and proliferation of pBM-MSCs on these substrates.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719306913-ga1.jpg" width="287" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Olatz Guaresti, Senda Basasoro, Kizkitza González, Arantxa Eceiza, Nagore Gabilondo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thiol modified chitosan (CsSH) was covalently cross–linked with a water–soluble bismaleimide (BMI) to obtain chitosan–based hydrogels by thiol–Michael addition reaction at physiological conditions. By modifying the composition of the as–prepared hydrogels, final properties could be modulated. Thus, the rheological and swelling behaviour were controlled by altering the amount of cross–linking agent in the networks. An increase in the cross–linker ratio leaded to an increase in the hydrogel storage modulus and decrease in swelling ratio due to provided rigidity to the structure and a higher cross–linked degree. Furthermore, 3D porous structures were observed to be sensitive to pH stimulus and showed interesting degradation kinetics under specific enzymes, suggesting the formation of these novel materials to be worthy of biomedical applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719309565-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Neda Radovanović, Ivana Malagurski, Steva Lević, Milan Gordić, Jelena Petrović, Vladimir Pavlović, Miodrag Mitrić, Aleksandra Nešić, Suzana Dimitrijević-Branković〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉New agar-based composite films with increasing Cu-carbonate and Cu-phosphate mineral phase content were prepared by in situ mineralization and solvent casting method. SEM and optical analysis revealed that Cu-carbonate phase had better compatibility with agar matrix than Cu-phosphate phase. Incorporation of both mineral phases improved mechanical and water vapor barrier properties of the obtained mineralized films, in concentration dependent manner. When 5 mM of carbonate precursor was incorporated into agar matrix, mechanical resistance was enchanced for 44% and water vapor barrier property for 40%. The release of Cu (II) was higher in acidic conditions for both mineralized composites and remained in the range of specific release limits for this metal. In addition, both mineralized composite films exhibited distinctive antimicrobial activity against Gram-negative (〈em〉Escherichia coli〈/em〉) and Gram-positive (〈em〉Staphylococcus aureus〈/em〉) bacteria. Overall, the Cu-carbonate and Cu-phosphate mineralized agar films showed potential to be used for food packaging materials, agriculture or medical purposes.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719309589-ga1.jpg" width="353" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Yu Dai, Chenbo Meng, Siyi Tang, Jiaqiang Qin, Xiangyang Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Weak transverse interaction of aramid fiber leads to low compressive strength, which is a prominent problem for its further application. In this study, a novel strategy by constructing dendritic structure in aramid fiber was conducted to solve the problem. Hyperbranched aromatic polyamide and linear aromatic polyamide are grafted on nano-SiO〈sub〉2〈/sub〉 respectively, which will present absolutely different conformations. Structure of the SiO〈sub〉2〈/sub〉 derivates was analyzed in detail by Fourier transform infrared spectroscopy (FTIR), dynamic laser scattering (DLS) and X-ray photoelectron spectroscopy (XPS). Compared with linear polyamide, hyperbranched polyamide tends to grow in multiple directions during polymerization due to significant steric effect, which can be confirmed by molecular simulation. When the SiO〈sub〉2〈/sub〉 derivates were blended in aramid fiber, three-dimensional dendritic structure will be constructed by utilizing distinctive conformation of the hyperbranched polyamide. When loading content of nano-SiO〈sub〉2〈/sub〉 derivate modified by hyperbranched polyamide in aramid fiber is 0.5 wt%, compressive strength of the fiber is improved by nearly 114%. Moreover, tensile strength and modulus are improved by nearly 13% and 9% respectively. Therefore, comprehensive performance of the aramid fiber can be remarkably improved by utilizing unique conformation of the hyperbranched polyamide, even if loading content of the SiO〈sub〉2〈/sub〉 derivate is relatively low.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719314880-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Yelda Ertas Dogan, Bekir Satilmis, Tamer Uyar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, a blend solution of hydroxypropyl-β-cyclodextrin (HPβCD) and benzoxazine monomer (BA-a) was prepared in dimethylformamide to obtain HPβCD/BA-a microfibers by electrospinning technique. The electrospun HPβCD/BA-a microfibers were then thermally cured to obtain crosslinked PolyHPβCD/PolyBA-a microfibers. The compositions of HPβCD (120%, 〈em〉w/v〈/em〉) and BA-a (25%, 〈em〉w/v〈/em〉) were determined as an optimum concentration for producing bead-free and uniform microfibers from blend of HPβCD and BA-a (HPβCD/BA-a). Afterwards, the HPβCD/BA-a microfibers were thermally cured using step-wise curing method to obtain water-insoluble crosslinked PolyHPβCD/PolyBA-a fibrous membrane (FM). However, the fibrous structure of PolyHPβCD/PolyBA-a membrane was subjected to some morphological deformation during thermal curing. Therefore, citric acid (CTR, 5% and 15%, 〈em〉w/v〈/em〉) was incorporated into blend of HPβCD15/BA-a and it was named as HPβCDx/BA-a where x represents the amount of CTR (〈em〉w/v〈/em〉) in the system. Blend solution of HPβCD15/BA-a was electrospun into microfibers to facilitate the crosslinking and to improve thermal resistance of the crosslinked fibrous membrane (PolyHPβCD15/PolyBA-a). Structural changes and thermal properties of the microfibers before and after curing were studied. Scanning electron microscopy was further used to monitor the morphology and stability of crosslinked PolyHPβCD/PolyBA-a microfibers in water and organic solvents. Consequently, PolyHPβCD15/PolyBA-a microfibers showed an enhanced structural stability in water and organic solvents along with thermal resistance, indicating successful crosslinking. Afterwards, the molecular separation ability of self-standing PolyHPβCD15/PolyBA-a FM was evaluated using dye mixture of Methylene Blue (MB) and Methyl Orange (MO). While both dye molecules are able to form a host-guest interaction between cyclodextrin molecules, crosslinked PolyHPβCD15/PolyBA-a FM showed sorption selectivity against cationic MB dye due to favorable electrostatic attractions between MB and HPβCD compared to anionic MO dye and HPβCD. In addition to selective sorption behavior of MB dye over MO dye, crosslinked PolyHPβCD15/PolyBA-a FM exhibited a decent adsorption capacity for MB in water.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719311577-ga1.jpg" width="462" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Ben A. Drain, C. Remzi Becer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉2-oxazoline based polymers are attracting more and more attention in the last decade owing to their unique properties not only in biomedical applications but also in lubrication. Their combination with widely used polymers that are usually synthesized via controlled/“living” polymerisation techniques allows the design of novel polymer architectures and further increases the range of properties accessible from poly(2-oxazoline) based materials. However, there are several synthetic challenges to achieve a successful combination of these polymers and various techniques, such as click reactions, macromonomers, and heterobifunctional initiators have been reported in the literature to overcome these challenges. In this review, various synthetic methods to combine poly(2-oxazoline)s with vinyl based polymers have been discussed including the pros and cons of each method.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719312595-ga1.jpg" width="273" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 17 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Kairui Zhang, Fei Cheng, Kang Zhang, Jianbo Hu, Changxue Xu, Yi Lin, Mi Zhou, Puxin Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Long-chain fatty acid starch esters are prepared by esterification of stearic acid or lauric acid with corn starch in urea/NaOH aqueous solutions. Effect of esterify condition on the degree of substitution (DS) and the structure and performance of the products are studied. The synthesized starch stearate and starch laurate are obtained a DS of 0.065 and 0.074, respectively, higher than the reported values by the water medium method. Esterification of starch is proved by Fourier transformed infrared and 〈sup〉1〈/sup〉H nuclear magnetic resonance. The structure and thermal properties of starch esters are confirmed by X-ray diffraction, Scanning Electron Microscope, Thermogravimetry and Differential Scanning Calorimetry. The results show that the starch esters, with lower crystallinity than starch, has better thermostability, emulsibility, transparency, freeze-thaw stability and moisture absorption than native starch, but higher glass transition temperature (〈em〉T〈/em〉〈sub〉g〈/sub〉) within the limited DS.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719311127-ga1.jpg" width="317" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 16 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Samira Sanjabi, Zeinab Alinejad, Alireza Mouraki, Ali Reza Mahdavian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Stimuli-responsive materials based on spirooxazines are new class of smart materials that have received great deal of attentions in the recent decades. Spirooxazine derivatives, as photochromic compounds, represent many advantages like high photofatigue resistance. But, they usually suffer from very short life time of the colored form and quick reversion to its colorless isomer which limits their application at ambient conditions. Here, spironaphthoxazine (SNO) and spironaphthoxazine acrylate (SNO-Ac, as the monomer) were synthesized and characterized by FTIR and 〈sup〉1〈/sup〉H NMR spectroscopy. Then, temperature-dependent photochromic behavior of SNO solution in different solvents was studied by UV–Vis spectroscopy at room and low temperatures. The absorption band relating to the obtained meronaphthoxazine (MNO) in 500–600 nm was not clearly observed after UV irradiation (365 nm) at room temperature, while an intensive absorption was appeared at −30 and −20 °C. SNO-Ac was then copolymerized with methyl methacrylate through solution and miniemulsion polymerizations. The obtained nanoparticles (ranging from 64 to 94 nm in size) represented reduced thermal reversion in comparison with the solution-based copolymers, but still not enough for room-temperature observations. Thereafter, an evident coloration was gained at normal conditions by introducing butyl acrylate to the above-mentioned copolymeric latex. The obtained flexible copolymer chains were found to facilitate SNO to MNO isomerization and the kinetic of photoisomerization in such systems were studied comprehensively. This resulted in photothermal stability enhancement of MNO at ambient conditions by their embedding in the prepared acrylic terpolymer nanoparticle to decrease its decoloration rate as a novel approach in such systems.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719310146-ga1.jpg" width="397" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 15 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Yitong Zhang, Xiaoyun Liu, Guozhu Zhan, Qixin Zhuang, Ruhong Zhang, Jun Qian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper a novel bio-based benzoxazine, dehydroabietylamine benzoxazine monomer (D-Bz), was synthesized and a series of copolymers were prepared by using D-Bz and two other bio-based benzoxazines 6-allyl-8-methoxy-3-octadecyl-3, 4-dihydro-2H-benzoxazine (S-Bz) and 6-allyl-3 –(furan-2-ylmethl)-8-methoxy-3, 4-dihydro-2H-benzoxazine (F-Bz). The structure, morphology and curing process are characterized by 〈sup〉1〈/sup〉H nuclear magnetic resonance spectroscopy (〈sup〉1〈/sup〉H NMR), mass spectrometry (MS), fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Electrochemical techniques such as open circuit voltage time (OCPT), Tafel and electrochemical impedance spectra (EIS) were used to study their electrochemical corrosion properties. Results show that among these copolymer, when the ratio of S-Bz: D-Bz: F-Bz is 1:6:3, the copolymer has good synergistic effects, showing a lower dielectric constant (2.47 at 1000 Hz), higher crosslink density (5.29*E〈sup〉−4〈/sup〉 mol/ml), lower corrosion current (0.030 µA/cm〈sup〉2〈/sup〉) and the best electrochemical corrosion efficiency (99.73%).〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719304495-ga1.jpg" width="234" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Elzbieta Pedziwiatr-Werbicka, Katarzyna Milowska, Volha Dzmitruk, Maksim Ionov, Dzmitry Shcharbin, Maria Bryszewska〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The use of nanotechnology in biology and medicine has been marked by rapid progress of these industries due to the emergence of new devices, supramolecular systems, structures, complexes and composites. One striking example of nanotech polymers is dendrimers. Their structure is formed by branches of monomeric subunits diverging in all directions from the central core. In choosing monomers and functional groups in synthesis, one can precisely set the properties of the resulting macromolecules. Currently, with modifications, 〉100 types of dendrimers have been synthesized. Of these, the 5 most common families can be distinguished: (i) Polyamidoamine (PAMAM) dendrimers are based on the ethylenediamine core and their branches are constructed from methyl acrylate and ethylene diamine. Currently, there is a large selection of PAMAM dendrimers with surface groups of many types. (ii) Polypropyleneimine (PPI) dendrimers are based on a butylenediamine core and polypropyleneimine monomers. In addition to PPI, the second popular abbreviation of these dendrimers is DAB (diaminobutyl) – from the name of the nucleus. Currently commercially available are (iii) Phosphorus dendrimers. In phosphorus dendrimers, phosphorus atoms are present in the core and branches of the dendrimer. (iv) Carbosilane dendrimers are based on a silicon core and have ammonium or amino groups on the periphery. (v) Poly(lysine) and poly(L-ornithine) dendrimers are a dendrimeric structure composed of amino acids residues. Characteristic surface groups possessing hydrophobic or hydrophilic components help to encapsulate the ligands inside or attach them to the surface, ensuring protection from degradation. Drug molecules complexed with dendrimer can be delivered to target cell where they are released from the complex. Dendrimers can improve the bioavailability of drugs by increasing their solubility in water, and changing surface charge, thereby reducing toxicity. In this review, the properties of dendrimers as drug carriers are discussed.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719308602-ga1.jpg" width="295" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Edward A. Apebende, Laurent Dubois, Nico Bruns〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Block copolymers with a functional group between their blocks are relatively little explored even though this molecular architecture can reduce the aggregation of the functional groups, promote the phase separation in nanophase-separated materials, and has other interesting effects. Spiropyrans are well-known for their ability to switch to their polar merocyanine form in response to light, force and other stimuli. The synthesis of stimuli-responsive AB-type block copolymers with spiropyran moieties located at the junction of the blocks is presented here. A homopolymer is synthesized from a trimethylindolenine-based atom transfer radical polymerization (ATRP) initiator, followed by its modification to a spiropyran end-functionalized polymer. The spiropyran functionalized polymer is then used as a macro-initiator for the synthesis of a second polymer block by ring opening polymerization (ROP). Alternatively, spiropyran homopolymers are conjugated to other preformed polymers by esterification. The resulting block copolymers reversibly switch under UV and white light irradiation over multiple cycles, and a block copolymer reduced the tendency of the merocyanine to aggregate during switching. The stimuli-responsive block copolymer could be useful for a range of applications, e.g. for bioinspired polymersome nanoreactors, or in membranes with switchable permeability.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S001430571930432X-ga1.jpg" width="247" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 4 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Kyle Kingsley, Oleh Shevchuk, Vasylyna Kirianchuk, Ananiy Kohut, Stanislav Voronov, Andriy Voronov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Highly hydrophobic vinyl monomers from soybean (SBM) and olive (OVM) oil with different amounts of unsaturation were copolymerized in emulsion with significantly more soluble in water comonomers, methyl methacrylate (MMA), vinyl acetate (VA), and methyl acrylate (MA). Our intention was to demonstrate that higher aqueous solubility of the comonomer impacts the mechanism of the emulsion process by balancing latex particle homogeneous and heterogeneous (micellar) nucleation.〈/p〉 〈p〉Using an experimental method based on water insoluble dye Blue 70, it is shown that particle nucleation indeed depends to a great extent on aqueous solubility of the comonomer, along with the plant oil-based monomer (POBM) content in the feed. Upon addition of POBM into the monomer mixture with MMA (aq.solubility 1.5 wt%), the latex polymer particles originating from micellar nucleation essentially increased. In copolymerization of POBM with MA (aqueous solubility 4.9 wt%), this effect is even more pronounced. Those findings clearly indicate that copolymerization loci change when monomer feed hydrophobicity increases, and the magnitude of this effect is dependent on the comonomer aqueous solubility.〈/p〉 〈p〉Experimentally determined changes in reaction order with respect to emulsifier and initiator upon addition of POBM confirm that kinetics of emulsion copolymerization is impacted by comonomer aqueous solubility. The latter finding can be indicative of changing latex particle nucleation mode when monomer feed hydrophobicity changes.〈/p〉 〈p〉Overall, the portion of latex particles originating through micellar nucleation is higher in the copolymerization of more unsaturated SBM (with both MMA and MA) in comparison to OVM. No impact of POBM content on the reaction kinetics was observed in copolymerization with VA (aq. solubility 2.5 wt%). Here, high reactivity of growing PVA radicals in chain transfer reactions makes the presence of POBM in monomer feed kinetically irrelevant.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719307554-ga1.jpg" width="379" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 10 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Qian Zhang, Ning Liu, Ming-hui Xu, Ling Ma, Xian-ming Lu, Yuan-jie Shu, Xiao-chuan Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel energetic polymer binder was developed through ring opening copolymerization of 3-nitratomethyl-3-methyloxetane (NIMMO) with (HTPE) as a macroinitiator to form tri-block copolymer polyNIMMO-HTPE-polyNIMMO. The structure of tri-block copolymer was confirmed by FTIR, 〈sup〉1〈/sup〉H NMR, 〈sup〉13〈/sup〉C NMR and GPC. In comparison with HTPE, polyNIMMO-HTPE-polyNIMMO has a higher viscosity because of its increased molecular weight with additional –ONO〈sub〉2〈/sub〉 as side groups and strengthen intermolecular interaction. The glass transition temperature studies show two glass transition processes in their DSC curves. One signal around -69 °C arises from the HTPE segment, while the other signal around -30 °C is related to the terminal polyNIMMO segments in the tri-block polymers. The TGA-DTG and DSC curves indicate that polyNIMMO-HTPE-polyNIMMO has a good thermal stability and its exothermic decomposition peak was found to be around 220 °C. The kinetic parameters and the thermodynamic parameters for the thermal decomposition of polyNIMMO-HTPE-polyNIMMO-IV were obtained from the DSC data by non-isothermal methods proposed by ASTM E696 and FWO. These results demonstrate that tri-block copolymer polyNIMMO-HTPE-polyNIMO might be a potential energetic propellant binder.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719306469-ga1.jpg" width="258" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 3 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Rutusmita Mishra, Ritu Varshney, Neeladrisingha Das, Debabrata Sircar, Partha Roy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An ideal scaffold which mimics extracellular matrix as an artificial bone graft substitute is the need of current clinical management of orthopaedic complications. In this study, a porous biomimetic scaffold was synthesized using in situ gas foaming method. Briefly, a blend of gelatin and polyvinylpyrrolidone (PVP) was crosslinked with glutaraldehyde and lyophilized. The blending of two polymers were confirmed with FTIR, XRD and TGA analysis. The synthesized scaffold was further characterized for its biocompatibility and osteogenic potential. The physico-chemical properties like microarchitecture, porosity, water adsorption ability, and mechanical strength were also investigated. Further, the enhanced proliferation and migration of murine mesenchymal stem cells (C3H10t1/2 cells) through interconnected pores of the scaffold over an extended time period suggests the cytocompatibility of scaffold. Next, the biocompatibility of the scaffold was confirmed by 〈em〉in ovo〈/em〉 implantation on the chorioallantoic membrane (CAM) using chicken embryo. In addition, increased matrix mineralization was confirmed by alizarin red staining and EDX analysis of apatite depositions over the scaffold, when induced with osteogenic media. In summary, these findings demonstrate biocompatibility and osteo-inductive potentials of the gelatin-PVP biomimetic polymer composite scaffold with suitability as bone graft substitute material.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718320032-ga1.jpg" width="284" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Anahita Rohani Shirvan, Azadeh Bashari, Nahid Hemmatinejad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Buccal mucosa is considered as a convenient and easily accessible site for the drug administration for both local and systemic delivery. Mucoadhesion is a process involving chemical interactions between mucin and polymers. The use of mucoadhesive polymers in buccal drug delivery has gained a great attention. Various mucoadhesive dosage forms, including tablets, patches, disks, wafers, ointments and gels have recently been developed. Amongst them, buccal patches offer greater flexibility and comfort than the other forms. Smart materials such as stimuli-responsive hydrogels, liposome-based patches, polymeric micelles, etc. play a vital role in the development of these drug delivery systems by their efficient carrier capacity, prolonging the residence time of the drug at the site of absorption, improved drug bioavailability, reduced dosing frequency and improved patience compliance. There are different designs and manufacturing methods such as electrospinning, electrospraying and 3D printing techniques which considered as novel and efficient methods for preparation of buccal patches with some unique characteristics than traditional approaches such as solvent casting. In this review an attempt has been made to discuss and introduce the most promising smart polymeric materials, new designs and manufacturing methods for the development of buccal mucoadhesive patches as a new controlled drug delivery system.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719311851-ga1.jpg" width="161" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 11 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Anand J. Gaston, Gabija Navickaite, Gary S. Nichol, Michael P. Shaver, Jennifer A. Garden〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The ring-opening polymerisation of lactide is a useful means to prepare biodegradable materials with well controlled polymer architectures and bespoke material properties. While homogeneous ligand-Al-OR complexes have shown great success in this field, initiation from ligand-AlCl complexes has lagged behind. Here, we report four new salen-AlCl complexes featuring NEt〈sub〉2〈/sub〉-substituents, which display high catalyst activities towards 〈em〉rac〈/em〉-lactide ring-opening polymerisation (〈em〉k〈/em〉〈sub〉obs〈/sub〉 〈 1.9 × 10〈sup〉−3〈/sup〉 s〈sup〉−1〈/sup〉) 〈em〉via in situ〈/em〉 activation with a single equivalent of propylene oxide. Incorporating Lewis basic NEt〈sub〉2〈/sub〉 groups into the ligand scaffold not only improves the initiation efficiency but also avoids the need for a Lewis basic co-catalyst and excess epoxide. Notably, studies of our amino-substituted catalysts reveal that the formation of a hexacoordinate aluminate species may hinder rather than enhance catalytic activity.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719311000-ga1.jpg" width="337" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal, Volume 119〈/p〉 〈p〉Author(s): Marin Simeonov, Angela Gussiyska, Jasmina Mironova, Denitsa Nikolova, Anton Apostolov, Kostadinka Sezanova, Elena Dyulgerova, Elena Vassileva〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Dental caries remains one of the most prevalent bacteria caused diseases affecting both adults and children. It is a dynamic process which progress depends on the interplay between demineralization, caused by the bacteria produced acids from the consumption of sugars, and remineralization that takes place due to the saliva protective qualities/functions. The acids start to dissolve calcium and phosphate from the enamel (demineralization) and at the initial stage, when the tooth damage is not significant, the opposite process – the calcium and phosphate deposition (remineralization) could arrest the caries development thus making the caries a preventable disease. The development of new materials for enhancing the remineralization process is one of the main approaches of the non-invasive dentistry and also one of the main challenges of the advanced dental materials science.〈/p〉 〈p〉In the present study, hybrid chitosan/calcium phosphates microgels were developed for the first time. Their potential and effectiveness as remineralizing agent, enhancing the nucleation and growth of calcium phosphates on a model demineralized enamel surface, was revealed. The hybrid microgels formation was guided by the chitosan macromolecules which acted as a template for the calcium phosphate deposition and resulted into 〈em〉in situ〈/em〉 formation of amorphous to poorly crystalline non stoichiometric hydroxyapatite. These newly developed hybrid materials have several advantages as remineralizing agent, including bio-adhesiveness, antimicrobial properties as well as continuous supply of calcium and phosphate ions to ensure the successful remineralization of the model initial caries lesions.〈/p〉 〈p〉Thus, the study reveals a simple and easy to apply remineralization procedure based on the newly developed hybrid materials that could be effectively used for arresting and enhancement of the remineralization of early-stage caries development taking advantage of the night regime of the oral cavity habits. This simple approach has been tested and proved to be effective for remineralization of initial enamel demineralization.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305719303027-ga1.jpg" width="349" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉