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  • Artikel  (348.874)
  • Artikel: DFG Deutsche Nationallizenzen  (348.874)
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  • 1
    Digitale Medien
    Digitale Medien
    Meetings of interest (2001)
    Springer
    JBIC 6 (2001), S. 659-660 
    Details
    ISSN: 1432-1327
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00010669
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  • 2
    Digitale Medien
    Digitale Medien
    SBIC News (2001)
    Springer
    JBIC 6 (2001), S. 661-662 
    Details
    ISSN: 1432-1327
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00010670
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  • 3
    Digitale Medien
    Digitale Medien
    Electroinitiated polymerization of 2-allylphenol (2000)
    Springer
    Polymer bulletin 45 (2000), S. 45-52 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Redox behaviour of 2-allylphenol (2APhOH) was studied by using cyclic voltammetry (CV) and electroinitiated polymerization was conducted at the measured peak potentials. Constant potential electrolysis (CPE) of the monomer was carried out in acetonitrile-sodium perchlorate, solvent-electrolyte couple, at room temperature. Polymerization of the monomer yielded insoluble polymer films on the surface of the electrode together with the low molecular weight polymers in the bulk of the solution. The structural analysis of the polymers were carried by 1H-NMR and FTIR spectroscopy. Molecular weight of the soluble polymer was determined by GPC. Thermal properties of the polymer film and soluble polymer were studied by DSC. The course of electroinitiated polymerization was monitored by in-situ UV-VIS spectroscopy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070055
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  • 4
    Digitale Medien
    Digitale Medien
    Synthesis and NMR characterization of a novel polyaniline derivative (2000)
    Springer
    Polymer bulletin 45 (2000), S. 61-68 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The synthesis and solution-state NMR investigation of the structure of a novel type of water-soluble polyaniline (PANI) derivative in leucoemeraldine and emeraldine oxidation states is presented. Copolymers of 3-aminobenzenesulfonic acid and 2-methoxyaniline (PMAOMA) with various monomer molar ratios were synthesized by chemical polymerization in a hydrochloric acid medium. Due to a large difference in the reactivities of 2-methoxyaniline (OMA) and 3-aminobenzenesulfonic acid (MA), the content of OMA in the copolymers was much higher (over 0.65 of the mole fraction) than in the reaction mixture. Structural characterization of the reaction products was performed using one- (1H, 13C) and two-dimensional (GHSQC and GCOSY) NMR spectroscopy. The NMR data indicated an almost block structure of OMA sequences of variable length separated by shorter sequences of MA units. It was also shown that the incorporation of MA units in the copolymer chains favors the formation of a less oxidized material.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070057
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  • 5
    Digitale Medien
    Digitale Medien
    Relationship between the swelling process and the releases of water soluble agrochemicals from radiation crosslinked acrylamide/itaconic acid copolymers (2000)
    Springer
    Polymer bulletin 45 (2000), S. 287-294 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary An attempt was made in this study to relate the releases of water soluble herbicide (sodium 2,2 dichloropropionate (Dowpon)) and model fertilizers (ammonium nitrate, potassium nitrate and ammonium sulfate) from the cylindrical devices of radiation crosslinked poly(acrylamide/itaconic acid) (AAm/IA) copolymers with the swelling that may effect the release behaviour. AAm/IA copolymers containing agrochemicals are prepared by two different composition of itaconic acid and two different γ-rays doses. The agrochemicals were trapped in the gels by including it in the feed mixture of radiation polymerization. The equilibrium swelling, diffusional exponent, and diffusion and intrinsic diffusion coefficients of the process were obtained. The agrochemical dissolution was determined by conductimetric method. The maximum concentrations of releasing agrochemicals and initial releasing rates were calculated by using of second order kinetics equation. The agrochemical releases appeared to be controlled by swelling. As a result, if AAm/IA hydrogels containing agrochemicals were swelled in water, release of agrochemicals was decreased with the raising of γ-rays doses and itaconic acid quantities in the hydrogel.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070033
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  • 6
    Digitale Medien
    Digitale Medien
    Kinetics of enthalpy relaxation in polymeric glasses (2000)
    Springer
    Polymer bulletin 45 (2000), S. 303-310 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Constitutive equations are developed for the kinetics of enthalpy relaxation in polymeric glasses. An amorphous polymer is treated as an ensemble of cooperatively rearranged regions (CRR). Rearrangement of a CRR is modeled as a hop from one potential well on the energy landscape to another. The probability for changing traps in a hop is determined by the difference between the current and equilibrium concentrations of CRRs. A nonlinear parabolic equation is derived for the distribution function of CRRs. It is applied to predict entropy recovery after a thermal jump. Fair agreement is demonstrated between results of numerical simulation and experimental data for poly(vinyl acetate) and poly(methyl methacrylate) in the vicinity of the glass transition temperature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070035
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  • 7
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of new bivalent tin chelate of 3-hydroxy-2-methyl-4-pyrone and its use as catalyst for polyesterification (2000)
    Springer
    Polymer bulletin 45 (2000), S. 341-344 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary We describe here the synthesis of a new tin chelate Sn(C6H5O3)2.2H2O. The catalytic performance of this chelate is shown for polyesterification reactions involving terephthalic acid and poliols, such as neopentylglygol and trimetilolpropane. The complex is highly active for low molecular weight (Mn= 1700 and Mw= 4500) polymer formation. IR spectra also show free OH in the polymer chain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070005
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  • 8
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of polyimides from 9,10-dialkyloxy-1,2,3,4,5,6,7,8-octahydro-2,3,6,7-anthracenetetracarboxylic-2,3:6,7-dianhydrides and 4,4'-oxydianiline (2000)
    Springer
    Polymer bulletin 45 (2000), S. 311-318 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary New dianhydrides having alkyloxy side chains were synthesized and polymerized with 4,4'-oxydianiline in NMP. Chemically cyclized polyimides were obtained with inherent viscosities of 0.30∼0.84 dL/g range. All the polymers were highly soluble in polar solvent such as NMP at room temperature. TGA pyrograms showed two-step degradation and in DSC thermograms the polymers exhibited Tgs between 124°C and 259°C. Wide-angle X-ray diffractograms revealed very low crystallinity and layered structure, which was better developed in the polymers with longer side chains
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070001
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  • 9
    Digitale Medien
    Digitale Medien
    Hyperbranched poly(arylene ether phosphine oxide)s (2000)
    Springer
    Polymer bulletin 45 (2000), S. 319-326 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary New AB2 and A2B monomers, bis(4-fluorophenyl)-4'-hydroxyphenylphosphine oxide and bis(4-hydroxyphenyl)-4'-fluorophenyl-phosphine oxide were prepared and converted to corresponding hyperbranched poly(arylene ether phosphineoxide)s with hydroxyphenyl and fluorophenyl end functional groups. While the dihydroxy monomer gave a low molecular weight polymer, the difluoro monomer produced a high molecular weight hyperbranched polymer. The glass transition temperature of the obtained polymers was 266°C and 230°C, and 5% weight loss temperature was 491 °C and 391 °C, respectively. The fluorophenyl-terminated hyperbranched polymer was soluble in CHCl3, but the hydroxyphenyl-terminated polymer was not soluble in CHCl3 even though it has lower molecular weight than the fluorophenyl-terminated polymer, indicating that properties of the hyperbranched polymers markedly depend on end functional groups as well as their molecular weight.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070002
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  • 10
    Digitale Medien
    Digitale Medien
    Stereocomplex formation in enantiomeric diblock and triblock copolymers of poly (ɛ-caprolactone) and polylactide (2000)
    Springer
    Polymer bulletin 45 (2000), S. 373-380 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Enantiomeric diblock and triblock copolymers from caprolactone and lactide with various compositions were synthesized using alcohol/tin octoate as initiator system. Stereocomplexes were formed between pairs of enantiomeric block copolymers and their thermal properties examined. The melting temperatures of the crystalline PCL and PLA phases are depending on the composition of block copolymers. A raise of approximately 55°C of the temperature of PLA phase is observed in the blends as a consequence of stereocomplex formation as well in diblock as in triblock copolymers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070010
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  • 11
    Digitale Medien
    Digitale Medien
    Ethylene polymerization with hafnocene adamantolate/MAO system (2000)
    Springer
    Polymer bulletin 45 (2000), S. 365-372 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A new alcoholate of cyclopentadienyl metallocene with voluminous group as ligand substituting chlorine atoms and formula Cp2Hf(OMAd)2 (where Cp = cyclopentadienyl and OMAd = derived of 2-methyl-2-adamantol) was synthesized and employed as catalyst for olefin polymerization. The compound was evaluated in ethylene polymerization activated by methylaluminoxane (MAO) using several experimental conditions. These conditions were determined by a statistic method, and a model for dependent variables like catalyst activity and average molecular weight of polymers were developed. The hafnocene alcoholate produced polyethylenes with molecular weights in the same range of the corresponding metallocene dichloride. The new catalyst system showed high stability under temperature of 100°C. In the presence of H2 as molecular weight controlling agent, the catalyst showed a maximum of activity in the concentration range used.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070009
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  • 12
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of oxyethylene copolymers with phenyl and/or 4,4'-biphenyl structural units in the backbone (2000)
    Springer
    Polymer bulletin 44 (2000), S. 115-122 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary This paper describes the synthesis and characterization of a new series of copolymers with a predominantly poly(ethylene oxide) (PEO) backbone and phenyl and/or 4,4'-biphenyl structural units. Three copolymers, poly[oxyethylene]/poly[oxyphenylene] copolymer (1), poly[oxyethylene] /poly[oxybiphenylene] copolymer (2), and poly[oxyethylene]/poly[oxyphenylene]/poly [oxybiphenylene] copolymer (3), were prepared based on modifications of hydroquinone and/or 4,4'-biphenol copolymerized with dimesylates of various length poly(ethylene glycol)s (PEGs). Depending on their composition and chain length of PEGs used in the polymerization, the copolymers show liquid crystallinity or non-liquid crystallinity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050581
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  • 13
    Digitale Medien
    Digitale Medien
    Radical polymerization of styrene initiate with a new multifunctional iniferter (2000)
    Springer
    Polymer bulletin 44 (2000), S. 123-128 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A new multi-functional iniferter with photo-induced and thermal dissociation group in one molecule, diethyl 2,3-dicyano-2,3-di(p-N,N-diethyldithiocarbamylmethyl)phenylsuccinate(DDDCS), was successfully synthesized. The bulk polymerizations of styrene (St) with DDDCS were studied. The initiation can take place either under UV light irradiation by the reversible C-S bonds dissociation of DDDCS or under heating by the reversible hexa-substituted C-C bond thermally dissociation. The polymerizations have "living" polymerization characteristics under both cases, i.e., the yield and the molecular weight of the resulting polymer increased linearly with increasing reaction time, and the resultant polymers can act as macroiniferter for preparing block copolymer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050582
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  • 14
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of copolymers with alternating 1,4-bis(5'-acetyl-2'-thienyl)benzene or 1,3-bis(5'-acetyl-2'-thienyl)benzene chromophore and disiloxane units (2000)
    Springer
    Polymer bulletin 43 (2000), S. 465-470 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Activated (Ph3P)3RuH2CO (Ru) catalyzed copolymerization of 1,4-bis(5'-acetyl-2'-thienyl)benzene (I) and 1,3-divinyltetramethyldisiloxane (II) yields alt-copoly[3,3,5,5-tetramethyl-4-oxa-3,5-disila-1,7-heptanylene/2',2"-diacetyl-5',5"-(1,4-benzene)-3',3"-bis (thiophenylene)] (III). On the other hand, Ru catalyzed copolymerization of 1,3-bis(5'-acetyl-2'-thienyl)benzene (IV) and II fails. Nevertheless, Ru catalyzed reaction of IV with excess vinylpentamethyldisiloxane (V) yields 1,3-bis(4'-pentamethyldisiloxy-ethyl-5'-acetyl-2'-thienyl)benzene (VI). VI undergoes acid catalyzed siloxane equilibration polymerization to give alt-copoly[3,3,5,5-tetramethyl-4-oxa-3,5-disila-1,7-heptanylene/2',2"-diacetyl-5',5"-(1,3-benzene)-3',3"-bis(thiophenylene)] (VII) and hexamethyldisiloxane. Copolymers III and VII have been characterized.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050002
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  • 15
    Digitale Medien
    Digitale Medien
    Dielectric behavior during sol-gel transition of PEO-PPO-PEO triblock copolymer aqueous solution (2000)
    Springer
    Polymer bulletin 43 (2000), S. 497-504 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050007
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  • 16
    Digitale Medien
    Digitale Medien
    Synthesis of small molar mass perdeuterated polyethylpropylene (d-PEP) as an auxiliary for neutron studies (2000)
    Springer
    Polymer bulletin 43 (2000), S. 485-490 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary An inert non-crystalline cryoprotectant oil was needed as a non-incoherent scattering matrix for neutron studies of solvent containing crystalline materials. This led us to prepare perdeuterated polyethylpropylene (PEP) with a molar mass around 1100 g/mol. On route to this material an improved method for the preparation of isoprene-d8 starting from calcium carbide and acetone-d6 was devised. Subsequent anionic polymerization using t-butyl lithium as initiator resulted in an oligomeric perdeuterated polyisoprene (PI) with an average chain length of approx. 15 monomer units and Mw/Mn: 1.1. This polymer was deuterated with D2 and Pd/C (10%) in cyclohexane to yield the desired perdeutero polymer (PEP-d). The polymer fulfill the important properties that it does not crystallize at low temperature and has a low neutron scattering efficiency.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050005
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  • 17
    Digitale Medien
    Digitale Medien
    Synthesis of polyurethanes containing dioxynitrostilbene as a NLO-chromophore and their properties (2000)
    Springer
    Polymer bulletin 43 (2000), S. 491-495 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary 3,4-Di-(2'-hydroxyethoxy)-4'-nitrostilbene (2) were prepared by the reaction of 2-iodoethanol with 3,4-dihydroxy-4'-nitrostilbene (1). Diol 2 was condensed with 2,4-toluenediisocyanate and 3,3'-dimethoxy-4,4'-biphenylenediisocynate to yield polyurethanes 3 and 4 containing the NLO-chromophore 3,4-dioxy-4'-nitrostilbene. Polymers 3 and 4 were soluble in common organic solvents such as acetone and DMSO. T g value of the resulting polymers was in the range of 109–114°C. Electrooptic coefficient (r33) of the poled polymer films were in the range of 20–25 pm/V at 633 nm. Polymers 3 and 4 showed a thermal stability up to 300°C in TGA thermograms, which is acceptable for NLO device applications.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050006
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  • 18
    Digitale Medien
    Digitale Medien
    Study on the micellization of amphiphilic graft copolymer PS-g-PEO in toluene (2000)
    Springer
    Polymer bulletin 44 (2000), S. 215-222 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: 1 H-NMR, TEM and viscometry. Micelle formation of PS-g-PEO in toluene was strongly dependent on concentration and temperature. An increase in temperature shifted the micelle formation markedly to lower concentration. The micelle was formatted at certain concentration, and it was spherical structure. The viscosity data were analyzed to estimate the cmc value. Key Words:Amphiphilic copolymer, Polymer solution property, Micellization
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050595
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  • 19
    Digitale Medien
    Digitale Medien
    Swelling behavior of poly(α-hydroxy acrylic acid) gel in water/organic solvent mixtures (2000)
    Springer
    Polymer bulletin 44 (2000), S. 209-214 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Swelling behavior of poly(α -hydroxy acrylic acid) (PHA) gel was investigated in water/organic solvent mixtures (acetone, dioxane, dimethyl sulfoxide: DMSO) in comparison with poly(acrylic acid) (PAA) gel. The swelling degrees of PHA and PAA gels significantly decreased with increasing acetone or dioxane content in the mixed solvents, while the deswelling in aqueous DMSO was less apparent. The deswelling region was dependent on the dissociation state of the carboxyl group; when the carboxyl group in the gels was dissociated (-COO), significant deswelling occurred in 30–60 vol.% of acetone or dioxane for PHA gel and in 40–80 vol.% for PAA gel. When the carboxyl group was in an acid form (-COOH) or only slightly dissociated, the deswelling region was 0–30 vol.% for PHA and 80-100 vol.% for PAA. The unique swelling behavior of PHA gel was ascribed to intermolecular hydrogen bonding. Effects of dielectric constant on the swelling are also discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050594
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  • 20
    Digitale Medien
    Digitale Medien
    ATRP grafting from silica surface to create first and second generation of grafts (2000)
    Springer
    Polymer bulletin 44 (2000), S. 223-229 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary (11'-Chlorodimethylsilylundecyl)-2-chloro-2-phenylacetate 2 as an atom transfer radical polymerisation (ATRP) initiator was bound covalently to the surface of silica. ATRP grafting of styrene monomer from the silica surface was achieved and the grafts were detached from the solid particles for analysis. It is shown that after polymerisation of a first generation of grafts and work-up of the thus grafted silica the chain ends of the grafts are still active to initiate a second monomer feed to further chain growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050596
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  • 21
    Digitale Medien
    Digitale Medien
    Preparation and properties of new π-conjugated polyquinoxalines with aromatic fused rings in the side chain (2000)
    Springer
    Polymer bulletin 44 (2000), S. 231-238 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary New π-conjugated polyquinoxalines with aromatic fused rings in their side chain have been prepared. Dehalogenative organometallic polycondensation of 5,8-dibromo[2,3-b]-acenaphthenequinoxaline and 5,8-dibromo[2,3-b]phenanthrenequinoxaline with a zerovalent nickel complex afforded poly([2,3-b]acenaphthenequinoxaline-5,8-diyl) (P(5,8-Qx(ace))) and poly([2,3-b]phenanthrenequinoxaline-5-8-diyl) (P(5,8-Qx(phen))) in high yields. P(5, 8-Qx(ace)) had an [η] value of 0.23 dL g−1 and showed absorption and photoluminescence peaks at 445 and 565 nm, respectively. (P(5,8-Qx(phen))) gave absorption and photoluminescence peaks at 400 and 514 nm, respectively. XRD data indicated formation of ordered structures of the polymers in the solid. Preparation of related copolymer with thiophene is also reported.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050597
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  • 22
    Digitale Medien
    Digitale Medien
    Chemical modifications of functional polybutadienes and their derivatives Part 1. Use of meta isopropenyl-α,α'-methyl benzyl isocyanate (TMI) (2000)
    Springer
    Polymer bulletin 44 (2000), S. 239-246 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The synthesis of a multi(α-methyl styrene) oligomer containing a polybutadienic chain was achieved from the condensation of hydroxytelechelic polybutadiene (HTPB) with meta isopropenyl-α,α'-methyl benzyl isocyanate (TMI). Then, formulations from modified HTPB with various acrylic reactive diluents containing lauryl acrylate and hexane-1,6-diol diacrylate (HDDA) were investigated and compared with classical polyurethanes. Various physical properties (viscosity, shore hardness and gel time) and thermal properties (glass transition and degradation temperatures) were studied and discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050598
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  • 23
    Digitale Medien
    Digitale Medien
    Synthesis of polyurea rotaxanes using a cyclodextrin complex of α,ω-diamine (2000)
    Springer
    Polymer bulletin 44 (2000), S. 247-253 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Polyaddition of α-cyclodextrin (α-CD) inclusion complex of ethylene glycol bis(2-aminoethyl)ether with 4,4'-methylenebis(1-isocyanatobenzene) (MDI) provided a pseudopolyrotaxane. Similar reactions of α-CD inclusion complex of poly(tetrahydrofuran) terminated with 3-aminopropyl groups with MDI and with 1-methyl-2,4-phenylene diisocyanate gave polyurea pseudorotaxane and polyrotaxane, respectively. The 1H NMR spectrum indicates that molar ratios of α-CD to the polyurea chain in polyrotaxanes are 55, 24, and 45%, respectively. Formation of the rotaxane structure was confirmed by X-ray diffraction analysis and GPC measurement. DSC measurement indicates that they show higher glass transition temperature than that of the corresponding CD free polymers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050599
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  • 24
    Digitale Medien
    Digitale Medien
    Synthesis and properties of copolymers from diphenylacetylene having a hexaphenylbenzene moiety (2000)
    Springer
    Polymer bulletin 44 (2000), S. 255-260 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Copolymerization of diphenylacetylene having a hexaphenylbenzene group, 1-[p-(pentaphenyl)phenyl]-2-phenylacetylene (1), with a few other diphenylacetylene derivatives (i.e., diphenylacetylene, 1-phenyl-2-[p-(trimethylsilyl)phenyl] acetylene, 1-phenyl-2-[p-n-octylphenyl]acetylene, (2a–c, respectively) and properties of the formed copolymers were investigated. No polymer was obtained in homopolymerization of 1 with TaCl5-n-Bu4Sn catalyst owing to steric hindrance. On the other hand, copolymerization with 2a–c proceeded at various feed ratios to give copolymers in moderate yields. Copoly(1/2a) (feed ratio 25/75) was soluble in toluene and CHCl3 and its weight-average molecular weight (M w) was ca. 31×104 and relatively high. Copoly(1/2b) and copoly(1/2c) (both feed ratios 5/95) were soluble in common organic solvents, and had a large M w up to ca. 1×106. These copolymers were yellow to orange solids. Oxidative cyclodehydrogenation of hexaphenylbenzene groups in copoly(1/2a) was attempted in order to convert them into more conjugated groups.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050600
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  • 25
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of N-phenylmaleimide-methylvinylisocyanate copolymers with polystyrene side chains (2000)
    Springer
    Polymer bulletin 44 (2000), S. 261-268 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary N-Substitued maleimide-methylvinylisocyanate copolymers with high glass transition temperature (Tg) was prepared and reacted with 4-hydroxy TEMPO (4-hydroxy-2,2,6,6-tetramethyl piperidinoxy) to yield polymers possessing stable radical at the side chain. The resulting polymers behaved as polymeric counter radicals for the radical polymerization of styrene. Thus, stable free radical mediated polymerization at the side chain was achieved. The resulting graft copolymers were characterized by spectral and thermal analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050601
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  • 26
    Digitale Medien
    Digitale Medien
    Temperature sensitive polymers based on 2-(dimethyl maleinimido)-N-ethyl-acrylamide: Copolymers with N-isopropylacrylamide (2000)
    Springer
    Polymer bulletin 44 (2000), S. 269-276 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Temperature sensitive polymers with pendant dimethyl maleinimide side groups were prepared by the copolymerization of N-isopropylacrylamide (NIPAAm) with varying amounts of a functional N-substituted acrylamide (2-(dimethyl maleinimido)-N-ethyl-acrylamide, DMIAAm). The polymers were characterized by 1H-NMR, IR, DSC and TGA. Their relative reactivity ratios have been determined. Aqueous solutions of the copolymers showed lower critical solution temperature behaviour (LCST). The phase transition temperatures of the aqueous solutions of these copolymers decreased with increasing comonomer content and disappeared at DMIAAm contents at or above 15.9 mol-%.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050602
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  • 27
    Digitale Medien
    Digitale Medien
    Fluorescent chemosensor for metal ions using a polymer having pendant pyridylbenzoxazole groups (2000)
    Springer
    Polymer bulletin 44 (2000), S. 79-84 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A polymer having fluorescent pyridylbenzoxazole groups has been prepared for the purpose of detecting of metal ions. Metal ions such as Co2+, Ni2+, Cu2+ and Fe2+ were found to coordinate with the bipyridyl-like fluorescent benzoxazole chromophores. Among the metal ions investigated, the Fe2+ ion was shown to be the most effective in terms of its fluorescence quenching ability. The addition of a metal scavenger 2,2'-dipyridyl to the metal ion-quenched polymer solution resulted in the recovery of the fluorescence.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050576
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  • 28
    Digitale Medien
    Digitale Medien
    Fine structure in cholesteric fingerprint texture observed by scanning electron microscopy (2000)
    Springer
    Polymer bulletin 44 (2000), S. 85-91 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The fine structure in some cholesteric fingerprint textures of cyanoethyl chitosan (CNCS)/acrylic acid solution and photo-solidified CNCS/polyacrylic acid composite film was studied using scanning electron microscopy (SEM), small angle light scattering (SALS) and polarizing optical microscopy (POM). Permanganic etching was developed to reveal the cholesteric liquid crystalline textures in the composite films. A schematic model was presented to explain this kind of fine structure. The directors within each cholesteric molecular layer did not orient in nematic-like order, but varied their orientation by an ill-defined period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050577
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  • 29
    Digitale Medien
    Digitale Medien
    Thermal stability of polyaniline (2000)
    Springer
    Polymer bulletin 44 (2000), S. 101-108 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Among conducting polymers with metallic characteristics, polyaniline (PANI) is claimed to have one of the highest environmental stability. From an industrial point of view it would be useful to be able to thermally process this material into useful products using conventional techniques such as extrusion, stretching, rolling, etc., which generally are carried out at elevated temperatures. Somewhat surprisingly, relatively few studies have addressed the thermal stability of PANI, in particular that of the non-protonated emeraldine base form. Therefore, a study of the thermal properties was performed to examine the thermal stability of this material and to identify the optimum processing and maximum application temperatures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050579
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  • 30
    Digitale Medien
    Digitale Medien
    Inverse gas chromatographic observation of thermodynamic interaction between poly (vinylidene fluoride) and organic solvents (2000)
    Springer
    Polymer bulletin 44 (2000), S. 93-100 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Inverse gas chromatography (IGC) has been applied to observe the interaction between poly(vinylidene fluoride) (PVDF) and organic solvent systems under conditions approaching infinite dilution of the volatile component. The specific retention volumes (Vg 0) were calculated from the retention volumes of the PVDF/solvent systems. The retention diagrams (RDs) which were plotted as ln Vg 0 vs. reciprocal temperature, corresponded with the thermodynamic behavior of PVDF. PVDF dissolves well in carbonyl-containing solvents at high temperatures. In these systems, the solution is converted easily to a thermoreversible gel by standing at room temperature. The Flory-Huggins interaction parameter (χ12) and molar heat of sorption of probe absorbed by the amorphous part of PVDF (Δ H1 s) calculated from the retention values indicated that the characteristics of the interaction between PVDF and the solvent (probe) varied with temperature and probe properties. The results of IGC of PVDF/solvent systems were discussed in relation to the dissolution and gelation behavior of PVDF.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050578
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  • 31
    Digitale Medien
    Digitale Medien
    Equilibrium swelling and mechanical properties of hydrogels of acrylamide and itaconic acid or its esters (2000)
    Springer
    Polymer bulletin 44 (2000), S. 109-114 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The equilibrium swelling and the plateau elastic modulus of a family of hydrogels made by the polymerization of acrylamide with itaconic acid or some of its esters were investigated as a function of composition and crosslinking degree to find materials with satisfactory swelling and elastic properties. We show that an appropriate selection of the comonomers and the concentration of the crosslinking agent is very important to produce hydrogels with large swelling capacity and good mechanical attributes. Tailoring of mechanical properties and swelling can also be achieved by this method.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050580
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  • 32
    Digitale Medien
    Digitale Medien
    Characterisation of gel permeation chromatography column by fractal geometry (2000)
    Springer
    Polymer bulletin 44 (2000), S. 525-532 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary General aspects of fractal geometry are treated, and a mathematic model for characterisation of chromatographic gel behaviour is presented. The fractal dimension of the porous gel within a Waters Styragel HT 5 chromatography column, df= 2.3, as well as the linear dimension of pores, L = 0.3 μm, have been determined.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070074
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  • 33
    Digitale Medien
    Digitale Medien
    Synthesis of star-shaped poly(vinyl ether)s by living cationic polymerization: Pathway for formation of star-shaped polymers via polymer linking reactions (2000)
    Springer
    Polymer bulletin 44 (2000), S. 485-492 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary: Star-shaped polymers of isobutyl vinyl ether (IBVE) with a microgel core of an aliphatic divinyl ether (2) were synthesized in high yield on the basis of the living cationic polymerization with the HCl/ZnCl2 initiating system. GPC analysis demonstrated that linear coupling products ("two-armed" polymers) and three-armed star polymers formed during the early stages of the linking reaction, and that subsequent coupling reactions between such low molecular weight star polymers gave star-shaped polymers with more arms. The number of arms ranged from 5 to 22, which increased with increasing [2]0/[P*] ratio and/or shortening the arm chain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070069
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  • 34
    Digitale Medien
    Digitale Medien
    Molecularly imprinted polyamide membranes for chiral recognition (2000)
    Springer
    Polymer bulletin 44 (2000), S. 517-524 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: SUMMARY Molecularly imprinted polymeric membranes were prepared from amorphous poly(hexamethylene terephthalamide/isophthalamide). Membranes imprinted by Z-D-Glu recognize the D-isomer, of which absolute configuration is the same as that of the print molecule, in preference to the corresponding L-isomer, and vice versa. The amino acid preferentially adsorbed by the membrane was also selectively permeated by electrodialysis. An optimum separation factor of 2.0 was reached at the applied potential difference of 2.0 V.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070073
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  • 35
    Digitale Medien
    Digitale Medien
    Binding of some dyes onto crosslinked poly (N-vinylpyrrolidone) (2000)
    Springer
    Polymer bulletin 44 (2000), S. 501-508 
    Details
    ISSN: 1436-2449
    Schlagwort(e): Key words: crosslinked poly(N-vinylpyrrolidone), anionic dye, binding, adsorption.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Bindings of some anionic dyes containing sulfonyl group(s), namely, Acid Blue 74 (AB-74), Acid Orange 7 (AO-7), Acid Green 1 (AG-1), Direct Blue 53 (DB-53), and Calconcarboxylic acid (CCA) onto crosslinked poly(N-vinylpyrrolidone) (CPVP) have been investigated using adsorption isotherm parameter. The dyes were linked positively charged on the tertiary nitrogen atom on the pyrrolidone ring in polymer chain resulting keto-enol tautomerism from sulfonyl group on the benzene ring in the dyes molecules. In the experiments of adsorption, L (Langmuir) type adsorption in the Giles classification system was found. Monolayer coverages (n) of polymer/dye system were founds by "B point" methods. Adsorption studies indicated that monolayer coverages of CPVP by the anionic dyes containing sulfonyl group(s) were increased with following order; CCA 〉 AG-1 〉〉 DB-53 〉 AO-7 〉 AB-74.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070071
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  • 36
    Digitale Medien
    Digitale Medien
    Stereocomplex formation in atactic poly(methyl methacrylate) I. Effect of solvents (2000)
    Springer
    Polymer bulletin 44 (2000), S. 533-538 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The stereocomplexation in three kinds of atactic poly (methyl methacrylate) (a-PMMA) films with different tacticities isolated from acetone, benzene, and chloroform solution was studied by Fourier transformation infrared (FTIR) and differential calorimetry scanning (DSC) techniques. Based on the results of infrared spectra, it could be deduced that stereocomplexes were formed in the films cast from acetone and benzene solutions with the increase in the population of trans-trans (tt) conformation of the backbone of i- and s-segments. It was assumed that the stereocomplexes formed by the interactions between i- and s-segments, possibly including intramolecular complexation. The stereocomplexation was also confirmed by the evidence of a endotherm with melt temperature over the range 180°C to 200°C, which was corresponded to the melting stereocomplex aggregates formed in the solutions and stabilized by the solvent molecules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070075
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  • 37
    Digitale Medien
    Digitale Medien
    Investigation of polymerization parameters affecting dopamine selectivity of a polymeric membrane (2000)
    Springer
    Polymer bulletin 44 (2000), S. 547-553 
    Details
    ISSN: 1436-2449
    Schlagwort(e): Key words: permselective polymeric membrane; dopamine sensor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary By means of electrochemical oxidative polymerization, poly (1,3-phenylenediamine) films on a gold electrode were prepared at a potential of 0.8 V. The permeation properties of polymeric films at the different thickness were investigated by cyclic and differential pulse voltammetry techniques. Voltammetric studies showed that polymeric film at the 1.2 mC thickness exhibited selective permeation for dopamine while rejecting ascorbic acid. Then, all the polymerization parameters affecting the permselective characteristics were systematically investigated and the optimal values were determined. Moreover, stability of polymeric membrane was examined. The results showed that polymeric membrane, owing to permselective character, could be used as a dopamine selective membrane.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070077
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  • 38
    Digitale Medien
    Digitale Medien
    Characterization of novel liquid crystalline polymers of polyacetylenes having a comb-like structure via SEC/RI/RALLS/DV (2000)
    Springer
    Polymer bulletin 44 (2000), S. 539-546 
    Details
    ISSN: 1436-2449
    Schlagwort(e): Key Words: multi-detector SEC, liquid crystalline polymer, polyacetylene, comb-like structure, characteristic ratio
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Novel liquid crystalline polymers comprised of polyacetylenes having a comb-like structure were studied by size exclusion chromatography (SEC) with refractive index, right angle laser light scattering, and differential viscometry detectors (RI/RALLS/DV). This combination of SEC detectors is known as triple detector SEC, or simply SEC3. Based upon the data generated for these materials, the relationship between molecular size and the polymer structure was investigated, SEC universal calibration was shown to be valid, Flory's characteristic ratio (C∞) was estimated, and the effect of the size of the side group on chain flexibility was elucidated. These results demonstrate that the technique of SEC3 is a powerful mean for characterizing polymers that cannot be effectively characterized by conventional SEC, such as the liquid crystalline polymers of this study.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070076
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  • 39
    Digitale Medien
    Digitale Medien
    Telomerization of acrylic acid with thioglycolic acid Effect of the solvent on the CT value (2000)
    Springer
    Polymer bulletin 44 (2000), S. 569-576 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The telomerization of acrylic acid (AA) with thioglycolic acid (TGA) initiated with 2,2'-azobisisobutyronitrile (AIBN) was first investigated in organic medium (THF, 65°C). The kinetic study of this telomerization led to the determination of the TGA transfer constant (CT= 3,2). Then, the same study was performed both in aqueous medium and in water / THF mixtures. From these works it is emphasised that the nature of the solvent plays an important role on the transfer constant. Thus, the value of CT decreased from CT= 3,2 in THF to 0,5 in water. By this way, the "ideal" case of telomerization (CT= 1) was reached for a mixture of solvents: water / THF (80%, 20%, v/v).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070080
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  • 40
    Digitale Medien
    Digitale Medien
    Interactions of linear and cross-linked polyacrylic acid with polyvinyl ether of ethyleneglycol in some aliphatic alcohols (2000)
    Springer
    Polymer bulletin 44 (2000), S. 563-568 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The interaction of linear and cross-linked polyacrylic acid (PAA) with polyvinyl ether of ethyleneglycol (PVEEG) has been studied in ethanol, isopropanol and their mixture. Formation of interpolymer complexes (IPC) in solutions is accompanied by aggregation of compact particles. Gels of PAA undergo shrinking in solutions of PVEEG.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070079
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  • 41
    Digitale Medien
    Digitale Medien
    Effect of interphase interactions on the dielectric behaviour of polycarbonate/poly(styrene-co-acrylonitrile) blends (2000)
    Springer
    Polymer bulletin 44 (2000), S. 555-562 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Frequency and temperature dependences of the complex permittivity ɛ* (=ɛ′−i ɛ″, ɛ′ is the real and ɛ″ imaginary component, respectively) were investigated for blends of polycarbonate/poly(styrene-co-acrylonitrile) (PC/SAN). In the blends, two α-processes corresponding to the main transitions of PC and SAN were found; for SAN at concentrations c SAN≥ 20 wt% and for PC for c PC≥ 40 wt%. The Havriliak-Negami shape parameters describing the frequency dependence of ɛ′ and ɛ″ are virtually independent of temperature and composition. Slight shift of temperature or frequency positions of α-processes found for blends from those found for neat polymers with composition of blends indicated partial miscibility of components. The concentration dependences of ɛ′ and ɛ″ at low frequencies and high temperatures could be described with the Böttcher equation from which it followed that percolation threshold takes place for SAN inclusions at c SAN≈ 30 wt%. Both the reduced dielectric strength ΔɛT and the reduced Onsager term O t/c SAN (or O t/c PC) in dependence on the blend composition could be qualitatively described by the Böttcher equation as well.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070078
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  • 42
    Digitale Medien
    Digitale Medien
    Dynamic mechanical study of the transition from swollen particles to hydrogel caused by neutralization (2000)
    Springer
    Polymer bulletin 44 (2000), S. 585-592 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The copolymer of 2-(2-carboxybenzoyloxy)ethyl methacrylate (CEM) with butyl methacrylate (BMA) (BMA/CEM = 40/60 wt.) and terpolymers CEM/BMA/ 2-hydroxyethyl methacrylate (HEMA) ((BMA + HEMA)/CEM = 40/60 wt.; HEMA/BMA = 35/5, 30/10, 20/20 and 10/30) were prepared by emulsion radical copolymerization in water in the presence of sodium dodecyl sulfate and their dynamic mechanical behaviour was investigated as a function of the degree of neutralization α. Main attention was devoted to the transition from swollen particles to physical gel with increasing degree of neutralization and to the structure of formed hydrogels. From the results it followed: (a) the transition from swollen particles to the gel state occurs in a narrow neutralization interval at α∼ 0.45 for BMA/CEM copolymer; increasing the HEMA content shifts the transition to lower α values; (b) with increasing shear strain γ, the hydrogels passed from the gel to liquid state and this transition at the critical strain γc, was reversible; (c) junctions in the gel state are probably formed by the hydrophobic interactions of the ends of CEM units which form clusters and the junction concentration is independent of the HEMA content and degree of neutralization α; (d) increasing degree of neutralization α and the HEMA content (increasing polarity of the system) stabilizes the junctions and the critical γc values increase; (e) the values of the low-strain storage G′0 and loss G″0 moduli together with critical strains γc did not depend on angular frequnecy ω in the interval 10−1− 10 rad/s.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070082
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  • 43
    Digitale Medien
    Digitale Medien
    Uranyl ion adsorptivity of N-vinyl 2-pyrrolidone/acrylonitrile copolymeric hydrogels containing amidoxime groups (2000)
    Springer
    Polymer bulletin 44 (2000), S. 593-600 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary N-vinyl 2-pyrrolidone (VP) / Acrylonitrile (AN) copolymeric hydrogels were synthesized by using γ-radiation and amidoximated for the purpose of uranyl ion adsorption. Optimum amidoximation time was determined by following the uranyl ion, UO2 2+, adsorption capacity. The adsorption of amidoximated copolymers was studied from different uranyl ion solutions (1000–1850 ppm). The results of all adsorption studies showed that the interaction between UO2 2+ and amidoxime groups comply with Langmuir type isotherm. The adsorption capacity was found as 0.54 g UO2 2+ /g dry amidoximated copolymeric hydrogels. From the stoichiometric calculations, it was found that the bonding between UO2 2+ and amidoxime groups is 1 to 4.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070083
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  • 44
    Digitale Medien
    Digitale Medien
    Phase behavior of electron beam cured and uncured propoxylated glyceroltriacrylate/E7 mixtures (2000)
    Springer
    Polymer bulletin 44 (2000), S. 577-584 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The phase properties of uncured and electron beam cured propoxylated Glyceroltriacrylate (GPTA)/E7 mixtures are investigated using polarized optical microscopy and differential scanning calorimetry. The cured samples were prepared by polymerization/crosslinking reactions with controlled dose and dose rate by means of electron beam irradiation. The experimental phase diagram of cured GPTA/E7 mixtures was successfully analyzed using a model based on the Flory-Rehner elastic free energy supplemented with the Maier-Saupe free energy of nematic order. The data corresponding to the uncured samples were successfully interpreted combining the Flory-Huggins theory of isotropic mixing and the Maier-Saupe theory of nematic order.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070081
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  • 45
    Digitale Medien
    Digitale Medien
    Formation of IPN organic-inorganic polymer hybrids utilizing the photodimerization of thymine (2000)
    Springer
    Polymer bulletin 45 (2000), S. 9-16 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Formation of an interpenetrating polymer network (IPN) composed of organic polymer gel and silica gel in the form of polymer hybrids was conducted by utilizing the photodimerization of thymine bases. Thymine-modified poly(2-methyl-2-oxazoline) (POZO-T) was synthesized by the condensation reaction of partially hydrolyzed polyoxazoline and 1-(2-carboxyethyl)thymine. Organic-inorganic polymer hybrids were prepared from POZO-T and tetramethoxysilane (TMOS). Transparent and homogeneous polymer hybrids could be obtained. The photodimerization and the reverse reaction of thymine in the polymer hybrids were monitored by the UV absorption spectroscopy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070050
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  • 46
    Digitale Medien
    Digitale Medien
    Hyperbranched aromatic epoxies in the design of adhesive materials (2000)
    Springer
    Polymer bulletin 45 (2000), S. 1-7 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The use of hyperbranched aromatic epoxy polymer 2 (HARE) as a component in various adhesion experiments has been demonstrated. Two different modes of curing were tested, including a photoinitiated cationic curing process and a polyfunctional amine curing process. These processes gave flexible films that showed good adhesion to nylon, steel, and glass. Furthermore, blends of HARE and the commercial epoxy resin bisphenol F diglycidyl ether (BPFG) were cured with 2-ethyl-4-methylimidazole (EMI) at 150 °C on lap-shear assemblies. These cured assemblies displayed adhesive strengths in the range of 15 MPa over a broad range of HARE/BPFG weight ratios.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070049
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  • 47
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of poly(meth)acrylates containing tricyanocyclopropane ring for piezoelectric applications (2000)
    Springer
    Polymer bulletin 45 (2000), S. 17-23 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary p-(2,2,3-Tricyano-3-carbomethoxycyclopropyl)phenoxyethyl acrylate (5a) and p-(2,2,3-tricyano-3-carbomethoxycyclopropyl)phynoxyethyl methacrylate (5b) were prepared by the reactions of bromomalononitrile with methyl p-(2-acryloyloxyethoxy)benzylidene-cyanoacetate (4a) and methyl p-(2-methacryloyloxyethoxy)benzylidenecyanoacetate (4b), respectively. Monomers 5a and 5b were polymerized with free-radical initiators to obtain the polymers with multicyanocyclopropane functionalities in the pendant group. The resulting polymers 6a and 6b were soluble in acetone and the inherent viscosities were in the range of 0.20–0.25 dL/g. Solution-cast films showed T g values in the range of 130–150°C and piezoelectric coeffcients (d31) of the poled films were 1.5–1.6 pC/N, which are acceptable for piezoelectric device applications.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070051
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  • 48
    Digitale Medien
    Digitale Medien
    Novel preparation of poly(oxy-1,2-phenylene-oxymethylene) (2000)
    Springer
    Polymer bulletin 45 (2000), S. 25-29 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary 7-Iodo-1-oxaspiro[2.5]octa-5,7-dien-4-one undergoes melt polymerization to yield poly(oxy-4-iodo-1,2-phenylene-oxymethylene). The polymerization involved a nucleophilic attack of the terminal hydroxy group of the growing polymer chain at the methylene carbon in oxirane followed by cleavage of the oxirane ring and simultaneous aromatization of cyclohexadienone to generate a new phenol to continue the polymerization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070052
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  • 49
    Digitale Medien
    Digitale Medien
    Steric and electronic effects on mesophase stability of segmented liquid crystalline polymers with arylazomethine pendant groups (2000)
    Springer
    Polymer bulletin 45 (2000), S. 31-38 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The synthesis and thermotropic behavior are reported for a series of polyesters, 1, and its model compounds, 2, which bear a N-arylazomethine pendant group with para-substituents in order to evaluate electronic and steric effects on mesophase stability of segmented LCP with Y-shaped mesogens. Substituent effects on these polymer series and model compound series are dominated by steric effects. The results suggest that due to the conformational flexibility of the azomethine group this type of macromolecules cannot be strictly considered as Y-shaped segmented liquid crystal polymers. It was also concluded that when steric effects are predominant the mesomorphic behavior of model compounds can be used to estimate polymer nematic mesomorphic properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070053
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  • 50
    Digitale Medien
    Digitale Medien
    Self-aggregates of poly(aspartic acid) grafted with long alkyl chains (2000)
    Springer
    Polymer bulletin 45 (2000), S. 39-43 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Biodegradable poly(aspartic acid) (PASP) containing octadecyl chain grafts has been synthesized by thermal polycondensation of aspartic acid, aminolysis by octadecylamine, and followed by hydrolysis of remaining succinimide in polymer backbone. The sonicated suspension formed self-aggregates in aqueous solution. Size exclusion chromatography and dynamic light scattering indicated that self-aggregates became compact and particle size was reduced as increasing the amount of substituted octadecyl chains. In the case of low degree of substitution, self-aggregates assembled loosely due to low hydrophobic interaction. In the concentration range of 0.05–1.0%, the stability of aggregates was maintained due to effective hydrophobic interaction and electrostatic repulsion. Below pH 3.2, macroscopic phase-separation appeared in aqueous solution due to attraction of protonated PASP backbone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070054
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  • 51
    Digitale Medien
    Digitale Medien
    Living polymerization of methyl methacrylate by novel samarium-based trifunctional initiator (2000)
    Springer
    Polymer bulletin 45 (2000), S. 231-236 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A novel trifunctional samarium enolate, prepared in situ by the reduction of 1,3,5-tris(2-bromoisobutyroyloxymethyl)benzene with SmI2, has proven to initiate the polymerization of methyl methacrylate (MMA). Characterization of the polymer by 1H NMR and GPC clearly supported the formation of a star-shaped tri-armed poly(MMA). The resulting star-shaped poly(MMA) possessed narrow molecular weight distribution, and its molecular weight agreed well with the theoretical value, which reveals the quantitative initiation efficiency.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070025
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  • 52
    Digitale Medien
    Digitale Medien
    Synthesis, characterization, and oxygen permeability of homo- and copolymers from p-[tris(trimethylsilyl)silyl]-phenylacetylene (2000)
    Springer
    Polymer bulletin 45 (2000), S. 215-221 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Homopolymerization of p-[tris(trimethylsilyl)silyl]phenylacetylene [p(Me3Si)3SiPA] by Rh catalyst provided insoluble polymer. On the other hand, copolymerization of p(Me3Si)3SiPA with p-(trimethylsilyl)phenylacetylene (pMe3SiPA) at 80:20, 50:50, and 20:80 feed ratios afforded high molecular weight copolymers (M w 〉 1×106), all of which were soluble in common solvents such as toluene and chloroform. The mole ratios of p(Me3Si)3SiPA to pMe3SiPA unit in copolymers were close to those in the feeds. The oxygen permeability increased monotonously with increasing p(Me3Si)3SiPA content of copolymer in correspondence with fractional free volume; the value of the copolymer for the 80:20 feed ratio reached 770 barrers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00006835
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  • 53
    Digitale Medien
    Digitale Medien
    Secondary structural analysis in the solid state for analogous sequential polypeptides of glycine-rich sequence of spider dragline silk (2000)
    Springer
    Polymer bulletin 45 (2000), S. 237-244 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Four sequential copolypeptides poly(X-Gly-Gly) with X being Ala, Tyr, Gln, or Leu were prepared as a model of glycine-rich sequence of dragline spider silk produced by Nephila clavipes and their secondary structures in the solid state were characterized by FT-IR spectroscopy. Poly(Tyr-Gly-Gly), poly(Gln-Gly-Gly), and poly(Ala-Gly-Gly) form the β-sheet structures, whereas poly(Leu-Gly-Gly) existed as a disordered conformation as a cast film from formic acid. These results indicated that X-Gly-Gly sequences with Tyr, Gln, and Ala could contribute to the formation of the β-sheet structure in glycine-rich sequence.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070026
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  • 54
    Digitale Medien
    Digitale Medien
    Functionalization of low molecular weight atactic polypropylene Part II. Thermal and molecular weight studies (2000)
    Springer
    Polymer bulletin 45 (2000), S. 245-252 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Number average molecular weight (Mn), intrinsic viscosity ([η]) and glass transition temperature (Tg) of low molecular weight atactic polypropylene (APP) grafted with 4-allyl-1,2-dimethoxybenzene (DMAB), 4-allyl-2-methoxyphenol (eugenol) and 4-propenylanisole (trans-anethole) in the presence of dicumyl peroxide (DCP) at 170°C were determined. The influences of reaction time, concentration and extent of grafting on Mn, [η] and Tg of APP were examined. The data were discussed with the mechanism of grafting reactions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070027
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  • 55
    Digitale Medien
    Digitale Medien
    Polyelectrolyte-Cu(II) interactions studied by cyclic voltammetry (2000)
    Springer
    Polymer bulletin 45 (2000), S. 259-265 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: SUMMARY The polymer-metal ion interactions were studied by cyclic voltammetry. These were carried out with poly(acrylic acid)-Cu(II) and poly(vinylsulfonic acid)-Cu(II) systems at different pH. At low pH, the polymer was adsorbed on the electrode surface increasing the irreversibility of the Cu2+/Cu(s) redox system. At pH 2.7, it was possible to demonstrate that the interaction between Cu(II) and poly(vinylsulfonic acid) is basically electrostatic and with poly(acrylic acid) a complex formation also exists.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070029
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  • 56
    Digitale Medien
    Digitale Medien
    Phase behavior of poly (pyromellitimide)s having flexible (n-alkyloxy)methyl side chains (2000)
    Springer
    Polymer bulletin 45 (2000), S. 253-258 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Phase behavior of poly(pyromellitimide)s having (n-alkyloxy)methyl side chains (-CH2OCmH2m+1, m=4, 6, 8) has been studied by wide angle X-ray scattering, differential scanning calorimetry and 13C solid-state NMR. While there are no observable transitions in the polymers bearing short side chain(m=4, 6), there is one transition in the polymer bearing the longest side chain(m=8), which is assigned to mesophase-mesophase transition. All the samples show layered mesophase at room temperature, in which the side chains are amorphous but the main chains form two-dimensional crystals in each layer. In the polymer bearing the longest side chain(m=8), it shows another layered mesophase at high temperature. In the high temperature mesophase, the main chains do not form two-dimensional crystals in each layer; only the lateral packing of the main chains remains undisrupted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070028
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  • 57
    Digitale Medien
    Digitale Medien
    Effect of steric hinderance on junction properties of poly (3-alkylthiophene)s based schottky diodes (2000)
    Springer
    Polymer bulletin 45 (2000), S. 267-274 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: n -hexylthiophene), and metals, such as, In, Ag, Al, Sn, etc. The polymers were synthesised chemically using ferric chloride as catalyst. The electrical properties of the devices have been studied by current-voltage (I-V) and capacitance-voltage (C-V) measurements. Junction parameters such as ideality factor (n) and barrier height (χ) have been calculated on the basis of thermoionic emission theory. Better performance of P3cHT/metal diode, compared to P3nHT was attributed to the steric effects produced by cyclohexyl unit present in the polymer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070030
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  • 58
    Digitale Medien
    Digitale Medien
    Free Volume of cis-1,4 polyisoprene/polybutadiene blends (2000)
    Springer
    Polymer bulletin 45 (2000), S. 275-279 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The number and radius of molecular order free space present in polybutadiene (PBD)/polyisoprene (PIP) blend were observed by positron life-time measurement, and apparent free volume fraction was estimated. The changes in the number and radius of the free space were not represented to be a linear function of blend composition. The apparent free volume fraction increased by mixing PBD with PIP and was approximated by a concave curve depicted against blend composition, even though the excess volume of mixing was proved to be negative. The change in the apparent free volume fraction was related to the variation of thermal expansion coefficient on blend composition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/PL00006836
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  • 59
    Digitale Medien
    Digitale Medien
    In situ photon transmission technique for monitoring phase separation in real time during gelation (2000)
    Springer
    Polymer bulletin 45 (2000), S. 281-285 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary In situ, real time photon transmission technique was used to monitor the formation of heterogeneities during the free-radical crosslinking polymerization of acrylamide in the presence of N,N'-methylenebis(acrylamide) (BAAm) as a crosslinker. Two different gelation experiments were performed with various BAAm and water contents separately at room temperature. It was observed that the transmitted photon intensity, I tr decreases dramatically at a certain time, in both type of experiments during the gel formation process from interconnected microgels. Decrease in I tr was interpreted in terms of phase separation during gelation. The extent of phase separation was measured depending on the crosslinker content and on the degree of monomer dilution during the gel formation process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070032
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  • 60
    Digitale Medien
    Digitale Medien
    Morphological stability of postconsumer PET/HDPE blends (2000)
    Springer
    Polymer bulletin 45 (2000), S. 295-302 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The morphological stability and the mechanical properties of postconsumer polyethylene terephthalate (PET) and high density polyethylene (HDPE), at different composition with and without compatibilizer were investigated. The blends were prepared in an internal mixer and in a twin screw-extruder at different stretching ratio. For uncompatibilized blends, (previously prepared by extrusion), the particle size of the dispersed phase increases after being reprocessed in an internal mixer. However, in the case of compatibilized blend the particle size remains constant. Consequently, the compatibilizer reduces interfacial mobility, coalescence effects and stabilizes the morphology. The mechanical properties are also modified by the presence of the compatibilizer, mainly the elongation at break.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070034
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  • 61
    Digitale Medien
    Digitale Medien
    Living polymerization and block copolymerization of various ring-substituted phenylacetylenes by rhodium-based ternary catalyst (2000)
    Springer
    Polymer bulletin 45 (2000), S. 335-339 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Polymerization of several ring-substituted phenylacetylenes, i.e. p-methoxy-, p-methyl-, p-chloro-, and p-methoxycarbonylphenylacetylenes by the [(nbd)RhCl]2/Ph2C=CPhLi/Ph3P ternary catalyst proceeded in a living fashion to quantitatively provide polymers with low polydispersity indices (M w/M n 1.04–1.18). The initiation efficiencies were virtually quantitative. Block copolymerizations proceeded regardless of the combinations and addition orders of these monomers to selectively form the corresponding block copolymers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070004
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  • 62
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of new poly(arylene ether 1,3,4-oxadiazole)s based on dihydroxynaphthalene isomers (2000)
    Springer
    Polymer bulletin 45 (2000), S. 345-350 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A series of new poly(arylene ether 1,3,4-oxadiazole)s has been obtained starting from a difluorosubstituted monomer containing 1,3,4-oxadiazole rings and some dihydroxynaphthalene isomers. The polymers have been prepared by polycondensation in solution and have been obtained in quantitative yield. They had inherent viscosity from 0.2 to 0.82 dL/g, showed good thermal stability (10% weight loss temperatures in nitrogen and air were above 460 and 450°C, respectively) and high glass transition temperatures (in the range of 197–232°C). The polymers were characterized by elemental and infrared analyses, GPC and wide angle X-ray diffraction.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070006
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  • 63
    Digitale Medien
    Digitale Medien
    Synthesis of vinyloxy phosphorus monomers from the enolate of acetaldehyde (2000)
    Springer
    Polymer bulletin 45 (2000), S. 359-364 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A simple synthetic procedure for vinyloxy phosphorus monomers involves the reaction of the enolate of acetaldehyde, obtained from the cycloreversion of tetrahydrofuran in the presence of n-butyllithium, with chlorophosphites or phosphorochloridates leading to vinyl phosphites or vinyl phosphates, respectively, in high yield and purity.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070008
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  • 64
    Digitale Medien
    Digitale Medien
    Novel copolymers of trisubstituted ethylenes with styrene — 7. Methyl 2-cyano-3-dihalophenyl-2-propenoates (2000)
    Springer
    Polymer bulletin 45 (2000), S. 351-357 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Methyl 2-cyano-3-dihalophenyl-2-propenoates, R2C6H3CH=C(CN)CO2CH3 (R2= 2,4-difluoro, 2,5-difluoro, 2,6-difluoro, 3,4-difluoro, 3,5-difluoro, and 2-chloro-6-fluoro), were prepared by the piperidine catalyzed Knoevenagel condensation of corresponding disubstituted benzaldehydes and methyl cyanoacetate. Novel copolymers of the propenoates and styrene were prepared at equimolar monomer feed by solution copolymerization in the presence of a radical initiator. The order of relative reactivity (1/r 1) was 2,5-difluoro (2.11) 〉 2,6-difluoro (1.84) 〉 3,5-difluoro (1.71) 〉 2,4-difluoro (1.4) 〉 3,4-difluoro (0.65) 〉 2-chloro-6-fluoro (0.59). The copolymers were characterized by IR, 1H and 13C NMR, GPC, DSC and TGA. High glass transition temperatures of the copolymers compared that of polystyrene indicates a substantial decrease in chain mobility of the copolymers due to the high dipolar character of the trisubstituted ethylene monomer unit.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070007
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  • 65
    Digitale Medien
    Digitale Medien
    Glass transition temperature and thermal degradation of N-2-acryloyloxyethyl phthalimide copolymers (2000)
    Springer
    Polymer bulletin 45 (2000), S. 397-404 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Copolymers of methyl methacrylate, MMA, with N-2-acryloyloxyethyl phthalimide, AEP, have been prepared by free radical polymerization. Glass transition temperatures, Tg; and thermal degradation of homo and copolymers have been determined by differential scanning calorimetry and by thermogravimetric analysis. Johnston's equation, which considers the influence of monomeric units' distribution on the copolymers glass transition temperature, has been used to explain the Tg behavior. The Tg12 has been calculated by the application of Johnston=s equation, given a value sensibly lower than the corresponding homopolymers Tg. The thermal stability of copolymers depends on the composition of the copolymer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070013
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  • 66
    Digitale Medien
    Digitale Medien
    Phase transition of thermosensitive amphiphilic cellulose esters bearing olig(oxyethylene)s (2000)
    Springer
    Polymer bulletin 45 (2000), S. 381-388 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A series of cellulose esters bearing olig(oxyethylene)s with different degree of substitution (DS) and different length of the oxyethylene chain were synthesized by a homogeneous reaction of cellulose with corresponding monofunctional acid chloride in a 10% LiCl-dimethyl acetoamide (DMAc) solution. The effect of total DS value on the solubility of the derivatives in aqueous solution was investigated. It was found that the lower limit DS value for both water-soluble and amphiphilic derivatives decreases with increasing length of oxyethylene chains. The amphiphilic derivatives, which are soluble in both water and chloroform, precipitate out of aqueous solution on heating without gel forming, such a phase transition behavior was studied in terms of DS value, length of oxyethylene and concentration. The precipitation temperature (Tp) of the amphiphilic derivatives is range from 54°C to 96°C. It decreases with increasing the total DS value, and increases with an increase in the length of oxyethylene chains. The Tp value of the derivatives was found to be almost independent in the concentration range of 1–15 wt %, however the Tp value increases sharply with decreasing polymer concentration when the concentration is lower than 1 wt%.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070011
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  • 67
    Digitale Medien
    Digitale Medien
    Effect of heat treatment on the thermal and mechanical properties of polyhydroxyamic acid presursor films (2000)
    Springer
    Polymer bulletin 45 (2000), S. 405-410 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Polyhydroxyamic acid (PHAA) with an inherent viscosity of 0.45 dL/g was prepared from 3, 3'-dihydroxybenzidine and pyromellitic dianhydride. The mechanical and thermal properties of PHAA films and powders before and after annealing were investigated on the basis of their potential use as fire-safe polymers. Cyclization of PHAA to the corresponding hydroxy-containing polyimide is an endothermic reaction. During annealing of PHAA, water was released at 180 °C and carbon dioxide at over 400 °C. The weight residue of PHAA at 900 °C was about 38 %. After annealing at 500 °C, this value increased to 75 %. After annealing at 450 °C, the ultimate stress and initial modulus of the PHAA precursor films increased from 133.8 MPa and 5.86 GPa to 306.2 MPa and 11.0 GPa, respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070014
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  • 68
    Digitale Medien
    Digitale Medien
    Solvent effect on the lower critical solution temperature of biodegradable thermosensitive poly(organophosphazenes) (2000)
    Springer
    Polymer bulletin 45 (2000), S. 389-396 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The solvent effect on the lower critical solution temperature (LCST) of poly(organophosphazenes) with methoxy-poly(ethylene glycol) (MPEG) and amino acid esters as side groups was examined in terms of the structure of polyphosphazenes in aqueous solutions containing one of the organic solvents selected from monoalcohols, ethylene glycol derivatives, alkylamines, and other common solvents. When such a solvent was added to the aqueous solutions of the polymers, their LCST was found to be mainly dependent on the hydrophobic and hydrophilic properties of the solvents. Most of the alcohols and amines with shorter alkyl chains increased the LCST of the polymers but those with longer chains decreased the LCST. Trifluoroethanol (TFE) showed a strong LCST decreasing effect in spite of its short chain, which seems to be due to its strong hydrophobicity. Temperature-induced molecular weight fractionation of the polymer bearing MPEG350 (M w= 350) and L-aspartic acid ethyl ester as a side group was carried out by using the LCST decreasing effect of TFE, and the fractionated samples were characterized by gel permeation chromatography (GPC) and 1H- and 31P NMR spectroscopies. Thus it has been shown that a polymer may be fractionated to the higher and lower molecular weight fractions with smaller polydispersity indices (PDI): the polymer with the weight-average molecular weight (M w) of 73,500 with PDI of 5.56 was fractionated to those of 106,000 with PDI of 4.37 and 11,000 with PDI of 1.86.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070012
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  • 69
    Digitale Medien
    Digitale Medien
    Concentration effects during the formation of poly (acrylic acid)-metal complexes in aqueous solutions (2000)
    Springer
    Polymer bulletin 45 (2000), S. 411-418 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The formation of metal complexes between poly (acrylic acid) and divalent, trivalent and tetravalent metal ions was studied. For divalent metal ions, the formation constants determined according to the method of Gregor et al. strongly decrease with increasing ligand concentration in the range 25–280 mM but are nearly insensitive to the ligand to metal concentration ratio. The metal ions were divided in four groups depending on their effect on the pH decrease of the solution. These groups differ from one another by i) the speed of water exchange or ii) by the speed of ligand exchange in the coordination sphere of the metal. The increase of the ligand concentration or of the ligand to metal ratio always led to an increase of the exchange speed of both water and carboxyl groups.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070015
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  • 70
    Digitale Medien
    Digitale Medien
    Poly(N-vinylpyrrolidone) as metal ion liquid-liquid extractant (2000)
    Springer
    Polymer bulletin 45 (2000), S. 425-429 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: SUMMARY Poly(N-vinylpyrrolidone) (PVP) was investigated as a novel extracting agent. The metal ion extraction properties for Cu(II), Co(II), Ni(II), Cd(II), Zn(II), Pb(II), Hg(II), Cr(III) and Fe(III) were investigated using the liquid-liquid solvent extraction technique (bath method). The metal ion interactions with the polymer were determined as a function of the pH as well as the kinetic characteristic and stripping. For copper ions pH 4 was the optimum extracting pH value, and the 2M hydrochloride acid was better than nitric acid as a stripping agent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070017
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  • 71
    Digitale Medien
    Digitale Medien
    Gaseous products formed by γ-irradiation of bisphenol-A polycarbonate (2000)
    Springer
    Polymer bulletin 45 (2000), S. 419-424 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Bisphenol-A polycarbonate (PC) was γ-irradiated under vacuum at doses from 125 to 1000 kGy. Gases formed were analyzed by gas chromatography - mass spectrometry, and their radiation-chemical yields (G) were calculated. The total G value of gases was equal to 1.00 molec/100 eV, and main products of PC radiolysis were carbon monoxide and hydrogen, their G = 0.87 and 0.08, respectively. Traces of methane, carbon dioxide, acetaldehyde and acetone were detected at doses above 300 kGy. It has been found that acetaldehyde and acetone were produced practically by radiolysis of carbon monoxide - hydrogen mixture evolved from the irradiated PC. Mechanism of gaseous products formation by the PC irradiation has been discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070016
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  • 72
    Digitale Medien
    Digitale Medien
    Water sorption in polymer network films synthesised from PEO oligomers containing acrylic and vinyl ether functionalities (2000)
    Springer
    Polymer bulletin 45 (2000), S. 431-438 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Poly(ethylene oxide) oligomers, with end groups that have either acrylic or vinyl ether functionalities, were photopolymerised by UV radiation to create polymer networks in the form of thin films. Moisture sorption of the polymers, determined by microgravimetric analysis, was correlated to the oligomer structure, i.e. to the PEO chain length and to the type of unsaturation. The data can be described with a Fickian diffusion model using diffusion coefficients of water in the polymer networks on the order of 1 × 10−12 m2/s. The total amount of water sorption at equilibrium saturation increases with an increasing number of EO units in the oligomer used to synthesise the network. The number of absorbed water molecules associated with each EO unit increases with the number of these units in the oligomer until it reaches two water molecules per EO unit, for acrylated-PEO oligomers (PEGDA) having at least 30 EO units. The type of interactions between the polymer network and water were evaluated by means of thermal analysis performed on the hydrated films. It was found that all water is present as bound rather than mobile water.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070018
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  • 73
    Digitale Medien
    Digitale Medien
    Crystallization of polydimethylsiloxane end-linked networks (2000)
    Springer
    Polymer bulletin 45 (2000), S. 439-445 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary End-linked polydimethylsiloxane networks were synthesized, and used to quantify the reduction due to crosslinking of both the extent and thermodynamic stability of the crystalline phase. Networks of varying crosslink density were isothermally crystallized at various temperatures. The consequent melting points were found to be a linear function of the crystallization temperature, enabling equilibrium melting temperatures to be determined by extrapolation. From the dependence of the equilibrium melting point on crosslink density, it was determined that a network junction precludes roughly 8 adjoining chain units from incorporating into the crystal phase. This result is consistent with the measured degree of crystallinity suppression in the networks.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070019
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  • 74
    Digitale Medien
    Digitale Medien
    Preparation of CaCO3/polymer composite films via interaction of anionic starburst dendrimer with poly(ethylenimine) (2000)
    Springer
    Polymer bulletin 45 (2000), S. 447-450 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The CaCO3/poly(ethylenimine) composite film was obtained in the presence of anionic poly(amidoamine) (PAMAM) dendrimer (G=3.5), whereas the formation of composite film was not observed without PAMAM dendrimer or with PAMAM dendrimer (G=1.5) judging from the results of scanning electron micrographs (SEM). The crystal phase of the CaCO3 film formed was found to be calcite by FT-IR and XRD analysis. The adsorption of PAMAM dendrimer on poly(ethylenimine) film might cause local high concentration of calcium ion and induce a formation of the CaCO3 film.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890070020
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  • 75
    Digitale Medien
    Digitale Medien
    On the role of catalyst components in the living metathesis polymerization of substituted acetylenes by MoOCl4-based systems (2000)
    Springer
    Polymer bulletin 44 (2000), S. 129-136 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The role of components in MoOCl4-based living polymerization catalysts was studied. The MALDI TOF MS spectra of the poly(o-[(trifluoromethyl)phenyl]acetylene)s prepared with n-Bu4Sn and Et3Al as cocatalysts suggested a difference of 28(C2H4) in polymer molecular weight. This indicates that the formed polymer possesses an alkyl group of cocatalyst in the initiating chain end, which implies the transalkylation between MoOCl4 and a cocatalyst and the subsequent formation of a Mo carbene. Sterically uncrowded aliphatic alcohols were useful as the third catalyst components. Addition of EtOH to the catalyst system led to the increase of activation enthalpy and the change of activation entropy from a negative to positive value in the propagation reaction, which suggests that EtOH coordinates to the propagating end competitively with the monomer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050583
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  • 76
    Digitale Medien
    Digitale Medien
    Functionalization of coumarone-indene resins I. Acetoacetylation (2000)
    Springer
    Polymer bulletin 44 (2000), S. 151-158 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A low molecular weight coumarone (or 2,3-benzofuran)-indene resin was converted to a β-ketoester functional material by Friedel-Crafts acylation with acetyl chloride, reduction to a secondary alcohol and reaction with t-butyl acetoacetate. Each reaction was essentially quantitative as shown by spectroscopy and elemental analysis. The final product proved to be crosslinkable at ambient or elevated temperature by the addition of multifunctional amines.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050586
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  • 77
    Digitale Medien
    Digitale Medien
    Synthesis of polymers having arylene-vinylene units by palladium-catalyzed hydroarylation polymerization of diethynylbenzene derivatives (2000)
    Springer
    Polymer bulletin 44 (2000), S. 137-142 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Arylene-vinylene-containing polymers with fully aromatic backbone structures were prepared by the palladium-catalyzed hydroarylation polymerization of diethynylbenzene derivatives with diiodobenzene and alkylmalonate anions as a hydride source. For instance, the polymerization of 1,4-bis(4'-dodecyloxy)phenylethynylenebenzene, diiodobenzene, and sodium diethyl benzylmalonate was carried out at 80°C for 2 days in 1,4-dioxane in the presence of Pd(OAc)2 / tri-o-tolylphosphine (7 equiv. to Pd) to produce a polymer (M n= 6,390, M w/M n= 1.53) in high yield (86 %). Using various diethynylbenzene derivatives, polymers having arylene-vinylene units were also obtained in high yields.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050584
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  • 78
    Digitale Medien
    Digitale Medien
    Perfectly alternating poly(arylene ether ketone sulfone)'s (2000)
    Springer
    Polymer bulletin 44 (2000), S. 143-150 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary In this study, the synthesis of perfectly alternating poly(arylene ether ketone sulfone)'s (PAEKS) via their soluble poly(arylene ether ketimine sulfone) (PAEKetS) intermediates was described. In the first stage of this procedure a new bishalide monomer, 1,1'-bis(4-fluoro(n-benzohydroxylidene aniline)) sulfone (FBHAS) was synthesized. In the second stage, the polymerization of this monomer with various aromatic bisphenols to form the amorphous PAEKetS's and then the hydrolysis of the ketimine groups on the PAEKetS's backbones to ketones in mild acidic conditions in order to obtain perfectly alternating PAEKS's was conducted.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050585
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  • 79
    Digitale Medien
    Digitale Medien
    Synthesis and behaviour of two copolymers of poly[acrylamide-co-(N-(hydroxymethyl)acrylamide)] in ultrafiltration experiments (2000)
    Springer
    Polymer bulletin 44 (2000), S. 159-165 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: SUMMARY The synthesis of two copolymers of poly[acrylamide-co-(N-(hydroxymethyl)acrylamide)] is described. Polymer analogous reactions have been used as well as direct radical polymerization. The two copolymers have been fractionated and ultrafiltered in the presence of Cu2+, Cd2+, Co2+, Ni2+, Pb2+, Zn2+, and an excess of Na+. It has been found that Na+ ions do not interact with the copolymers. The effect of the different composition of the copolymers is noted in the study of Cu2+ and Pb2+, but there is no difference in the retention profiles obtained for the rest of the metal ions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050587
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  • 80
    Digitale Medien
    Digitale Medien
    Nickel (salen) / methylaluminoxane catalyzed polymerization of norbornene (2000)
    Springer
    Polymer bulletin 44 (2000), S. 167-172 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Nickel (salen) in conjunction with methylaluminoxane (MAO) catalyzes the polymerization of norbornene to poly (2,3-bicyclo [2.2.1] hept-2-ene) [poly (norbornene)]. Methylaluminoxane (MAO) was used as cocatalyst as such (MAO-I) and after distilling off free trimethylaluminium (MAO-II). The catalyst system was very active in chlorobenzene at room temperature. It was also found that MAO-II gave higher activity as compared to MAO-I. The samples of polynorbornene were soluble in 1,2,4-trichlorobenzene. The poly (norbomene)s were characterized by intrinsic viscosity and thermal properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050588
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  • 81
    Digitale Medien
    Digitale Medien
    Porosity analysis of some poly(styrene/divinylbenzene)beads by nitrogen sorption and mercury intrusion porosimetry (2000)
    Springer
    Polymer bulletin 44 (2000), S. 179-189 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: SUMMARY: Highly crosslinked poly(styrene/DVB) beads have been synthesised by suspension polymerisation using different porogens and porogens mixtures. The porosity of the resulting resins was analysed by the nitrogen and mercury intrusion porosimetry techniques.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050590
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  • 82
    Digitale Medien
    Digitale Medien
    Properties of molecular composite film of poly(4,4'-diamino-2'-carbamoylbenzanilide terephthalamide)(p-PDCBTA) and poly(4,4'-diamino-2'-chlorobenzanilide terephthalamide) (P-LCI) (2000)
    Springer
    Polymer bulletin 43 (2000), S. 505-510 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary A new thermally stable, high strength and high modulus aromatic polyamide film was obtained via the formation of the molecular composite of p-PDCBTA and P-LCl. The two polymers exhibited good miscibility identified with the measurement of dynamic mechanical property and FTIR spectra. By the combination of drawing by 40% and subsequent heat treatment, the tensile property of the composite film could be achieved to the strength of 450 MPa and the modulus of 24 GPa, which were sustainable upto 400 °C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050008
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  • 83
    Digitale Medien
    Digitale Medien
    Amphiphilic networks. XIV (2000)
    Springer
    Polymer bulletin 43 (2000), S. 511-518 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The synthesis and characterization of novel amphiphilic networks based on dimethylacrylamide and crosslinked by methacrylate telechelic three-arm star polyisobutylene (Ø(PIB-MA)3) are reported. The networks are characterized by two M c's and possess “homogeneous” and “heterogeneous” crosslinks. The networks swell both in water and n-heptane which indicates a cocontinuous hydrophobic-hydrophilic microarchitecture. Water-swollen networks exhibit higher tensile strengths and elongations, than those made previously with linear MA-PIB-MA's of similar overall compositions (i.e., ∼1.0 versus ∼0.5 Mpa, and ∼300% versus ∼200%, respectively). The enhanced mechanical properties of the new networks are being exploited in biomedical applications.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050009
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  • 84
    Digitale Medien
    Digitale Medien
    Rheological monitoring of curing reaction of an epoxy system: effect of heating rate (2000)
    Springer
    Polymer bulletin 43 (2000), S. 519-526 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary In this work, we present a rheological study of the non-isothermal curing reaction of an epoxy resin, diglycidyl ether of bisphenol A, with aliphatic amines of different functionalities. The reaction was carried out under a linear temperature program and the epoxy-amine mixtures were prepared at different epoxy groups to amine-hydrogen ratios. The effect of vitrification on the curing reaction is analyzed as a function of the heating rate. At low heating rates, the viscous modulus, G″, presents two peaks. The first peak is due to the vitrification-devitrification phenomenon that takes place during cure. At the second peak, the sample is completely cured and the decrement is G″ is only due to the temperature increment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050010
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  • 85
    Digitale Medien
    Digitale Medien
    New AB or ABA type block copolymers: atom transfer radical polymerization (ATRP) of methyl methacrylate using iodine-terminated PVDFs as (macro)initiators (2000)
    Springer
    Polymer bulletin 44 (2000), S. 1-8 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary PMMA homopolymer with CF3(CF2)2CF2- end group was prepared by the ATRP of MMA using CF3(CF2)2CF2-I as an initiator and copper(I) salts/bipy catalysts. This indicated the production of perfluorobutyl radicals by ATRP mechanism and successful polymerization by them. Di- and triblock copolymers were also prepared by the ATRP of MMA using iodine-terminated PVDF as (macro)initiators. The kinetic plots (ln[M]o/[M] vs. time) showed nearly first-order with respect to monomer concentration and the Mn,NMR of block copolymers increased linearly with conversion. However, iodine-terminated PVDF showed low initiator efficiency because propagating rate was much faster than initiating rate
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050566
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  • 86
    Digitale Medien
    Digitale Medien
    Photochromic organic-inorganic polymer hybrids from spiropyran-modified poly(N,N-dimethylacrylamide) (2000)
    Springer
    Polymer bulletin 44 (2000), S. 9-15 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Photochromic organic-inorganic polymer hybrids were prepared by the sol-gel reaction of tetramethoxysilane (TMOS) in the presence of spiropyran-modified poly(N,N-dimethylacrylamide) 3. The obtained polymer hybrids were characterized by thermogravimetric analysis (TGA) and FT-IR, and photochromic behavior was followed by electronic absorption spectroscopy. Upon an irradiation of ultraviolet light, an absorption around 557 nm appeared in the visible region and the color of the hybrid turned to be violet. The effect of silica gel on the isomerization behavior seemed to be relatively small.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050567
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  • 87
    Digitale Medien
    Digitale Medien
    Preparation and oil-absorptivity of crosslinked polymers containing stearylmethacrylate, 4-t-butylstyrene, and divinylbenzene (2000)
    Springer
    Polymer bulletin 44 (2000), S. 17-24 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The crosslinked polymers, poly(stearylmethacrylate-co-divinylbenzene) [CP(SMA-co-DVB)] and poly(t-butylstyrene-co-divinylbenzene) [CP(tBS-co-DVB)], and CP(SMA-co-DVB)/PtBS IPNs, were prepared by the polymerization of corresponding monomer pairs in the presence of BPO. The structures and thermal properties of CP(SMA-co-DVB), CP(tBS-co-DVB), and the IPN were determined by FT-IR, DSC, and TGA. The oil-absorptivities of CP(SMA-co-DVB) and CP(SMA-co-DVB)/PtBS IPN decreased with increasing concentrations of DVB and tBS, respectively. The highest oil-absorptivities of CP(SMA-co-DVB) and the IPN(PtBS: 25%) were 615 % and 330 %, respectively. The toluene absorptivity of the synthesized polymers decreased in following order: CP(tBS-co-DVB) 〉 CP(SMA-co-DVB) 〉 IPN(PtBS: 25 %) 〉 IPN(PtBS: 50 %) 〉 IPN(PtBS: 75 %) at immersion above 60 min.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050568
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  • 88
    Digitale Medien
    Digitale Medien
    Controlled polymerization of DL-lactide using a Schiff's base al-alkoxide initiator derived from 2-hydroxyacetophenone (2000)
    Springer
    Polymer bulletin 44 (2000), S. 31-38 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary The kinetics of DL-lactide polymerization was studied in CH2Cl2 at 25°C and in toluene at 70°C with HAPENAlOMe, a new Schiff's base complex derived from 2-hydroxyacetophenone and ethylenediamine. A higher polymerization rate is observed with this initiator as compared to other previously reported Al-alkoxides complexes. The polymerization with HAPENAlOMe is also shown to be a living process in both solvents. Moreover, the polymerization proceeds to quite high conversion without significant occurrence of transesterification reactions as confirmed from 13C NMR and SEC analysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050570
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  • 89
    Digitale Medien
    Digitale Medien
    Bromine as an initiator for the oligomerization of vinylformamide (VFA) (2000)
    Springer
    Polymer bulletin 44 (2000), S. 39-46 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Summary Bromine was found to be an effective initiator for the cationically induced oligomerization of vinylformamide (VFA). Oligomeric products with molecular weights between 200 and 1500 g/mol were obtained. The structures of the oligo(vinylformamides) (OVFA) were investigated by means of NMR spectroscopy, GPC, and MALDI-TOF-MS. The influence of the reaction temperature on yield, DP, and head group functionality of the obtained OVFA was investigated. When the 1: 1 adduct of bromine with VFA was used as initiator at 253 K, also oligomeric products are obtained.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050571
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  • 90
    Digitale Medien
    Digitale Medien
    Sol-gel synthesis of Ru(II) complex of 3-4,5-dihydroimidazol-1-yl-propyltriethoxysilane aerogels and xerogels (2000)
    Springer
    Polymer bulletin 44 (2000), S. 47-53 
    Details
    ISSN: 1436-2449
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: ABSTRACT The preparation and the measurement of some properties of Ruthenium (II) coordinated 3-4,5-dihyroimidazol-1-yl-propyltriethoxysilane have been achieved. The organosilicon precursor chosen for this study was N-aminoethyl-3-aminopropyltriethoxysilane converted to 3-4,5-dihydroimidazol-1-yl-propyltriethoxysilane that was then coordinated with ruthenium (II). FT-IR spectroscopy, DTA and TGA analysis were used to characterize the bond formation during gelation, aging and drying of gels. The prepared aerogels are low-density 0.19–0.30 g/cm3 amorphous materials with surface areas of 405 to 530 m2/g. The resulting aerogel catalysts exhibited unique structural and chemical properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002890050572
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  • 91
    Digitale Medien
    Digitale Medien
    Determination of the diffusion coefficient of water into atelocollagen type I thin films by attenuated total reflection Fourier transform infrared spectroscopy (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1014-1016 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Atelocollagen type I ; Attenuated total reflection ; Fourier transform infrared spectroscopy ; Diffusion coefficient ; Thin films
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  The diffusion coefficient of water into thin polymer layers of glutar aldehyde cross-linked atelocollagen type I matrix (sample 1, the typical layer thickness was about 0.065 × 10−3 m) at 23 °C was 1.142 × 10−10 m2 s−1. At twice the concentration of the cross-linking agent (sample 2) the diffusion coefficient was 2.795 × 10−10 m2 s−1. This increase was attributed to the more ordered morphology and the creation of ordered microvoids in the film. A larger surface area is then available for the transport of diffusing molecules, allowing a higher penetration rate of the solvent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000366
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  • 92
    Digitale Medien
    Digitale Medien
    Relationships between ringed spherulitic morphology and miscibility in blends of poly(ɛ-caprolactone) with poly(benzyl methacrylate) versus poly(phenyl methacrylate) (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1032-1042 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Spherulites ; Ring bands Interactions ; Miscibility ; Poly(ɛ-caprolactone)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  Ringed spherulites are an interesting phenomenon that is observed only in very few miscible systems. For the first time, the relationship between the state of chain intermixing and the ring-band pattern was demonstrated. Two previously demonstrated miscible blend systems, poly(ɛ-caprolactone) (PCL) with poly(benzyl methacrylate) (PBzMA) and PCL with poly(phenyl methacrylate) (PPhMA), were studied in order to understand the mechanism of ring-band formation in the spherulites and the relationships between the ring-band pattern and the state of miscibility. In both miscible PCL/PBzMA and PCL/PPhMA systems, extinction rings were observed within the PCL spherulites. In the PCL/PBzMA blend, the extinction rings are not as distinct (owing to distortion) as those in the PCL/PPhMA blend system. Analysis was performed and discussions were made to reveal relationships between miscibility, interaction strength, and the pattern of the ring bands in the PCL spherulites in polymeric mixtures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000355
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  • 93
    Digitale Medien
    Digitale Medien
    Investigation of molecular order and phase transitions of smectic poly(ester imide)s by means of small-angle X-ray scattering (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1061-1069 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Smectic ; Poly(ester imide)s ; Small-angle X-ray scattering ; Lamellar
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The molecular order and phase transitions of two smectic poly(ester imide)s based on aminobenzoic acid trimellitimide (PEI 1) or aminocinnamic acid trimellitimide (PEI 2) and α,ω-dihydroxydodecane were investigated by X-ray scattering. During cooling, the polymers pass through monotropic smectic liquid-crystalline (LC) phases (SA, SC), which transform into higher-ordered smectic-crystalline phases (SE, SH). The smectic layer structure of about 3 nm gives rise to a sharp reflection at 2θ ≅ 3°. Peak shape analysis and analysis of the interface distribution function revealed long-range longitudinal correlation among the mesogens in the LC phase but short-range lateral correlation. The development of a broad reflection in the small-angle X-ray scattering (SAXS, 2θ 〈 1°) indicates the formation of a lamellar two-phase system. The long-period changes reversibly between 10 and 30 nm with increasing temperature. The crystalline lamellae comprise a number of smectic-crystalline layers with packed mesogens, while the noncrystalline interlamellar regions keep their smectic-LC order. In the metastable SB phase, formed during annealing of quenched PEI 1, the diffuse SAXS indicates a random distribution of small, probably fringed, crystals with hexagonal-packed mesogens. In the lamellar SE and SH phases, tie molecules play an important role, but chain folding cannot be excluded.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000370
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  • 94
    Digitale Medien
    Digitale Medien
    Surfactant effect on the lower critical solution temperature of poly(organophosphazenes) with methoxy-poly(ethylene glycol) and amino acid esters as side groups (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1097-1102 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Polyphosphazene ; Thermosensitivity ; Lower critical solution temperature ; Surfactant effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  The surfactant effect on the lower critical solution temperature (LCST) of thermosensitive poly(organophosphazenes) with methoxy-poly(ethylene glycol) and amino acid esters as side groups was examined in terms of molecular interactions between the polyphosphazenes and surfactants including various anionic, cationic, and nonionic surfactants in aqueous solution. Most of the anionic and cationic surfactants increased the LCST of the polymers: the LCST increased more sharply with increasing length and hydrophobicity of the hydrophobic part of the surfactant molecule. The ΔLCSTs (T 0.03M − T 0M), the change in the LCST by addition of 0 and 0.03 M sodium dodecyl sulfate (SDS), were found to be 7.0 and 14.5 °C for the polymers bearing ethyl esters of glycine and aspartic acid, respectively. The LCST increase of poly(organophosphazene) having a more hydrophobic aspartic acid ethyl ester was 2 times larger compared with that of the polymer having glycine ethyl ester as a side group. The binding behavior of SDS to the polymer bearing glycine ethyl ester as a hydrophobic group was explained from the results of titration of the polymer solutions containing SDS with tetrapropylammonium bromide. Graphic models for the molecular interactions of polymer/surfactant and polymer/surfactant/salt in aqueous solutions were proposed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000368
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  • 95
    Digitale Medien
    Digitale Medien
    Investigation of the association in water of sodium dodecyl sulfate with a positively charged copolymer based on N -isopropylacrylamide (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1109-1113 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Poly(N-isopropylacrylamide) ; Sodium dodecyl sulfate ; Lower critical solution temperature ; Coil-to-globule transition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The interactions of sodium dodecyl sulfate with a positively charged copolymer based on N-isopropylacrylamide (NIPAM) have been investigated in aqueous solution by turbidimetric and viscometric measurements. The copolymer contains mainly NIPAM and only 5 mol % of the charged comonomer [3-(methacryloylamino)propyl]-dimethyloctylammonium bromide. The polymer–surfactant complex is insoluble for mixture compositions near to the charge stoichiometry, while it exhibits lower critical solution temperature behavior for mixtures with an excess of polymer or surfactant. In the case of surfactant excess, the transition from an expanded coil to a globular state upon heating has been observed by viscometry.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000377
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  • 96
    Digitale Medien
    Digitale Medien
    Polymerisation in supported bilayers (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1114-1118 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Organically modified clay minerals ; Polymerisation ; Supported bilayers ; Dioctadecyldimethylammonium bromide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The intercalation of the twin-tailed amphiphilic dioctadecyldimethylammonium (DODA) ions in smectite clay minerals provides a well-defined supported bilayer system. Polymerisation of styrene in these robust model bilayers allows one to focus on the effect of the constrained medium on the polymerisation process and the polymer. Small-angle X-ray scattering analysis and differential scanning calorimetry data indicated that the polymerisation of styrene in DODA–montmorillonite leads to phase separation between polystyrene and the surfactant matrix.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000378
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  • 97
    Digitale Medien
    Digitale Medien
    Chemical deposition and characterization of thin polypyrrole films on glass plates: role of organosilane treatment (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1139-1154 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Polypyrrole ; Glass ; Organosilanes ; Wettability ; Hydrophobic interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  Thin chloride-doped polypyrrole films (PPyCl) were deposited chemically onto untreated and silane-treated planar glass plates from aqueous solutions. The organosilanes used to treat the glass substrates were methyltriethoxysilane (Cl), propyltrimethoxysilane (C3), octyltrimethoxysilane (C8) and aminopropyltriethoxysilane (APS). The decreasing order of hydrophobic character of silane-treated glass slides, as measured by water contact angle measurements, was glass–APS ≅ glass–C8 〉 glass–C3 〉 glass–C1 〉 glass. X-ray photoelectron spectroscopy was used to determine the surface chemical composition of the glass plates before and following coating with the silane coupling agents and/or the PPy thin layer, respectively. The attenuation in intensity of the glass Na1 s peak enabled the average thickness of the various organosilane overlayers to be estimated. Atomic force microscopy showed that the morphology of the organosilane overlayers was islandlike. The domains have a structure which depends upon the nature of the organosilane in question. Scanning electron microscope images showed that the morphology of the PPyCl thin films was homogeneous when coated onto glass–APS and glass–C8, but wrinkled at the surface of glass, glass–C1 and glass–C3 plates. Qualitative peel tests using 3M adhesive tape showed very good adhesion of PPyCl to the glass–APS substrate, whereas adhesion was fairly poor in the case of glass–PPy and PPy–alkylsilane–glass interfaces. The results of this multitechnique study suggest that hydrophobic interactions are important to obtain homogeneous and continuous thin PPy films, but Lewis acid–base interactions are the driving forces for strong and durable PPy–glass adhesion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000372
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  • 98
    Digitale Medien
    Digitale Medien
    Aggregation behaviour of hydrophobically modified poly(allylammonium) chloride (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 1052-1060 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Cationic amphiphilic polymers ; Aggregation ; Pyrene fluorescence spectroscopy ; Hydrophobic microdomains
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract  The behaviour of hydrophobically modified poly(allylammonium) chloride having octyl, decyl, dodecyl and hexadecyl side chains has been studied in aqueous solution using fluorescence emission techniques. Micropolarity studies using the I 1/I 3 ratio of the vibronic bands of pyrene show that the formation of hydrophobic microdomains depends on both the length of the side chain and the polymer concentration. The I 1/I 3 ratio of the polymers with low hydrophobe content (less than 5% mol) changes substantially when reaching a certain concentration. These changes are assigned to aggregation originating from interchain interactions. This behaviour is also confirmed by the behaviour of the monomer/excimer emission intensities of pyrenedodecanoic acid used as a probe. For polymers having dodecyl side chains and hydrophobe contents higher than 10%, aggregates are formed independently of the polymer concentration. Anisotropy measurements show that microdomains resulting from the inter- and/or intramolecular interactions are similar to those observed for cationic surfactants. Viscosity measurements show that the coil dimensions are substantially decreased for the polymers having high hydrophobe contents, indicating intramolecular associations.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960000367
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  • 99
    Digitale Medien
    Digitale Medien
    Complexation in the heptanoic acid–heptylamine system (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 8-14 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Alkanoic acid ; Alkylamine ; Catanionic surfactant ; Ternary phase diagram
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The complexation between heptylamine and heptanoic acid has been elucidated at 298.15 K using spectroscopic methods and also by measuring macroscopic quantities such as viscosity, conductivity and surface tension. Fourier transform IR and 13C NMR measurements point towards the existence of a compound consisting of one amine molecule and one acid molecule in an equimolecular mixing ratio. These suggestions are supported by viscosity and surface tension measurements. This compound is further able to interact with excess acid, but similar behaviour is not observed with excess amine. The equimolecular compound behaves like a catanionic surfactant; this is seen in the phase diagram for the heptylamine–heptanoic acid–water system at 298.15 K, where the dominating phase is the lamellar liquid-crystalline phase. This phase is in equilibrium with almost pure water. At low water content a solution phase extending from the binary heptylamine–heptanoic acid axis and covering all mixing ratios between the amine and the acid is also present.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960050002
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  • 100
    Digitale Medien
    Digitale Medien
    Interfacial and micellar properties of some anionic/cationic binary surfactant systems. 1. Surface properties and prediction of surface tension (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 22-29 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Surface tension ; Anionic/cationic surfactants ; Mixed monolayer composition ; βs interaction parameter ; Gas–liquid adsorption free energy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The surface tension equations of binary surfactant mixtures are established by combining the Szyszkowski equation for pure surfactant solutions and extended nonideal theory for mixed adsorption. They are then successfully applied to two relatively long-chain anionic/cationic binary surfactant systems: triethanolammonium dodecylpoly(oxyethylene)sulfate, as an anionic species (containing about 2 ethylene oxide units), mixed with dodecyltrimethylammonium bromide or hexadecyltrimethylammonium bromide. The composition of the mixed monolayer is mixing-ratio dependent and is slightly asymmetric: for overall equimolar mixtures, the larger mole fraction in the mixed monolayer is that of the more surface-active ion. The strong synergetic effects observed in the surface tension reduction efficiency are reflected by large negative βs parameters, according to regular solution theory. They can be interpreted by the more negative adsorption free energy of each surfactant and the smaller area occupied by surfactant hydrocarbon chains in the mixed monolayer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960050004
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