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  • Articles  (125,436)
  • Springer  (125,436)
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  • Articles  (125,436)
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  • 1
    Electronic Resource
    Electronic Resource
    A study on the adsorption of some cationic dyes onto acrylamide/itaconic acid hydrogels (1996)
    Springer
    Polymer bulletin 36 (1996), S. 745-752 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Acrylamide/itaconic acid (AAm/IA) hydrogels prepared by irradiating with γ radiation were used in experiments on the adsorption of some cationic dyes such as basic red 9 (BR 9), basic green 4 (BG 4), cresyl violet (CV), and basic blue 20 (BB 20). Adsorption of the cationic dyes onto AAm/IA hydrogels is studied by batch adsorption technique. In the experiments of the adsorption, Langmiur type adsorption in the Giles classification system was found. Monolayer coverages for AAm/IA hydrogel-dye systems were calculated by using B point method. Adsorption studies indicated that monolayer coverages of AAm/IA hydrogel by these dyes were increased with following order; BB 20〉CV〉BR9〉BG 4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00338639
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  • 2
    Electronic Resource
    Electronic Resource
    Polymerization of styrene by diphenylzinc-additive systems (1996)
    Springer
    Polymer bulletin 37 (1996), S. 13-19 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Styrene was polymerized using combined systems of diphenylzinc, Ph2Zn, and metallocene compounds activated by methylaluminoxane, MAO. From the various metallocenes employed bis (indenyl) zirconium dichloride, Ind2ZrCl2, [isopropyl (cyclopentadienyl) (1-fluorenyl)] zirconiumdichloride, i-Pr (Flu) (Cp) ZrCl2, and bis (cyclopentadienyl) titanium dichloride, Cp2TiCl2, produced the larger amounts of polymer. Ph2Zn-Cp2TiCl2-MAO system gave polystyrene, PSt, whose DSC analysis indicated a major endotherm peak at 256°C. A butanone insoluble fraction of the polymer was separated from the crude PSt. The proportion of insoluble polymer depends on the metallocene employed and on the conversion to polymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313813
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  • 3
    Electronic Resource
    Electronic Resource
    Isotactic polymerization of propylene with zirconocene catalysts in the presence of a lewis base (1996)
    Springer
    Polymer bulletin 37 (1996), S. 29-33 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Polymerization of propylene was carried out at 0°C in the presence of methyl methacrylate(MMA) or ethyl benzoate(EB) using rac-Et(Ind)2ZrMe2 or rac-Me2Si(Ind)2ZrMe2/Ph3CB(C6F5)4 as catalyst, which resulted in highly isotactic poly(propylene) with [mmmm]〉98%, Tm=160–161°C and very few 1,3- or 2,1 regioirregular units. With the use of an achiral zirconocene Cp2ZrMe2, a polymer with Tm=139°C was resulted as well. Base on these experimental fact that the zirconocene can form a C1-symmetrical complex with a Lewis base.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313815
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  • 4
    Electronic Resource
    Electronic Resource
    Highly active rare earth catalysts for the solution polymerization of ε-caprolactone (1996)
    Springer
    Polymer bulletin 37 (1996), S. 21-28 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary By using γ-butyrolactone (γ-BL) as the reaction media, highly active catalysts--light rare earth chloride-epoxidy-γ--BL-for the solution polymerization of ε-caprolactone, have been obtained for the first time. With these catalyst, PCL with molecular weight as his as 40x104(Mv) can be prepared at 60°C for 1.5 hr. The amount of epoxide in catalyst solution, catalyst aging temperature and time affect the catalyst activity significantly. The mechanism study shows that in γ-BL, the weakening of Ln-Cl bonds by the donation of coordinated γ-BL with Ln3+ and the homogenous effect promote the reaction between light rare earth chloride and epoxide. The produced rare earth alkoxide initiates CL polymerization via a ‘coordination-insertion’ mechanism with Acyl-oxygen bond cleavage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313814
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  • 5
    Electronic Resource
    Electronic Resource
    Surface modification of ethylene-vinyl alcohol (EVOH) copolymer films by the attachment of triethoxysilane functionality (1996)
    Springer
    Polymer bulletin 37 (1996), S. 51-57 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Triethoxysilane groups were covalently attached onto the surface of ethylene-vinyl alcohol (EVOH) copolymer film via a urethane linkage through reaction between the hydroxyl groups in EVOH and 3-isocyanatopropyltriethoxysilane in the presence of dibutyltin dilaurate as catalyst. This reaction was confirmed by ATR-IR and XPS analysis. XPS results also indicated that this reaction was not surface sensitive and the modified layer was at least 40 Å in depth. The modified film samples were further reacted with tetramethoxysilane (TMOS) for partial hydrolysis and condensation and XPS results showed a significant increase in the contents of oxygen and silicone on the surface which confirmed the above reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313818
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  • 6
    Electronic Resource
    Electronic Resource
    An analysis of the 1H- and 13C-NMR spectra of poly(6-vinyl-1,4-benzodioxane) (1996)
    Springer
    Polymer bulletin 37 (1996), S. 59-65 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The title monomer was synthesized from the corresponding aldehyde via a Wittig reaction. The monomer was polymerized using free radical initiation and its high field 1H- and 13C-NMR spectra were recorded. When analyzed in terms of stereochemistry the spectra showed poly(6-vinyl-1,4-benzodioxane) is an atactic polymer when synthesized via free radical initiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313819
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  • 7
    Electronic Resource
    Electronic Resource
    Dual sorption of metal-ions on a crosslinked resin of 2-acrylamidoglycolic acid and 4-vinylpyridine (1996)
    Springer
    Polymer bulletin 37 (1996), S. 191-198 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A resin containing 4-vinylpyridine and 2-acrylamidoglycolic acid was synthesized by radical polymerization with subsequent crosslinking by N,N′-methylene-bis-acrylamide. The resin was characterized by elemental analyses and FT-IR spectroscopy. The ability of this resin as well as both crosslinked homopolymers to bind Cu(II), Fe(II), Fe(III) and U(VI) was studied at different pHs depending on the metal ion. From pH=2 U(VI) was sorbed above 96% from an aqueous solution of 1.0 g/L. A dual sorption mechanism to U(VI) depending on the pH is suggested. The elution of the metal ions from the loaded resins was assayed with H2SO4 and Na2CO3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294121
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of the sulfide group on photopolymerization kinetics of di(meth)acrylates (1996)
    Springer
    Polymer bulletin 37 (1996), S. 199-206 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The photopolymerization of four analogous monomers: 2,2′-thiobisethanol diacrylate and its dimethacrylate plus 2,2′-oxybisethanol diacrylate and its dimethacrylate has been studied by isothermal differential scanning calorimetry (DSC) over a range of incident light intensities. The results obtained prove that the sulfide group accelerates polymerization both in the presence and absence of oxygen and enhances the conversion. The light intensity exponents for each monomer were determined and the mechanism of termination was discussed. The intensity exponents of sulfur-containing monomers are lower than their corresponding oxygen analogues, pointing to a greater participation of the bimolecular termination during their polymerization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294122
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  • 9
    Electronic Resource
    Electronic Resource
    Size distribution of polymers during the photoinitiated free-radical copolymerization of methyl methacrylate and ethylene glycol dimethacrylate (1996)
    Springer
    Polymer bulletin 37 (1996), S. 207-213 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Photoinitiated methyl methacrylate-ethylene glycol dimethacrylate (MMA/EGDM) copolymerization has been investigated in toluene at a monomer concentration of 35 w/v %. Diphenyl-2,4,6-trimethylbenzoylphosphine oxide (DPTPO) was used as a photoinitiator at 0.3 wt% concentration. Monomer conversions and the size distribution of the polymer molecules were measured as a function of the reaction time up to the onset of macrogelation. Compared to the photoinitiators benzoin or benzoin derivatives, gelation process proceeds at much higher rates in the presence of DPTPO. The size distribution curves obtained by size-exclusion chromatography (SEC) change from monomodal to bimodal distributions as the polymerization proceeds. Strongly bimodal SEC curves were obtained in the close vicinity of the gel point. This finding confirms the coagulation type gelation mechanism of compact primary particles. It also indicates that the present gelation theories cannot describe the structure dependent kinetics of free-radical crosslinking copolymerization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294123
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  • 10
    Electronic Resource
    Electronic Resource
    FT-Raman analysis of the effects of γ-radiation on nylon 6–12 filaments (1996)
    Springer
    Polymer bulletin 37 (1996), S. 221-228 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary FT-Raman spectroscopy of commercial amorphous and crystalline nylon 6–12 filaments subjected to various γ-radiation doses are presented. The results show that a difference exists in the interaction of γ-radiation with these polyamides, depending on the crystallinity which can be evaluated by measuring the CH-stretching/CH-bending Raman band intensity ratio as a function of applied γ-dose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294125
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  • 11
    Electronic Resource
    Electronic Resource
    Solid-state NMR study of natural rubber blended with EVA and EVA modified with mercaptoacetic acid (1996)
    Springer
    Polymer bulletin 37 (1996), S. 215-220 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Solid-state 13C NMR spectroscopy involving magic angle spinning (MAS) techniques with and without cross-polarization was employed for interaction studies in natural rubber (NR)/EVA and NR/mercapto-modified EVA (EVASH) blends. From arrayed of variable contact time spectra, the proton T1ϱ values were determined at short contact times to analyze the EVA or EVASH domains and longer contact times to investigate the interactions in the NR domains. Substantial changes have been observed when dicumyl peroxide was employed as curing agent in NR/EVASH and NR/EVA/EVASH blends.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294124
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  • 12
    Electronic Resource
    Electronic Resource
    Thermogravimetric analysis of starch-based biodegradable blends (1996)
    Springer
    Polymer bulletin 37 (1996), S. 229-235 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Thermogravimetric analysis (TGA) has been shown to be a useful technique to determine the content of starch and other components that are usually present in blends of starch with synthetic polymers. However, some of these blends are composed of elements with an important superposition in their temperature degradation range. In these cases interpretation of the TGA results becomes quite difficult and usually important errors are committed in the determination of blend composition. We present here a method to improve the accuracy of the interpretation of TGA data. The analysis was developed to study blends containing starch, an ethylene-vinyl alcohol copolymer, and water plus glycerin as plasticizers. Using this procedure it is possible to predict blend composition with an error less than 3%, even when there is an appreciable superposition between the temperature degradation range of starch and poly(ethylene-co-vinyl alcohol). As the proposed method of analysis is quite general it may be extended to be used with other types of blends that give thermograms with similar characteristics to those described in this paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294126
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  • 13
    Electronic Resource
    Electronic Resource
    Synthesis of polysulfone block copolymers containing polydimethylsiloxane (1996)
    Springer
    Polymer bulletin 37 (1996), S. 329-336 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The synthesis of polysulfone-polydimethylsiloxane (PSU-PDMS)linear block copolymers has been carried out in solution by condensation of chloro-terminated bisphenol A, diphenylsulfone and α, ω-di (hydrogensilyl)-polydimethylsiloxane with Si−C bond. 1H-NMR spectra of the block copolymers allow the estimation of siloxane and polysulfone ratio. The molecular weight of the polysulfone and polysiloxane oligomers and the block copolymers was determined by GPC. Thermogravimetric analysis indicates a thermal stability of block copolymers up to 400°C and allows estimation of the process activation energy. Microphase separation of the block copolymers was observed by differential scanning calorimetry (DSC).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318065
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  • 14
    Electronic Resource
    Electronic Resource
    Compatibilization of PP/PBT and PP/PA6 blends with a new oxazoline-functionalized polypropylene (1996)
    Springer
    Polymer bulletin 37 (1996), S. 353-359 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Aim of this work was to study the effectiveness of a novel oxazoline-functionalized polypropylene as a compatibilizer for PP/PBT and PP/PA6 blends. This polypropylene-based compatibilizer mixes well with the polypropylene and is capable of reacting with the carboxylic and amine end groups of PBT and PA6. Significant improvements in blend toughness were achieved without reduction in strength and stiffness. These effects were related to stabilized morphology of finely dispersed minor phase well attached to the matrix. The enhanced interfacial interactions between the two phases, in particular at high PBT content were evidenced by increased melt viscosity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318068
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  • 15
    Electronic Resource
    Electronic Resource
    Miscibility of polyamide-6,6 with aromatic polyamides (1996)
    Springer
    Polymer bulletin 37 (1996), S. 361-367 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The polyamides with aromatic rings in the main chain were synthesized by the solution polymerization of 4,4′-diphenylmethane diisocyanate and aliphatic dicarboxylic acid in the presence of catalyst. The thermal properties and the miscibility behaviours with polyamide-6,6 of these aromatic polyamides were studied. The aromatic polyamides synthesized with one kind of dicarboxylic acid had typical thermal properties of crystalline polymers, whereas those synthesized with the mixtures of dicarboxylic acids were not easily crystallized. The observed miscibility behaviours showed some differences from those predicted by binary interaction model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318069
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  • 16
    Electronic Resource
    Electronic Resource
    Miscibility and mechanical properties of aryl-aliphatic polyamides/nylon 6 molecular composites (1996)
    Springer
    Polymer bulletin 37 (1996), S. 369-376 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A series of aryl-aliphatic polyamides, copoly(4,4′-diaminobenzanilide-adipamide/2,6-naphthalamide)s, with feed mole ratios of adipic acid/2,6-naphthalene dicarboxylic acid of 1/9, 3/7, and 5/5 were synthesized. A new family of molecular composites based on the synthesized aryl-aliphatic polyamides and nylon 6 has been discovered. The molecular composites were found to have at least partial miscibility between aryl-aliphatic polyamides and nylon 6. Well-defined aryl-aliphatic polyamide microfibrils a few nanometers in diameter were observed in the molecular composites. 10 wt% aryl-aliphatic polyamide clearly promoted the toughness of nylon 6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318070
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  • 17
    Electronic Resource
    Electronic Resource
    Preparation of ultrafine metal particles/polyurethane composites (1996)
    Springer
    Polymer bulletin 37 (1996), S. 377-383 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A new type of coordination polyurethane was prepared by incorporating the transition metal ions into the pyridine containing thermoplastic polyurethane films. Then the metal ions dispersed in the polyurethane matrix were reduced by controlling the exposure of the metal sites to NaBH4 under mild condition. The reduction of the polyurethane metal complex films resulted in the production of amorphous ultrafine metal powders. The size of these powders was controlled by the content of the metal ions and the polarity of the polymer matrix. A polar polymer backbone and lower metal ion concentration favored to achieve a smaller particle. It was also found that the polymer chains prohibited the excessive aggregation of the metal atoms and have protective effect on the final metal powders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318071
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  • 18
    Electronic Resource
    Electronic Resource
    Toughening mechanisms in modified epoxy resins with different crosslink densities (1996)
    Springer
    Polymer bulletin 37 (1996), S. 399-406 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Crack-tip deformation has been investigated in pre-cracked samples of core-shell rubber particle modified epoxy resins with different degrees of crosslinking. Light cross linking resulted in cavitation of the modifier, the formation of croids and extensive crack-tip yielding, whereas these deformation mechanisms were suppressed at room T in highly crosslinked specimens. A zone of particle debonding was observed in these latter at high T, but this appeared detrimental to the toughness. Indeed it was possible to increase the toughness in this case by oxygen plasma treatment of the modifier particles.
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    URL: http://dx.doi.org/10.1007/BF00318074
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  • 19
    Electronic Resource
    Electronic Resource
    Synthesis and properties of 2,2,6,6-tetramethyl-1-(1-phenethyloxy)piperidine, an initiator for living free radical styrene polymerization (1996)
    Springer
    Polymer bulletin 37 (1996), S. 451-456 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary An initiator for living free radical polymerization may be prepared by trapping the benzylic ethylbenzene radical with the stable 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) radical. The adduct, 2,2,6,6-tetramethyl-1-(1-phenethyloxy)piperidine (TMPEP), smoothly undergoes thermal fragmentation at temperatures approaching 140° C to afford an active carbon radical capable of initiating polymerization and a passive mediating nitroxyl radical to reversibly cap and preserve the propagating polymer chain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00556804
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  • 20
    Electronic Resource
    Electronic Resource
    Kinetics of association processes of d-fructose dehydrogenase onto liposome surfaces (1996)
    Springer
    Polymer bulletin 37 (1996), S. 407-414 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Association processes of D-fructose dehydrogenase (FDH) onto surfaces of liposomes which were composed of N-(5-dimethylamino-1-naphthalenesulfonyl)-L-α-dimyristoylphosphatidylethanolamide and L-α-dimyristoylphosphatidylcholine or L-α-dimyristoylphosphatidylglycerol (1:9) were investigated by the fluorescence stopped-flow technique. The association processes were divided into two relaxation processes: the faster process whose apparent rate constant monotonously increased with the concentration of FDH, and the slower process whose rate constant showed a saturation behavior. Taking the number of binding sites on the liposome surface into consideration, the corrected association rate constant of the faster process was 4.4% of the theoretical value for a binary collision, probably due to a disadvantageous surface-searching and dehydration processes on the liposome and protein surfaces. The Arrhenius plots of the rate constants both for the faster and slower steps showed a discontinuous change around the gel to liquid-crystal phase transition temperature of the liposomes. Strong influences of deformability of liposomes, and state of hydrating water molecules around polar heads, on the rate of association processes were suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318075
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  • 21
    Electronic Resource
    Electronic Resource
    Ruthenium catalyzed copolymerization of 2-acetylphenanthrene and α,ω-dienes (1996)
    Springer
    Polymer bulletin 37 (1996), S. 423-428 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Copolymers with 2-aceto-1,3-phenanthrenylene units in the chain have been directly prepared by Ru catalyzed step-growth copolymerization of 2-acetyl phenanthrene and α,ω-dienes such as 1,3-divinyltetramethyldisiloxane. Copolymers which incorporate 2-aceto-1,3-phenanthrenylene units possess higher TgS and increased thermal stability compared to analogous copolymers which have 2-aceto-5-phenyl-1,3-phenylene(biphenyl) or 2-aceto-1,3-phenylene units. Fluorescence spectra of these copolymers have been obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00556800
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  • 22
    Electronic Resource
    Electronic Resource
    Synthesis and regeneration of reactive polymers bearing triphenylphosphine dichloride functional groups using triphosgene (1996)
    Springer
    Polymer bulletin 37 (1996), S. 415-421 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A new methodology is described for the synthesis of reactive polymers bearing triphenylphosphine dichloride groups by the use of triphosgene. These materials show high reactivity for the room temperature conversion of benzyl alcohol to benzyl chloride. In one hour, yields higher than 90% were achieved using reactive copolymers with up to 25 w% divinylbenzene (DVB). The functional groups can be easily and efficiently regenerated using 1.0 mol of triphosgene for every 2.6 moles of phosphine in the polymer. Preliminary results showed up to 40% conversion of benzyl alcohol in column reactions using regenerated polymers at 5 to 10 min contact times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00556799
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  • 23
    Electronic Resource
    Electronic Resource
    Biosynthesis and characterization of poly(β-hydroxybutyrate) produced byBacillus circulans (1996)
    Springer
    Polymer bulletin 37 (1996), S. 429-435 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The biosynthesis of poly (β-hydroxybutyrate) (PHB) byBacillus circulans was carried out through cultivation in nutrient broth in a single step. $$\overline {\text{M}} {\text{v}}$$ of polymer fractions soluble in chloroform were close to 2 x 105. IR,1H and13C NMR spectra of the isolated PHB were in agreement with the assumed structure of this poly-β-hydroxyester. NMR spectroscopy pointed out a high percentage of isotactic polymer, while differential scanning calorimetry showed that the PHB was crystalline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00556801
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    Polyacrylonitrile-graft-poly(ethylene oxide) (1996)
    Springer
    Polymer bulletin 37 (1996), S. 437-442 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Graft copolymers of polyacrylonitrile (PAN) and poly(ethylene oxide) (PEO) were synthesized by radical copolymerization of acrylonitrile and methacrylate-headed poly(ethylene oxide) macromonomer. The macromonomer was prepared by reaction of methacryloyl chloride with PEO. The effects of solution concentration, initiator concentration and acrylonitrile/macromonomer molar ratio on the conversion, molecular weight and PEO branch content in the graft copolymer were studied. The graft copolymers were characterized by GPC, FTIR,13C-NMR and Kjeldhal method.
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    URL: http://dx.doi.org/10.1007/BF00556802
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  • 25
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    Copolymerization of 2,5-dimethyl-3-vinylthiophene with methyl methacrylate, styrene and isobutyl methacrylate (1996)
    Springer
    Polymer bulletin 37 (1996), S. 457-462 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The title vinyl thiophene monomer was synthesized by dehydration of the corresponding secondary alcohol. Free radical initiated copolymerizations with methyl methacrylate, styrene or isobutyl methacrylate were performed and the copolymer compositions were used in the calculation of reactivity ratios. The data was analyzed via a nonlinear least squares error-in-variables method. The 2,5-dimethyl-3-vinylthiophene was shown to have equal or slightly less reactivity than each of the monomers chosen as comonomers.
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    URL: http://dx.doi.org/10.1007/BF00556805
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    Synthesis and radical polymerization of novel vinyl monomers having the imidazoline and pyrimidine moiety (1996)
    Springer
    Polymer bulletin 37 (1996), S. 443-450 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Alkylation of the methylene bridged tetrahydropyrimidine derivatives by chloromethylstyrene produces the bridged bis(4-vinylbenzyl)-1,4,5,6,-tetrahydropyrimidinium salts in high yields. Similar procedures are used to prepare 2-imidazolinium derivatives. The quaternary salts which support functional side groups of potential biomedical interest are characterized by means of spectroscopic methods. These monomers are readily polymerized free radically in solution of dimethyl formamide at moderate temperatures. The soluble and insoluble polymers containing 2-imidazolinium and 1,4,5,6-tetrahydropyrimidinium salts were found to exhibit antibacterial activites againstEscherichia coli.
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    URL: http://dx.doi.org/10.1007/BF00556803
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  • 27
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    Synthesis, characterization of poly(allylamine)chelates with Cu(II), Co(II) and Ni(II) (1996)
    Springer
    Polymer bulletin 37 (1996), S. 463-468 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The parent polymer, poly(allylamine) as ligand polymer was employed to synthesize polychelates of heavy metal ions. The functional poly(allylamine) and its Ni(II), Co(II) and Cu(II) metal chelates were characterized by elemental analysis, FT-IR spectroscopy, TGA, and SEM. For the polychelates magnetic and conductivimetry studies were also carried out.
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    URL: http://dx.doi.org/10.1007/BF00556806
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  • 28
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    Novel chemically amplified imaging materials containing malonate pendant groups (1996)
    Springer
    Polymer bulletin 37 (1996), S. 475-482 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A new chemically amplified polymeric imaging system based on polymers containingt-butylmalonate pendant groups has been demonstrated. Both the homopolymer of di-t-butyl (vinylbenzyl)benzylmalonate and its copolymer with styrene have been tested in coatings containing a photoacid generator. Imaging experiments confirm that the materials have very high sensitivities when exposed to UV radiation near 250nm.
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    URL: http://dx.doi.org/10.1007/BF00556808
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  • 29
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    Preparation of new gels derived from poly(sucrose acrylate) with immobilized Cibacron Blue and their application in affinity chromatography (1996)
    Springer
    Polymer bulletin 37 (1996), S. 483-488 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary New pseudoaffinity chromatography supports were prepared and characterized from poly(sucrose acrylate) crosslinked with MDI or TDI and Cibacron Blue dye as ligand. Blue gels were useful in the retention of albumin and the results are reported.
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    URL: http://dx.doi.org/10.1007/BF00556809
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  • 30
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    The effect of the ethylene pressure on its reaction with 1-hexene, 1-octene and 4-methyl-1-pentene (1996)
    Springer
    Polymer bulletin 37 (1996), S. 469-474 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Copolymers of ethylene and 1-hexexe, 1-octene and 4-methyl-1-pentene were obtained using Et[In]2ZrCl2/MAO catalyst at various pressures. The increase of 1-hexene and 1-octene concentration in the feed increases catalyst activity(g/nZr.h.bar) and productivity(g/nZr.h). For 4-methyl-1-pentene the activity is independent on comonomer concentration. Increasing the ethylene pressure the productivity of the copolymerization increases and the activity shows a weak decay. Characterization of the copolymer shows that at higher pressure the cristallinity of the copolymers is higher due to lower comonomer incorporation. There is a good linear correlation of cristallinity with comonomer concentration in the feed for 1-hexene and 1-octene at a fixed pressure, but not for 4-methyl-1-pentene.
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  • 31
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    Copolymerization of styrene and methyl methacrylate with nickel acetylacetonate/methylaluminoxane catalyst system (1998)
    Springer
    Polymer bulletin 40 (1998), S. 423-429 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The present work deals with copolymerization of styrene (STY) and methyl methacrylate (MMA) catalysed by nickel acetylacetonate - Ni(acac) 2 , employing methylaluminoxane (MAO) as cocatalyst. This catalyst system presented low catalyst activities for STY homopolymerization and very high activities for MMA. It seems that the catalyst system based on Ni(acac) 2 /MAO is effective for the copolymerization of MMA and STY to give block copolymer but it also produced polystyrene and poly(methyl methacrylate) homopolymers. The polymers were characterized by 13 C NMR, GPC and FTIR. The polystyrene homopolymer was identified by IR and NMR analyses of the cyclohexane soluble fraction. The presence of absorption bands correspondent to carbonyl group and aromatic ring was observed in the IR spectrum of the acetic acid soluble part. This result is a clue that STY-MMA copolymer with low molecular weight was produced. The high molecular weight copolymer (acetic acid insoluble fraction) was also characterized by IR analysis which indicated the presence of characteristic absorption bands of carbonyl group and aromatic ring. These results were confirmed by 13 C NMR analysis.
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  • 32
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    Small-angle X-ray scattering from sodium hyaluronate in aqueous sodium chloride (1998)
    Springer
    Polymer bulletin 40 (1998), S. 555-562 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Four narrow-distribution samples of sodium hyaluronate with weight-average molecular weights M w of 3.8 × 103 to 1.1 × 104 in 0.02 and 0.1 M aqueous NaCl at 25°C have been studied by small-angle X-ray scattering. Data for their z-average radii of gyration 〈S2〉z 1/2 and particle scattering functions P(θ), together with previous 〈S2〉z data from light scattering for high molecular weights, are compared with relevant theories for the wormlike chain with or without excluded volume, using the parameters estimated previously from intrinsic viscosity ([η]) data. It is shown that for M w lower than 1.1 × 104, 〈S2〉z, P(θ), and [η] of the polysaccharide in the aqueous salts are all consistently explained by this model without excluded volume.
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    Functional polythiiranes 8. Influence of the terminal group on the thermotropic behaviour of side chain liquid crystalline polythiiranes and identification of a crystalline phase (1998)
    Springer
    Polymer bulletin 40 (1998), S. 569-574 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Three new side chain liquid crystalline polythiiranes were prepared with new substituants on the mesogenic groups. Their thermotropic liquid crystalline behaviour was studied by the usual techniques (DSC, X-ray diffraction and polarized optical microscopy). Unlike the polyoxiranes described in the literature, the size of the terminal group has no influence on the nature of the mesophases of polythiiranes ; only slight changes of the transition temperatures were observed. In this series of polymers, a phase, denoted X, appeared at temperatures below the smectic E phase, and could not be identified by usual characterization techniques. An isothermal kinetic study for the smectic E / X phase transition resulted in an Avrami exponent close to 1, suggesting a one-dimensional ordering occurred during the transformation from the smectic phase. This result, combined with other observations, helped us to assign the X phase to the crystalline phase.
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    Properties of PVC-titania hybrid materials prepared by the sol-gel process (1998)
    Springer
    Polymer bulletin 40 (1998), S. 583-590 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Hybrid materials from Polyvinyl chloride (PVC) and titania were prepared using sol-gel technique. In-situ generation of titania network in the PVC matrix was carried out by introducing required amounts of tetrapropylorthotitanate (TPOT) followed by hydrolysis/condensation of TPOT in the matrix. Homogeneous and semi-transparent films were obtained by casting and solvent evaporation. Mechanical properties of these films up to 15 wt. % titania contents were studied. The results showed an increase in the Young's modulus, length at rupture and toughness of the unplasticised PVC. However, the tensile strength and stress at break point decreased with the addition of titania contents. Thermal stability of the material was studied using dehydrochlorination (DHCl) technique and thermogravimetric analysis. The PVC samples with small amount of titania were found to be more stable as compared with the pure PVC.
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    An improvement of the Mc Bain's microbalance to study transport of solvent vapours into polymeric films (1998)
    Springer
    Polymer bulletin 40 (1998), S. 591-598 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY The sorption characteristics of benzene and cyclohexane vapours in the poly(urethane-urea) (PUU) with well defined structure were measured using an improved version of the Mc Bain's microbalance. The diffusion coefficients were calculated for the different vapour activities from the kinetics of solvent uptake, i.e. the sorption isotherms over time. Sorption and diffusion coefficients measured, showed a strong dependence of the applied vapour activity. The obtained transport parameters were discussed with regard to the polymer structure. Based on the sorption and diffusion data, the pervaporation performance of the PUU-based membrane in separation of the benzene/cyclohexane mixtures was predicted and compared with the experimental pervaporation characteristic.
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  • 36
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    Isospecific polymerization of styrene with supported nickel acetylacetonate/methylaluminoxane catalysts (1998)
    Springer
    Polymer bulletin 40 (1998), S. 689-694 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The polymerization of styrene with catalysts based on Ni(acac)2 supported on SiO2 and Al2O3 was investigated. Using catalysts based on MAO supported on silica, a highly isotactic polystyrene was obtained. Nevertheless, the Al2O3-supported catalyst can promote isospecific polymerization activated by common. alkyl aluminum compounds even by any prior support treatment with MAO.
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    Synthesis of polymer having β,β-triketone unit in the main chain and its copper (II) complex (1998)
    Springer
    Polymer bulletin 40 (1998), S. 701-706 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A novel polymer having β,β-triketone unit in the main chain was prepared by polycondensation of triethylene glycol bis(p-butoxycarbonylphenyl) ether (1) with triethylene glycol bis(p-acetylacetophenyl) ether (4). The obtained polymer was soluble in CHCl3, DMF, and DMSO. The structure of the polymer was confirmed by 1H-NMR. Insoluble brownish yellow copper (II) chelate was obtained by adding a methanol solution of copper (II) acetate to a chloroform solution of the polymer. The IR analysis and the measurement of copper content by iodometric titration showed the quantitative formation of binuclear copper (II) complex.
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  • 38
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    Synthesis and polymerization of 1-trimethylsiloxy- or 1-triphenylsiloxysilacyclobutanes (1998)
    Springer
    Polymer bulletin 40 (1998), S. 715-720 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Synthesis and polymerization behavior of 1-trimethylsiloxy- or 1-triphenylsiloxy-silacyclobutane derivatives were studied. These monomers gave polymers with reasonably high molecular weight by platinum catalyst like platinum 1,3-divinyl-1,1,3,3-tetramethyldisfloxane complex. Side-chain smectic, liquid crystalline polymer was obtained from 1-methyl-1-[3-{(4-cyanobiphenyl-4'-yl)oxy}propyl]dimethylsiloxysilacyclobutane. In the polymerization by butyllithium or phenyllithium, monomers corresponding to the amounts of the initiator were consumed, but no polymers were formed. Apparently, elimination of the trimethylsiloxy or triphenylsiloxy group occurred in the nucleophilic attack of the initiator or propagating species on the silicon atom of the monomer.
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    Preliminary investigations on polymerization catalysts composed of lanthanocene and methylaluminoxane (1998)
    Springer
    Polymer bulletin 40 (1998), S. 729-734 
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    ISSN: 1436-2449
    Keywords: (Keywords: lanthanocene; methylaluminoxane; polymerization; butadiene; isoprene; styrene.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The polymerization of butadiene(Bd), isoprene(Ip) and styrene(St) has been examined using the six catalyst systems composed of lanthanocene, (C5H9Cp)2NdCl(I), (C5H9Cp)2SmCl(II), (MeCp)2Sm OAr'(III), (Ind)2NdCl(IV), Me2Si(Ind)2NdCl(V) and (Flu)2NdCl(VI), and methylaluminoxane(MAO) respectively. All of them can be used to form the polyisoprene with molecular weights of 1 to 10 thousand and cis-1,4-unit contents of 41 to 47%. (I), (II) and (III) of them can be also used to form the polybutadiene with molecular weights of 10 to 20 thousand and cis-1,4-unit contents of 62 to 78%. In addition, the catalysts from (II) to (V) are still active for St polymerization and (II) of them gives a syndio -rich random polystyrene. It is noteworthy that (II) and (III) are active for homopolymerization of Bd, Ip and St in the same polymerization condition.
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  • 40
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    Phase transition of 2,3-O-methylcellulose (1998)
    Springer
    Polymer bulletin 40 (1998), S. 741-747 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In this work, a series of 2,3-O-methylcellulose (MC) with different DS value were prepared. Its phase transition behavior in aqueous solution was studied in terms of DS value, concentration and molecular weight. The the following conclusions were obtained. (1) All the 2,3-O-MC samples show no sol-gel transition in aqueous solution despite the molecular weight. (2) No phase separation was observed for the 2,3-O-MCs with a DS value lower than 1.0, even when the temperature was raised to 95°C. (3) The precipitation temperature is surprisingly different between 2,3-O-MCs. and other MCs possessing comparable total DS value. (4) The precipitation temperature of 2,3-O-MCs depends on the molecular weight rather than on the concentration.
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  • 41
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    Polyacrylamide obtained by plasma-induced polymerization for a possible application in enhanced oil recovery (1998)
    Springer
    Polymer bulletin 40 (1998), S. 757-764 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Ultrahigh molecular weight polyacrylamides (PAAM) were obtained by plasma-induced polymerization in water solutions. The influenceof monomer concentration, sealing pressure, initiation time and post polymerization period on polymer yield and molecular weight were investigated. The viscosity and “screen factor” measurements, as well as the thermally stimulated depolarization currents spectroscopic data of the synthesized polymers, indicate good properties as efficient viscosity modifiers in displacement of fluids for enhance oil recovery (EOR).
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  • 42
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    The relaxation behavior of amorphous PET in global chain orientation but nearly random segmental orientation (GOLR) state (1998)
    Springer
    Polymer bulletin 40 (1998), S. 773-778 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In this report, the relaxation behavior of amorphous poly(ethylene terephthalate) (PET) in global chain orientation but nearly random segmental orientation (GOLR) state is studied by infrared dichroism, optical birefringence and hot shrinkage measurements at temperatures below or up PET's glass transition temperature, Tg. The results indicate that the difference in the relaxing rate between global chains and segments is at least in ∼ 102 times order above PET's Tg (∼ 84°C), with a rough approximation; while the sudden decrease of small Δn of the sample (∼ 10−4) upon being treated at about 85 ∼ 90°C, implies us that the small Δn is closely related with the orientation of global chains.
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    In memoriam: Reimund Stadler, Editor of Polymer Bulletin (1998)
    Springer
    Polymer bulletin 41 (1998), S. 129-130 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
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  • 44
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    High molecular weight polyurethanes and a polyurethane urea based on 1,4-butanediisocyanate (1998)
    Springer
    Polymer bulletin 41 (1998), S. 131-138 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary New biomedical polyurethanes and a polyurethane urea based on Ε-caprolactone and 1,4-butanediisocyanate have been developed. On degradation, only non-toxic products are produced. The polyurethane urea with poly(Ε-caprolactone) soft segments and butanediisocyanate/butanediamine hard segments shows a high tensile strength, a high modulus and a high resistance to tearing but as a result of the strong interactions between the solvent and the polymer processing is difficult. When butanediamine is replaced by butanediol in the chain extension step, a processible polyurethane is obtained but the polymer lacks the desired mechanical properties for biomedical applications. By chain extending with a longer urethane diol block, a processible polymer was obtained with mechanical properties comparable to the polyurethane urea. This polyurethane has been made porous and can be used as a meniscal prosthesis.
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  • 45
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    Inversion of stereoselectivity in 1,3-butadiene polymerization with a niobium catalyst induced by a change in the solvent system (1998)
    Springer
    Polymer bulletin 41 (1998), S. 175-182 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Catalytic 1,3-butadiene polymerization systems can be obtained with the new complex [NbO(C16H11O6 −)(C2O4 2−)] as a catalyst. When the catalysis occurs in a homogeneous medium (toluene as a solvent) in conjunction with AlEt2Cl, cis-1,4-polybutadiene is obtained. A remarkable inversion of stereoselectivity has been observed when the catalysis is carried out in a two phase system with the molten salt AlCl3.1-methyl-3-n-butyl-imidazolium chloride (MBIC) as a solvent and AlEt2Cl as a cocatalyst, giving the trans 1,4-polybutadiene.
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  • 46
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    Use of branched aliphatic linkers for the preparation of selective chiral media for the HPLC separation of enantiomers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 183-189 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Highly branched aliphatic molecules have been used for the first time as tethers in the preparation of polymeric chiral stationary phases. Attachment of a specifically designed chiral selector to organic porous polymer beads through a branched linker substantially increases the enantioselectivity compared to that of the equivalent separation medium with a traditional linear tether.
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  • 47
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    An EPR study of polysaccharide copper(II) complexes in composite dextran/epichlorohydrin gels (1998)
    Springer
    Polymer bulletin 41 (1998), S. 199-206 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The EPR spectra of composite dextran and carboxymethyldextran gels were studied in order to identify the functional groups involved in copper(II) complexation depending on pH. The porous structure resulting from crosslinking of polymer chains of dextran, via epichlorohydrin, forces the immobilization of Cu2+ ions surrounded by different oxygen groups of the polymer gel matrix. The different polynuclear structures are postulated to be formed depending on the type of polysaccharide derivatives. The results indicate that carboxyl and deprotonated hydroxyl groups participate in the complex formation.
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    Electronic absorption spectroscopy of liquid systems containing polystyrene and polyacrylonitrile 1. Individual polymer solutions (1998)
    Springer
    Polymer bulletin 41 (1998), S. 207-213 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Individual polystyrene (PS) and polyacrylonitrile (PAN) solutions in N,N-dimethylformamide (DMF) were studied by electronic absorption spectroscopy. Upon increasing the polymer concentration in the PS-DMF binary system a bathochromic shift of the band at about 260 nm was found. This spectral effect could be explained by an association of PS phenyl groups and/or by a complex formation between DMF and PS. The UV spectrum of PAN in DMF solution was interpreted in terms of the variety of possible donor-acceptor complex formations. The specific intermolecular interactions in the investigated binary liquid systems were discussed on the basis of the spectral data.
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    URL: http://dx.doi.org/10.1007/s002890050353
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    Swelling behavior of emulsion polymer particles: comparison between fully cross-linked and partially cross-linked poly(acrylate) latexes (1998)
    Springer
    Polymer bulletin 41 (1998), S. 231-237 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Measurement of swelling is used to estimate the extent of cross-linking of latex particles prepared by emulsion polymerization. In this paper we report swelling data as a function of solvent activity for two latexes: (1) a poly(butylacrylate) (PBA) latex, and (2) a poly(isodecylacrylate) latex. In the latter case comparison is made between the swelling behavior of fully cross-linked, i.e., networks without free polymer chains, and partially cross-linked latexes. It is demonstrated that the equilibrium swelling properties are only slightly affected by the presence of uncross-linked chains. Swelling gives reliable results for the cross-link density only if the latex does not contain free chains.
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    URL: http://dx.doi.org/10.1007/s002890050356
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    The strength of the tailored polymer/inclusion interface in polymer composites evaluated in situ by acoustic emission (1998)
    Springer
    Polymer bulletin 41 (1998), S. 247-252 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A correlation between interface strength and data of acoustic emission measurements in particle filled polymer composites was found. The method allows the evaluation of the interface strength in situ in polymer composite specimens at uniaxial loading. The measurements have shown that the tailored interface with the monomolecular tethered polymer layers of various grafting density change the mechanism of microdefect formation.
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    URL: http://dx.doi.org/10.1007/s002890050358
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    Block copolymerization of tetrahydrofuran with δ-valerolactone by the samarium iodide-induced transformation (1996)
    Springer
    Polymer bulletin 37 (1996), S. 597-601 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Polymerization behavior of δ-valerolactone (VL) with alkylsamarium (RSmI2) was studied, and its application to the block copolymerization of tetrahydrofuran (THF) with VL was examined. Polymerization of VL by butylsamarium gave the corresponding poly(VL) in good yield. The yield increased with increasing the concentration of VL and decreasing the polymerization temperature, resulting from the equilibrium between VL and poly(VL). The decrease in the molecular weight of poly(VL) by prolonging the polymerization time indicated the existence of back-biting reaction to form cyclic oligomers. The polymerization of VL with poly(THF)-macroanion obtained by the two-electron reduction of the propagation center of living poly(THF) with SmI2 led to the block copolymer of THF with VL. The initiation efficiency of VL-polymerization was almost quantitative, and the unit ratio of THF and VL-segments could be controlled by both the polymerization time of THF and the amounts of VL.
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    URL: http://dx.doi.org/10.1007/BF00296604
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    The synthesis and thermal phase transition behavior of poly(N-isopropylacrylamide)-b-poly(ethylene oxide) (1998)
    Springer
    Polymer bulletin 40 (1998), S. 455-460 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary By using the redox reaction between Ce(IV) and terminal -CH2OH groups of polyethylene oxide(PEO), block copolymers composed of poly(N-isopropylacrylamide)(PNiPAAm) and poly(ethylene oxide) was prepared. The aqueous solution of the block copolymers exhibited thermal phase transition and the phase transition temperature of these block copolymers became higher than the PNiPAAm homopolymer.
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    URL: http://dx.doi.org/10.1007/s002890050276
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    Side-chain liquid crystalline polyurethanes on the basis of biphenyl mesogenic units (1998)
    Springer
    Polymer bulletin 40 (1998), S. 469-476 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Liquid crystalline diols containing a biphenyl mesogenic core, methoxy or cyano terminal groups and spacers of various lengths were synthesized and used for the preparation of side-chain thermotropic polyurethanes. The structure of the synthesized diols and polymers was confirmed by elemental analysis, FTIR and NMR spectroscopy. Phase transition temperatures were studied by DSC, while optical textures were characterized by polarizing microscopy. A smectic type arrangement was found for the mesophases of all products.
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    URL: http://dx.doi.org/10.1007/s002890050278
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    Polyurethane toughened polylactide (1998)
    Springer
    Polymer bulletin 40 (1998), S. 485-490 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Brittle polylactide (PLA) was toughened by introducing 5 wt % of a poly(ɛ-caprolactone)(PCL) diol- and triol-based polyurethane (PU) network. The extent of cross-linking of the PU was varied by changing the ratio between diol and triol. The effects of the PU content and its crosslink density on the mechanical properties and the toughness of PU/PLA blends were investigated. Maximum toughness of PU/PLA blends, an order of magnitute higher than that of pure PLA, could be achieved by the use of a proper amount of PU and a proper extent of cross-linking.
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    URL: http://dx.doi.org/10.1007/s002890050280
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    Effects of cyclization and electrostatic interactions on the termination rate of macroradicals in free-radical crosslinking copolymerization (1998)
    Springer
    Polymer bulletin 40 (1998), S. 491-498 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Effects of cyclization and ionic group contents on the termination rate of macroradicals formed at zero monomer conversion were investigated. For this purpose, the pregel regime of free-radical methyl methacrylate / ethylene glycol dimethacrylate (MMA/EGDM) and acrylamide / N,N'-methylenebisacrylamide (AAm/BAAm) copolymerization systems was studied by means of the dilatometric technique. To eliminate the chain-length dependent variation of the termination rates, different sets of experiments were carried out each at a fixed monomer and initiator concentration. At low crosslinker contents, the termination rate of zero-conversion macroradicals was enhanced in crosslinking copolymerizations compared to linear polymerization. This is due to the cyclization reactions which reduce the size of the macroradical coils and thus, enhance the termination rates due to the lowering of the thermodynamic excluded volume effect. As the amount of the crosslinker increases, an enhancement in the initial rate of polymerization is observed in all series of experiments, indicating that steric effects on segmental diffusion dominate at high crosslinker contents. The results also indicate a slower rate of termination of ionic macroradicals compared to the non-ionic radicals of the same molecular weight and points the significance of the thermodynamic excluded volume effect on rising the ionic group content.
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    URL: http://dx.doi.org/10.1007/s002890050281
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    Thermal stabilities of end groups in hydroxyalkyl terminated polydimethylsiloxane oligomers (1998)
    Springer
    Polymer bulletin 40 (1998), S. 525-532 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Thermal stabilities of α,ω-hydroxypropyl, α,ω-hydroxybutyl, α,ω-2-hydroxypentyl and α,ω-hydroxyhexyl terminated polydimethylsiloxane (PDMS) oligomers were studied. Hydroxypropyl and hydroxybutyl terminated polydimethylsiloxane oligomers showed degradation upon heating, through the loss of functional end groups as determined by FT-IR spectroscopy and gel permeation chromatography. α,ω-Hydroxyhexyl and α,ω-2-hydroxypentyl terminated polydimethylsiloxane oligomers were stable under similar conditions. Instability of the end groups is due to the back biting of the terminal silicon in the PDMS by the primary hydroxyl oxygen, leading to the formation of 5 and 6 membered, stable, heterocylic compounds. Loss of end groups also resulted in a dramatic increase in the molecular weights of the oligomers produced, as determined by gel permeation chromatography.
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    URL: http://dx.doi.org/10.1007/s002890050286
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    Use of mass spectrometry for the analysis of molecular weight distribution and macrocycles in fuctionalized oligo-ɛ-caprolactones synthesized by heterogeneous AROP in protic conditions (1998)
    Springer
    Polymer bulletin 40 (1998), S. 541-548 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary. Functionalized oligo-ɛ-caprolactones synthesized by heterogeneous coordinated anionic ring opening polymerization (AROP) in protic conditions have been analyzed by mass spectrometry in order to investigate the molecular weight distribution as well as the possible occurrence of macrocycles. Mass spectra obtained from LSIMS revealed the presence of fragmentation products and some of them have been identified. Macrocycles were also detected. Nevertheless, ESI and MALDI-TOF spectrometries do not confirm the presence of macrocycles in the samples. The same results have been obtained by analysis of commercially available polycaprolactones.
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    URL: http://dx.doi.org/10.1007/s002890050288
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    Apparent contrast reversal in tapping mode atomic force microscope images on films of polystyrene-b-polyisoprene-b-polystyrene (1998)
    Springer
    Polymer bulletin 40 (1998), S. 549-554 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Thin films of phase separated polystyrene-b-polyisoprene-b-polystyrene block copolymers were studied by tapping mode atomic force microscopy. The relative contrast in height and phase mode images of the phase separated regions was found to be very sensitive to changes in the operating conditions of the microscope. Contrast variations and reversals were observed for height and phase mode images as a function of the set-point amplitude ratio and drive frequency. No unique height or phase contrast was observed for the the tri-block copolymer system examined in this study.
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    URL: http://dx.doi.org/10.1007/s002890050289
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    Dielectric studies on allyl methacrylate-methyl methacrylate copolymers in a slightly polar medium (1998)
    Springer
    Polymer bulletin 40 (1998), S. 563-568 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Dielectric constants of allyl methacrylate-methyl methacrylate copolymers are measured in toluene solution at a constant frequency of 2 MHz, within a wide temperature range (20–70°C). Soluble copolymers have been prepared by group transfer copolymerization. Dipole moments are calculated from Guggenheim-Smith equation. The effects of allyl group on the dipole moments of copolymers in a slightly polar medium are discussed.
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    URL: http://dx.doi.org/10.1007/s002890050291
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    Influence of some aromatic amino acids on the swelling behavior of acrylamide/maleic acid hydrogel (1998)
    Springer
    Polymer bulletin 40 (1998), S. 575-581 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Influence of some aromatic amino acids (histidine, phenylalanine and tryptophan) on the swelling behavior of acrylamide/maleic acid hydrogel (AAm/MA) prepared by γ-radiation was investigated. Swelling tests of AAm/MA hydrogel were made in buffer solutions and amino acid solutions at various pH at 37°C. The pH values are ionization of α-carboxyl groups (pK'1), α-amino groups (pK'2) and, isoelectric points (pI) of amino acids. The swelling of AAm/MA hydrogel increased when pH values of solutions were increased. The value of equilibrium swelling of AAm/MA hydrogel was 1035% at pH 10 buffer, while it was 880% at pH 2 buffer. The values of equilibrium swelling of AAm/MA hydrogel in phenylalanine, tryptophan and histidine solutions varied among 1130–1245% at pH 10, while they were among 790–975% at pH 2. The rate constant of swelling, diffusional exponent, network parameter and, diffusion and intrinsic diffusion coefficient were calculated by swelling kinetics. Diffusion of the penetrants into the hydrogel was found to be non-Fickian character. The diffusion coefficients of the hydrogel varied between 3.33×10−6– 7.71×10−6 cm 2s−1, while the intrinsic diffusion coefficients waried between 4.03×10−6– 8.48×10−6 cm 2s−1.
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    URL: http://dx.doi.org/10.1007/s002890050293
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    Study of rubber-modified epoxy resin using thermally stimulated current (1998)
    Springer
    Polymer bulletin 40 (1998), S. 599-605 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In order to characterize the low temperature relaxation of epoxy resin modified with amine-terminated butadiene acrylonitrile copolymers (ATBN), thermally stimulated current (TSC) and relaxation map analysis (RMA) were investigated. Four relaxation peaks at around −140, −100, −60 and 0°C were observed as the indication of γ-, β-relaxation of epoxy resin, Tg, new unknown peak of ATBN, respectively. The unknown peak at around 0°C was observed due to dipole orientation. The RMA data was showed that compensation temperature (Tc) and degree-of-disorder (DOD) were increased with increasing the content of acrylonitrile and ATBN, whereas the compensation time (τc) was decreased. It can be concluded that the cooperative molecular motion in cured epoxy resin was more active as the concentration of acrylonitrile and ATBN content increases.
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    URL: http://dx.doi.org/10.1007/s002890050296
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    Conducting copolymers of polypyrrole/polytetrahydrofuran (1998)
    Springer
    Polymer bulletin 40 (1998), S. 639-645 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Bifunctional living polytetrahydrofuran (PTHF) was terminated with potassium salt of pyrrole to yield polymers with electrochemically active end groups. These polymers were employed in the second stage to obtain conducting polypyrrole/polytetrahydrofuran block copolymers with short and long polytetrahydrofuran segments by potentiostatic anodic polymerization of pyrrole in different electrolytic media. Syntheses of block copolymers were achieved in media where tetrabutylammonium fluoroborate, sodium perchlorate and sodium p-toluenesulfonate were used as the supporting electrolytes. Characterizations were based on DSC, TGA, SEM, FTIR, and CV analyses. No significant effect of the chain length of polytetrahydrofuran segments on the properties of the copolymers was observed; however, thermal, electrochemical behaviors, and surface morphologies of the films were greatly affected by the supporting electrolytes.
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    Effect of the molecular structure of graft copolymer on the interfacial behavior between two immiscible homopolymers: A Monte Carlo simulation (1998)
    Springer
    Polymer bulletin 40 (1998), S. 607-612 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effects of molecular structure of graft copolymer on the interfacial properties are investigated using a Monte Carlo simulation. The interfacial activity is analyzed by calculating the surface coverage and the concentration profile of graft copolymer at the interface. At low interaction energy between two segments, the graft copolymer having fewer grafting sites and longer grafting chains locates better at the interface than the graft copolymer having more grafting sites and shorter grafting chain. At high interaction energy, this situation is reversed: the graft copolymer with more grafting sites locates better than the copolymer with fewer grafting sites.
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    URL: http://dx.doi.org/10.1007/s002890050297
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    Syndiotactic polymerization of styrene with CpTiCl2(OPri)/methylaluminoxane (1996)
    Springer
    Polymer bulletin 37 (1996), S. 719-721 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary CpTiCl2(OPri) was a very active catalyst for syndiotactic polymerization of styrene when activated with methyl aluminoxane (MAO). The catalyst activity and syndiospecificity of CpTiCl2(OPri)/MAO were about 107 g PS / mol Ti·mol S·h and about 95% respectively, both higher than those of CpTiCl3 / MAO.
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    URL: http://dx.doi.org/10.1007/BF00295768
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    Cationic polymerization of styrene and indene in iodine/liquid sulfur dioxide system (1996)
    Springer
    Polymer bulletin 37 (1996), S. 729-735 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The cationic polymerizations of indene (Ind) and styrene (Sty) initiated by iodine (I2) in liquid sulfur dioxide (SO2) were investigated. Reactions involving Ind were characterized by termination by neutralization between the growing carbocationic species and the nucleophilic counteranion, at low temperature. Sty polymerization is also termination-dominated and gives low conversion at -20°C. High resolution gas chromatography coupled with mass spectrometry (HGC-MS) analysis of non polymeric material in the Sty polymerization suggested that initiation of Sty polymerization involves the formation of 1,2 diiodide adduct prior to initiation with HI.
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    Synthesis and characterization of the novel cellulose derivative dansyl cellulose (1996)
    Springer
    Polymer bulletin 37 (1996), S. 743-749 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Novel, soluble 5-dimethylamino-1-naphthalenesulfonyl esters of cellulose (2) with a degree of substitution from 0.67 to 1.59 were prepared by esterification of cellulose dissolved in N,N-dimethylacetamide/LiCl solvent system and characterized by means of FTIR-as well as 1H and 13C NMR-spectroscopy. The remaining OH groups of 2 can be fully acetylated in pyridine using N,N-dimethylaminopyridine as a catalyst. The polymers show typical fluorescence and absorption spectra with absorptions at 217, 250 and 317 nm which are in good agreement with quantum chemical calculations.
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    Poly(styrene)s with oligo(ethylene oxide) side chains as catalysts for phase transfer reactions (1996)
    Springer
    Polymer bulletin 37 (1996), S. 759-763 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A very interesting part within the wide field of chemical reactions are-catalyzed reactions. To find an effective low cost catalyst for various applications is a primary goal of many workers. Polymer chemistry is able to provide systems with qualities not known for monomeric catalysts. Especially in heterogenic systems the use of polymeric catalysts has many advantages such as easy separation for reuse or low toxicity. A special type of heterogenic catalysis is the phase transfer catalysis. Comb polymers of poly(styrene) with oligo(ethylene oxide) side chains were investigated for their ability as phase transfer catalysts.
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    Zn lactate as initiator of dl-lactide ring opening polymerization and comparison with Sn octoate (1996)
    Springer
    Polymer bulletin 37 (1996), S. 771-776 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Zn lactate, 3H2O and dehydrated Zn lactate were used as initiator to polymerize DL-lactide under various conditions. It is shown that the latter does polymerize DL-lactide up to high molecular weight at a slower rate than Sn octoate. Zn lactate being formed when lactic acid is allowed to react with Zn metal, it is believed that the active species in Zn metal initiation is Zn lactate. Comparison was made of the two poly(DL-lactide) initiated with Zn metal and Sn octoate respectively and selected to have almost similar characteristics. It is shown that degradation characteristics of the two polymers are different, especially water uptake and rate of heterogeneous degradation. It is further shown that residual Sn concentrated within the matrix remnants whereas the content in Zn remained constant according to degradation controlled release.
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    Vinyltrimethylsilane-co-N-vinyl-2-pyrrolidone and vinyltrimethoxysilane-co-N-vinyl-2-pyrrolidone copolymers Synthesis and reactivity ratios (1998)
    Springer
    Polymer bulletin 40 (1998), S. 707-713 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Copolymers containing vinyltrimethylsilane and vinyltrimethoxysilane with N-vinyl-2-pyrrolidone at different compositions were synthesized and characterized. The reactivity ratios was estimated by using the classical Fineman-Ross and Kelen Tüdos linear fitting procedures. These parameters were also estimated through a computer program based on nonlinear minimization algorithm, starting from the r1 and r2 values obtained by the former procedures. The analysis of the results allow us to interpret the reactivity behaviour of these polymers in terms of the relative reactivity of the substiuents. The effect of the chemical structure of the polymer side group is discussed in terms of the different contributions to the stabilization of the radical intermediates.
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    Highly Pb(II)-selective resin based on crosslinked poly(acrylamido glycolic acid) copolymer (1998)
    Springer
    Polymer bulletin 40 (1998), S. 721-728 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY The crosslinked poly(acrylamido glycolic acid) (180-250 µm) was used in the adsorption/desorption studies. Adsorption rate, capacity of the resin for the selected metal ions, i.e. Cd(III), Zn(II), Hg(II), Pb(II), and Cr(III) were investigated in aqueous media. At different pH values (1.0–5.0) very high adsorption was observed for Pb(II) at pH 3 and 5. The adsorption equilibrium was rapidly achieved in about 5–10 min. However, when the Pb(II) ions competed with Cd(II) (in the case of the adsorption from their binary mixture) the amount of adsorption for Pb(II) decreased. Desorption of Pb(II) was studied by using 1-4M HNO3 and 1-4M HClO4. High desorption ratios (more than 90%) were achieved in all cases. Adsorption/desorption cycles showed the possibility of repeated use of this resin.
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    Dehydrogenative polycondensation of telechelically bis(dimethylsilyl)functionalized oligo(dimethylsiloxane)s or aromatics and 1,3,3,5,5,7,7,7-octamethyltetrasiloxane (1997)
    Springer
    Polymer bulletin 38 (1997), S. 1-5 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Telechelically bis(hydrodimethylsilyl)-functionalized oligo(dimethylsiloxane)s or aromatics were found to give polymers constituting of alternating disilylene and oligodimethylsiloxane or 4,4′-diylaromatics as repeating units by dehydrogenative coupling reaction in the presence of palladium dibenzylideneacetone complex. The same catalyst gave polysilylenes with trisiloxane pendant from 1,1-dihydro-1,3,3,5,5,7,7,7-octamethyltetrasiloxane.
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    URL: http://dx.doi.org/10.1007/s002890050011
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    Synthesis of nanosize poly(methyl methacrylate) microlatexes with high polymer content by a modified microemulsion polymerization (1998)
    Springer
    Polymer bulletin 40 (1998), S. 749-756 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Nanosize poly(methyl methacrylate) (PMMA) microlatexes with high PMMA/surfactant ratio have been successfully prepared by a modified microemulsion polymerization, i.e., continuous and slow addition of monomer (MMA) to the polymerizing MMA microemulsion with mild stirring. Number-average diameters of 33–46 nm with narrow polydispersity (Dv/Dn= 1.1) and polymer content of 6–24 wt% were achieved using low levels of surfactant (dodecyltrimethylammonium bromide, DTAB) — less than 1 wt% of the reaction mixture. Particle diameter depended on polymerization temperature, MMA content, and concentrations of initiator and surfactant. Larger particles wereformed when temperature was too high, initiator concentration was too high, or surfactant concentration was too low.
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    URL: http://dx.doi.org/10.1007/s002890050318
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  • 73
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    Synthesis of polyorganosiloxane particles (1997)
    Springer
    Polymer bulletin 38 (1997), S. 23-25 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hybrid particles have been synthesized from methyltriethoxysilane (MTEOS) by the sol-gel process. The particle size, size distribution, particle surface morphology conductivity and pH of the reaction solution at different reaction times were determined. Compared with tetraethyl orthosilicate (TEOS) and p-(chloromethyl)phenyl-trimethoxysilane (CMPTOS), MTEOS has a slower hydrolysis rate.
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    URL: http://dx.doi.org/10.1007/s002890050014
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  • 74
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    Polymerization of 4-n-alkylstyrenes with typical Ziegler-Natta and metallocene catalysts (1997)
    Springer
    Polymer bulletin 38 (1997), S. 43-48 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Polymerization of 4-n-alkylstyrenes (alkyl side group; methyl, ethyl, propyl and buthyl) was carried out with the η-C5(CH3)5TiCl3-methylaluminoxane (MAO) and TiCl3-triethylaluminum (TEA) catalyst systems. When the η-C5(CH3)5TiCl3-MAO catalyst was used, the stereoregularity of resulting polymers markedly depended on the length of substituted alkyl groups, i.e., the catalyst gave highly syndiotactic poly(4-methylstyrene), but produced atactic polymers for the monomers with ethyl, propyl and buthyl substituents. On the other hand, all the poly(4-n-alkylstyrene)s obtained with the TiCl3-TEA catalyst were highly isotactic. As a result, a large difference was observed in the thermal properties of polymers obtained between the two catalyst systems.
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    URL: http://dx.doi.org/10.1007/s002890050017
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    Enzyme-catalyzed peptide syntheses in aqueous polymer two-phase systems (1997)
    Springer
    Polymer bulletin 38 (1997), S. 49-53 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Peptide synthesis in the aqueous polymer two-phase system was examined. Water soluble polymers adopted were dextran and polyethyleneglycol (PEG). By the modification of a proteolytic enzyme, trypsin, with dextran carrying a very small number of carboxyl groups, a separation of the enzyme from its peptide product, N-benzoyl-L-arginine glycinamide, which is relatively more soluble in a PEG phase could be realized. This separation drastically reduced a so-called "mass-law" effect, and increased the yield of the reaction product. The aqueous polymer two-phase system would be useful to enhance the usefulness of biocatalysts in organic syntheses.
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    URL: http://dx.doi.org/10.1007/s002890050018
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  • 76
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    Effect of the crosslinking with 1,1,1-trimethylolpropane trimethacrylate on 5-fluorouracil release from poly(2-hydroxyethyl methacrylate) hydrogels (1997)
    Springer
    Polymer bulletin 38 (1997), S. 55-62 
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    ISSN: 1436-2449
    Keywords: Key words: Poly(2-hydroxyethyl methacrylate) (PHEMA) – 5-fluorouracil (5-FU) – 1,1,1-trimethylolpropane trimethacrylate (TPT) – hydrogel – controlled release – diffusion coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The aim of this study is to examine the influence of crosslinking density on 5-Fluorouracil release from poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels crosslinked with 1,1,1-trimethylolpropane trimethacrylate (TPT). PHEMA hydrogels were synthesized by bulk polymerization with different proportions of TPT (1 – 10 wt%) as crosslinker agent and ammonium persulphate as initiator, enabling polymerization in the feed mixture in the presence of water. As a result, 5-FU could be trapped by including it as a sodium salt in the feed mixture of polymerization. Discs with 5-FU loads between 1 – 16 mg/disc were obtained. Swelling and 5-FU release kinetics studies were carried out in saline solution at 310 K. The diffusion studies were in accordance with Fick's second law during the initial stages, enabling the diffusion coefficients of the process to be determined. The time required for discs to reach total 5-FU release was between 35 h and 160 h and was a function of crosslinking density of the gels and 5-FU load of the discs.
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    URL: http://dx.doi.org/10.1007/s002890050019
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  • 77
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    Effect of surfactant concentration, pH, and shear rate on the rheological properties of aqueous systems of a hydrophobically modified chitosan and its unmodified analogue (1997)
    Springer
    Polymer bulletin 38 (1997), S. 71-79 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Oscillatory shear, shear relaxation and viscosity experiments have been carried out on semidilute solutions of chitosan and on a hydrophobically modified analogue (HM-chitosan) in 1% acetic acid. This was done in the presence of various amounts of cetyltrimethylammonium bromide (CTAB) and at different pH values. All the rheological measurements on the HM-chitosan solutions revealed significant polymer-surfactant interaction and pH effects. The observed rheological effects were least pronounced at pH ≈ 4, while a strong viscoelastic response was found at pH values of 1 and 5 in HM-chitosan solutions of low surfactant concentration. At these conditions, significant shear-thinning effects were observed. In semidilute solutions of unmodified chitosan, the influence of pH, surfactant concentration and shear rate on the rheological properties was moderate or insignificant.
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    URL: http://dx.doi.org/10.1007/s002890050021
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  • 78
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    Electrical conductivity of polystyrene/styrene-butadiene block copolymer blends containing carbon black (1997)
    Springer
    Polymer bulletin 38 (1997), S. 95-100 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The electrical resistivity and mechanical properties of carbon black (CB)-filled polystyrene (PS)/styrene-butadiene block copolymer (SB) blends have been studied. Good electrical performance was achieved with pure SB and PS/SB blends indicating an inhomogeneity of these materials and the heterogeneous micro-dispersion of the CB particles. The percolation threshold of the filler inside SB or PS/SB blends is around 3.6 wt%, which is lower than that expected for incompatible PS/PBD blend. The addition of small amount CB decreases the elongation at break of PS/SB blends indicating some disturbance at the interface of these compatible material.
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    URL: http://dx.doi.org/10.1007/s002890050024
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  • 79
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    Homo-, co- and terpolymerization of 1,5-hexadiene using a methylalumoxane activated mono-Cp-amido-complex (1997)
    Springer
    Polymer bulletin 38 (1997), S. 141-148 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Homo- and copolymerizations of 1,5-hexadiene with ethene and styrene using halfsandwich metallocene catalyst Me2Si(Me4Cp)(N-tert.-butyl)TiCl2/MAO (Cp = cyclopentadienyl, Me = methyl, MAO = methylalumoxane) were investigated. According to 13C-NMR spectroscopic microstructure analysis, cyclopolymerization of 1,5-hexadiene afforded randomly distributed cis- and trans-cyclopentane rings in the homo- and copolymer backbone. 1,5-hexadiene incorporation reached 52 mol-%. The ratio of vinyl side chains to cyclopentane rings was controlled by 1,5-hexadiene concentration, where low 1,5-hexadiene concentration promoted cyclopolymerization. Copolymer glass transition temperatures increased with increasing content of cyclic units in the backbone. Styrene was used successfully as termonomer in ethene/1,5-hexadiene polymerization, resulting in a semicrystalline terpolymer with cyclic and styrenic units in the polymer backbone.
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    URL: http://dx.doi.org/10.1007/s002890050030
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  • 80
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    Synthesis and properties of polyurethanes containing phosphatidylcholine analogues in the main chains and long-chain alkyl groups in the side chains (1997)
    Springer
    Polymer bulletin 38 (1997), S. 133-140 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. New phospholipid polyurethanes containing phosphatidylcholine analogues in the main chains and octyl or oleyl groups in the side chains were synthesized by the addition polymerization of diols, bis[2-(2-hydroxyethyldimethylammonio)ethyl]2-octyl-1,3-propanediphosphate or bis[2-(2-hydroxyethyldimethylammonio)ethyl]2-oleyl-1,3-propanediphosphate, with diisocyanates such as 4,4′-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and 2,4-tolylene diisocyanate (TDI). The new phospholipid diols and polyurethanes were characterized by their IR and 1H-NMR spectral data and elemental analysis. The new phospholipid polyurethanes exhibit common polyelectrolyte viscosity behaviours revealed by viscosity measurements. Moreover, π-A isotherms for these polyurethanes were also prepared.
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    URL: http://dx.doi.org/10.1007/s002890050029
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  • 81
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    Photoinitiated cationic ring-opening polymerization of a cyclosiloxane (1997)
    Springer
    Polymer bulletin 38 (1997), S. 165-168 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hexamethylcyclotrisiloxane was found to undergo photoinitiated cationic ring-opening polymerization in solution and bulk, upon exposure to UV radiation, in the presence of either sulfonium or iodonium salts or an iminosulfonate derivative. Glass transition temperatures were below − 100 °C. Molecular weights, determined by size exclusion chromatography relative to polystyrene standards, increased with photolysis lamp intensity. Use of an iodonium photoinitiator afforded poly(dimethylsiloxane) with Mn = 172,000. Polymerization of hexamethylcyclotrisiloxane was accompanied by a small increase in volume (3 – 4%).
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    URL: http://dx.doi.org/10.1007/s002890050033
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  • 82
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    An alternating copolymer for a blue light-emitting diode (1997)
    Springer
    Polymer bulletin 38 (1997), S. 169-176 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. An alternating copolymer composed of 9,9′-dihexylfluorene and N-2-ethylhexyl carbazole was synthesized to use as an emissive polymer in a light-emitting diode (LED). The copolymer is soluble in organic solvents and spin-cast to make a fine film. An LED fabricated by sandwiching the alternating copolymer between indium-tin oxide and aluminum emits a white color with the full width at half maximum of 150 nm. The electroluminescence spectrum becomes simplified to have an emission peak at 460 nm for fine blue color when the copolymer is blended with poly(vinylcarbazole) with a ratio of 1 to 4 before the use as an emissive layer. The forward bias turn-on voltage for the LED is 13, and quantum efficiency is 0.002%.
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    URL: http://dx.doi.org/10.1007/s002890050034
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  • 83
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    Rheological characteristics of aqueous solutions of mixtures of chitosan and polyoxyethylene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 115-121 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The rheological characteristics of aqueous solutions of chitosan and polyoxyethylene (POE) with molecular weight in the range of 105–106, as well as of their mixtures are described. It is found that the solutions of each polymer as well as of their mixtures exhibit pseudoplastic non-Newtonian behaviour which is described by the Ostwald-de-Waele model. It is proposed that the chitosan macromolecules determine the rheological behavior of the chitosan/POE mixtures.
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    URL: http://dx.doi.org/10.1007/s002890050340
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    Estimation of the effective conjugation length of oligo-p-phenylenes from specific refractive index increments of solutions (1998)
    Springer
    Polymer bulletin 41 (1998), S. 123-128 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary An unusually strong molecular weight dependence of the specific refractive index increment which has been reported for solutions of oligomers (M 〈 103) of p-2-methyl phenylene is attributed to the exaltation of polarizability of phenylene units. The saturation length is estimated to be l s≅ 6 phenylene units.
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    New imide-copolymers with coronand structure (1998)
    Springer
    Polymer bulletin 41 (1998), S. 153-160 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY The Diels-Alder reaction of bis-(2-pyrone) 2 with various aliphatic and aromatic bismaleimides 1 in dilute solution was carried out to produce linear soluble copolymers with a coronand structure. NMR spectra and model reactions confirm the structure 4 (3). The polymers show weight losses at about 440°C determined by thermogravimetric analysis (Tab. 1).
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    A novel side chain liquid crystalline polyurethane (1998)
    Springer
    Polymer bulletin 41 (1998), S. 139-144 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Side chain liquid crystalline polyurethanes (SCLP) without flexible spacer were synthesized by a two step block copolymerization reaction. The polyurethanes were based on azobenzene-type mesogenic diol chain extender (DR-19), a poly(tetramethylene oxide) (PTMO) soft segment, and different diisocyanates, including 4,4-diphenylmethane diisocyanate (MDI) and hexamethylene diisocyanate (HDI). The polyurethane samples obtained from DR-19 or DR-19 and PTMO with HDI had mesomorphic phases as determined by DSC and polarizing microscopy.
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    URL: http://dx.doi.org/10.1007/s002890050344
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  • 87
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    Grafting phosphonated thiol on hydroxy telechelic polybutadiene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 145-151 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary An hydroxytelechelic polybutadiene (PBHT) of 1200 molecular weight has been modified by the phosphonated thiol HS-(CH2)3-PO(OC2H5)2 (I). The thiol (I) was prepared in three steps: phosphonation of allyl bromide, addition of thioacetic acid and hydrolysis. The grafting rate of (I) on PBHT has been calculated by sulfur analysis and by 1H NMR. The results confirmed that the 1,2 double bonds are 10 times more reactive than the 1,4. The method led to new macromolecular polyols containing between 3 and 5 % in weight of phosphorous. These new long polyols should be very interesting in order to prepare fire retardant polyurethane networks.
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  • 88
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    Preparation and properties of poly(methyl methacrylate) crosslinked with multimonomers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 161-166 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Multimonomers, such as poly(2-acryloyloxyethyl methacrylate) and poly(2-methacryloyloxyethyl methacrylate) were used as new macrocrosslinkers to crosslink poly(methyl methacrylate). The influence of the kind of macrocrosslinker, its molecular weight and amount on the crosslink density and some properties of the crosslinked polymers networks, such as swelling and mechanical properties (tensile strength and elongation at break) have been examined. The results obtained were compared with those for poly(methyl methacrylate) crosslinked with conventional crosslinker 1,4-butanediol dimethacrylate.
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    Synthesis and characterization of novel octa-arm star-block thermoplastic elastomers consisting of poly (p-chlorostyrene-b-isobutylene) arms radiating from a calix[8]arene core (1998)
    Springer
    Polymer bulletin 41 (1998), S. 167-174 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The synthesis and characterization of novel octa-arm star-blocks consisting of poly(p-chlorostyrene-b-isobutylene) (PpClSt-b-PIB) arms radiating from a calix[8]arene (C8) core are described. The synthesis was accomplished by living isobutylene (IB) polymerization induced by a novel octafunctional calix[8]arene derived initiator 1, followed by addition and living polymerization of p-chlorostyrene (pClSt). This sequential block copolymerization method allowed for precise molecular weight control of both polymeric blocks and thus gave rise to star-block thermoplastic elastomers (TPE) with an outstanding combination of mechanical and thermal properties, i.e., high tensile strengths (22 – 27 MPa) and elongations (∼500 %). Differential scanning calorimetry (DSC) indicated microphase separation into glassy PpClSt (Tg= 129°C) and rubbery PIB (Tg=−66°C) domains, and transmission electron microscopy (TEM) indicated that the PpClSt domains are dispersed in the PIB matrix.
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    Characterization of PET/LLDPE blends compatibilized with DEM-grafted-polyethylene (1998)
    Springer
    Polymer bulletin 41 (1998), S. 191-198 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Polyethylene terephtalate (PET)/linear low density polyethylene (LLDPE) blend compatibilized with diethylmaleate grafted polyethylene (DEM-g-LLDPE) were characterized by FTIR spectroscopy, thermogravimetrical analysis (TGA) and scanning electron microscopy (SEM). FTIR and TGA results indicate that there are interactions between the components of the blends, which produced variations in the infrared bands associated with the conformational changes (from gauche to trans) within the glycolic sequences of the polyester and a sinergistic effect on the thermal-oxidative stability of the compatibilized blends. Morphological analysis showed a dispersed particle size reduction and a better adhesion between the matrix and the disperse phase.
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    Viscometric detection of polymer inclusion complexes (1998)
    Springer
    Polymer bulletin 41 (1998), S. 215-221 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The reduced viscosity of poly(ethylene glycol) (PEG) is increased in solutions of (2-hydroxypropyl)-α-cyclodextrin (HPACD) significantly more than in the solution of (2-hydroxypropyl)-β-cyclodextrin (HPBCD) in agreement with the fact that a crystalline complex of PEG is formed in solutions of natural α-cyclodextrin but not in solutions of natural β-cyclodextrin. In analogy with that, the viscometry indicates formation of a complex between HPBCD with poly(vinyl alcohol) because the reduced viscosity is markedly increased in solutions of HPBCD but only slightly in solutions of HPACD. On the other hand, the increase in the viscosity of poly(N-vinylpyrrolidone) (PVP) was identical in HPACD and HPBCD solutions; therefore, the viscometry did not provide support for the suggested side-chain complexation between PVP and cyclodextrins.
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    Unperturbed molecular dimensions and the theta temperature of dextran in dimethylsulfoxide (DMSO) solutions (1998)
    Springer
    Polymer bulletin 41 (1998), S. 223-230 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The unperturbed molecular dimensions of dextran samples have been determined in dimethylsulfoxide (DMSO) solutions from intrinsic viscosity measurements at different temperatures. The unperturbed dimension parameter, Ko, has been calculated from extrapolation methods.The unperturbed root-mean-square end-to-end distance, 〈r2〉o 1/2, found for the polymer samples in DMSO solutions, indicate that the polymer coils are contracted. This distance varies from 3.25 × 10−7 cm to 2.94 × 10−7 cm for the sample T 40 and from 8.28 × 10−7 cm to 7.48 × 10−7 cm for the sample T 500, in the chosen solvent as the temperature is raised from 25°C to 45°C. In the system of dextran/DMSO, the long-range interaction parameter, B, was also determined and a significant decrease is observed between 25°–45°C. The theta temperatures, Θ, were obtained as Θ= 327.25 K, Θ= 327.41 K and Θ= 323.38 K from the temperature dependence of the interaction parameter in Kurata-Stockmayer-Fixman, Berry and Inagaki-Suzuki-Kurata equations, respectively.
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    Transcrystallization in syndiotactic polypropylene induced by high-modulus carbon fibers (1998)
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    Polymer bulletin 41 (1998), S. 239-245 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY It was first shown that transcrystallization can be induced in syndiotactic polypropylene (sPP) when a carbon fiber (CF) of high-modulus (HM) is embedded in the melt of sPP crystallizing under quiescent conditions. High-tenacity carbon fiber (HTCF), on the other hand, did not cause transcrystalline growth. Coating of HMCF by silicon carbide (SiC) stopped the transcrystallization of sPP. The difference in the morphology of the transcrystalline layer between isotactic PP (iPP) and sPP was revealed by phase contrast light (PCLM), scanning electron (SEM) and atomic force microscopy (AFM) taken from the etched surface of single fiber microcomposite specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050357
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  • 94
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    Electronic Resource
    Silica concentration dependence of the kinetics of polydimethylsiloxane adsorption on aggregates (1998)
    Springer
    Polymer bulletin 41 (1998), S. 253-260 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The kinetics of adsorption of pure polydimethylsiloxane or of bimodal mixtures, onto silica aggregates, was observed from the melt as a function both of polymer weight fraction (2.5 to 20 g/g) and of the specific area (50, 150 and 300 m2/g). Attention was focused on filled polymers wherein silica aggregates are connected to one another by adsorbed chains to form a network. Results were analysed according to a molecular approach. All observed kinetics curves were found to obey a property of superposition by using a suitable reduced time variable defined as : ; is the number average molecular weight and Qi is the initial amount of polymer per unit mass of silica. The rate of adsorption is proportional to 1/Qi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050359
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  • 95
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    Electronic Resource
    Synthesis of deuterobutadiene-butadiene AB2 and AB3 miktoarm star copolymers (1998)
    Springer
    Polymer bulletin 41 (1998), S. 283-289 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The synthesis of well-defined, monodisperse AB2 and AB3 miktoarm star copolymers, in which A is polydeuterobutadiene and B is polybutadiene, is described. The synthetic procedure involved reacting living polydeuterobutadiene with a large excess of either methyltrichlorosilane or tetrachlorosilane to yield a ‘one-arm star’. SEC traces of this ‘one-arm star’ are indistinguishable from that of the uncoupled polydeuterobutadiene indicating no further coupling to form multi-arm stars occurs. Unreacted chlorosilane was removed by distillation and the introduction of an excess of living polybutadiene generates the star. The star polymer was isolated from the precursor polybutadiene by fractionation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050364
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  • 96
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    Electronic Resource
    Synthesis and properties of thermotropic compounds with two terminal mesogenic units and a central spacer Homologous series of polymethylene -α, ω-bis[4-(4'-n-hexyloxybenzoyloxy)benzoate] (1998)
    Springer
    Polymer bulletin 41 (1998), S. 267-274 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: SUMMARY A new series of aromatic esters with two terminal mesogenic units and a central spacer 1 together with the free rodlike mesogenic ester unit 2,was synthesized and studied. The mesogenic properties of these compounds were investigated by differential scanning calorimetry, polarizing microscopy and X-ray diffraction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050362
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  • 97
    Electronic Resource
    Electronic Resource
    IR study of hydrogen bonding in novel liquid crystalline epoxy/DGEBA blends (1997)
    Springer
    Polymer bulletin 38 (1997), S. 439-445 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. The hydrogen bonding of LCE/DGEBA blend was studied using FT-IR. IR spectra of hydroxyl region and carbonyl region were investigated according to the content of LCE. IR spectra of LCE/DGEBA blend before and after curing were compared. Most hydroxyl group in DGEBA rich blends formed intermolecular or intramolecular hydrogen bonding after curing, while free hydroxyl group was present in LCE rich blends. Intramolecular hydrogen bonding was popular in DGEBA rich blends due to the conformational reason. Most carbonyl group was hydrogen bonded with hydroxyl or amine group after curing and the fraction of hydrogen bonded carbonyl was high in DGEBA rich blends.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050071
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  • 98
    Electronic Resource
    Electronic Resource
    A route to polysiloxanes with pendant imidazole groups Hydrosilylation of N-allylimidazole hydrochloride with methyldichlorosilane (1997)
    Springer
    Polymer bulletin 38 (1997), S. 371-378 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Hydrosilylation of N-allylimidazole hydrochloride by methyldichlorosilane (MeCl2SiH) under mild conditions leads to a high yield of N-[γ-(methyldichlorosilyl)propyl]imidazole hydrochloride – highly reactive monomer for synthesis of imidazole modified polysiloxanes. This compound was used as the substrate for the generation of new cyclooligosiloxanes with the imidazole group attached through the trimethylene bridge to a siloxane ring. The anionic ring-opening polymerization of these cyclics permits the controlled synthesis of polysiloxanes with imidazole groups pendant to the polymer chain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050062
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  • 99
    Electronic Resource
    Electronic Resource
    Novel aprotic polar polymers 1. Synthesis of aliphatic polysulfoxides (1997)
    Springer
    Polymer bulletin 38 (1997), S. 379-386 
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    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract. Aliphatic polysulfoxides having sulfoxide groups in the main chain were prepared by the selective oxidation of aliphatic polysulfides using aqueous hydrogen peroxide in chloroform. Degree of oxidation to sulfoxides was calculated from the integral ratios of methylene protons adjacent to sulfur atoms in 1H-NMR spectra. Poly(hexamethylene sulfoxide) was subjected to Swern oxidation of primary or secondary alcohols, in which 1-octanol and 6-undecanol were oxidized to give octanal and 6-undecanone, respectively, in quantitative yields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050063
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  • 100
    Electronic Resource
    Electronic Resource
    Polymerization of propynes bearing diphenylamino or indolyl groups (1998)
    Springer
    Polymer bulletin 41 (1998), S. 395-399 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Nitrogen-containing acetylenic monomers including 3-(N,N-diphenylamino)-1-propyne (DPAP), N-(2-propynyl)indole (PI), 2-methyl-N-(2-propynyl)indole (2-MePI) and 3-methyl-N-(2-propynyl)indole (3-MePI) polymerized in the presence of various transition metal catalysts. Poly(DPAP) was obtained with WCl6, MoCl5, Rh and Fe catalysts, and its weight-average molecular weights (M w) reached 140x103. Polymerization of PI and 2-MePI by Rh and Fe catalysts gave good yields of high molecular weight polymers with M w of 340x103 and 640x103, respectively. Polymerization of 3-MePI by WCl6- and MoCl5-based catalysts resulted in a soluble polymer (Mw= 52x103), whereas the use of Rh and Fe catalysts led to the formation of an insoluble polymer. All the polymers exhibited cutoff wavelengths around 450–500 nm, meaning the moderate to fair conjugation along the polymer backbones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002890050379
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