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  • 1
    Electronic Resource
    Electronic Resource
    Chemoenzymatic synthesis of linear poly(sucrose acrylate): Optimization of enzyme activity and polymerization conditions (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 3567-3578 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We have achieved significant improvements in the synthesis of poly(sucrose acrylate). A screen of 15 commercial enzymes was carried out and Alcalase 2T was selected as the best enzyme because of its high activity and selectivity for acylation of sucrose at only one site. The rate of the enzyme catalyzed acylation of sucrose to form sucrose 1'-acrylate was increased by a factor of ca. 100 compared to previous reports. This rate was increased 10-fold by treating the as received enzyme by adjusting the pH to the optimum value for the enzyme. An additional 10-fold increase was achieved by adding a lyoprotectant such as sucrose or poly(ethylene glycol) prior to lyophilizing the enzyme. Significantly higher molecular weights were obtained in aqueous polymerization systems than when N,N-dimethylformamide (DMF) was used as the solvent. Similarly, higher molecular weights were observed for oxidation/reduction than for azo-type free radical initiators. We have demonstrated that copolymers of sucrose acrylate and acrylic acid are readily prepared. Finally, by optimization of the polymerization system, we have increased the number-average molecular weight of the poly(sucrose acrylate) from M̄n = 54 000 to molecular weights M̄n as high as 2 400 000.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021951105
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  • 2
    Electronic Resource
    Electronic Resource
    Ring-opening metathesis polymerization of 7-phenylnorbornadiene and benzonorbornadiene (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 1031-1042 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ring-opened metathesis polymers of 7-phenylnorbornadiene and benzonorbornadiene have been prepared using a variety of catalysts based on Ru, Os, Ir, W and Mo chloride salts and complexes. Detailed 13C and 1H NMR spectra of these materials and their corresponding hydrogenated derivatives have been obtained and analysed for information concerning tacticities and fractions of cis double bonds (σc). The behaviour of 7-phenylnorbornadiene is similar to that of 7-methylnorbornadiene in that a strong preference for the anti over the syn mode of monomer insertion is observed in contrast to 7-tert-butoxynorbornadiene which shows little or no regioselectivity. Pronounced effect on σc are also observed using the OsCl3 catalyst as expected from previous experience of ring-opening metathesis polymerization (ROMP) systems containing chelating dienes and this catalyst. Weaker effects of this type due to complexation of monomer as a spectator ligand are also indicated for the polymerization of benzonorbornadiene; these are also compared to the effects of using Michael acceptor additives in metathesis systems.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021960406
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  • 3
    Electronic Resource
    Electronic Resource
    XPS O 1s binding energies for polymers containing hydroxyl, ether, ketone and ester groups (1991)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 17 (1991), S. 267-272 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: XPS spectra of nine model polymers containing oxygen functional groups are studied. The measured O 1s binding energies were 532.8 eV for ether and alcohol oxgens, 532.2 eV for ketone oxygens and 532.2 and 533.7 eV for the carbonyl- and ether-type oxygens in ester groups, respectively. Comparison with previous experimental and theoretical O 1s binding energies for these groups is also presented. Absolute O Is binding energies of polymers are not in agreement with those published by other groups. However, with the exception of ketone oxygens, binding energy shifts observed for the various functional groups are comparable.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740170508
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  • 4
    Electronic Resource
    Electronic Resource
    Solid state NMR study of the polymerisation of poly(ether sulphone) (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 33 (1994), S. 335-339 
    Details
    ISSN: 0959-8103
    Keywords: poly(ether sulphones) ; PES ; NMR ; CPMAS ; polymerisation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The synthesis of poly(ether sulphone) using the ‘carbonate’ route based on the reaction of 4,4′-dihydroxydiphenylsulphone, 4,4-dichlorodiphenylsulphone and potassium carbonate dispersed in diphenylsulphone has been studied by 13C CPMAS NMR spectroscopy. In the initial reaction the half potassium salt of 4,4′-dihydroxydiphenylsulphone is formed. No evidence for a stable full salt was found at any time during the polymerisation cycle and no appreciable oligomer formation took place before the polymerisation itself took place.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210330314
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  • 5
    Electronic Resource
    Electronic Resource
    Molecular weight distribution and rheological properties of polyisobutylene solutions (1971)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 1181-1194 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The molecular weight distribution of a series of polyisobutylenes was determined using osmotic pressure measurements, gel permeation chromatography, and intrinsic viscosity. All of the polymers except for one, a blend of the highest and lowest molecular weight constituents, had similar moderate molecular weight distributions. The “extended chain length” method of calibrating the gel permeation chromatograph for polyisobutylenes was found to be effective. Steady state and transient shear stresses and normal stresses were measured on 5% decalin solutions of these polymers. The zero shear viscosity increased with the 3.3 power of molecular weight, and the zero shear normal stress coefficient (σ11 - σ22)/Γ2 varied with the 7.5 power. Relative elastic memory as measured by (σ11 - σ22)/σ12 or stress relaxation increased with increasing molecular weight (and at constant number- or weight-average molecular weight) with breadth of distribution. Stress overshoot also correlated with this tendency.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1971.070150513
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  • 6
    Electronic Resource
    Electronic Resource
    Gel permeation and thin-layer chromatographic characterization and solution properties of butadiene and styrene homopolymers and copolymers (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 2811-2827 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Gel permeation chromatographic (GPC) and thin-layer chromatographic (TLC) studies of polystyrene, polybutadienes (BR), and their copolymers (SBR) have been carried out. GPC primarily separates them on the basis of molecular size, and TLC, on the basis of composition. Methods of obtaining absolute molecular weight distributions for BR and SBR based upon variations of the Strasbourg Universal Calibration procedure are described. In particular, [η]-M relationships in both the GPC solvent (THF) and in a second solvent (toluene) were used; in addition, results of statistical mechanical calculations for \documentclass{article}\pagestyle{empty}\begin{document}$\overline {s^2 }$\end{document} (based on the assumption of negligible steric hindrance and freely rotating bonds) were applied. An experimental comparison of these methods was carried out, and use of the [η]-M relationships for both solvents was found to give satisfactory results. The predictions of the statistical theory were too low. A detailed study of polymer-solvent-gel interaction in the GPC unit was made through investigation of ternary phase equilibrium in the (polystyrene)-THF-(polymer) system. The polymers studied included BR and SBR with varying styrene contents. Experimental techniques for TLC separations of BR, SBR, and polystyrene according to the composition are described.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070161108
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  • 7
    Electronic Resource
    Electronic Resource
    The polymerisation of ethylene with high activity magnesium reduced titanium trichloride catalysts in the absence of hydrogen (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 3461-3473 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Polymerisation von Äthylen unter Verwendung eines mit Magnesium reduzierten Titantrichlorid-Katalysators, zusammen mit gewöhnlichen Aluminiumalkyl-Aktivatoren, wird beschrieben. Die bereits berichtete hohe Aktivität dieses Katalysatortyps wird bestätigt. Bei 50°C und 1 Atm. (1,01325 bar) Druck wird ein Wert für die Aktivitätskonstante von 3,4.106 g dm3 (mol TiCl3)-1 h-1 erhalten. Dieser Wert ist ungefähr 102 mal höher als derjenige eines auf übliche Weise mit Aluminium reduzierten Titantrichlorids. Die Viskosotäts-Molekulargewichts-Zeit (oder Umsatz)-Beziehungen sind nicht sehr verschieden von denen, die mit den üblichen Katalysatoren erhalten werden. Die Analyse der Resultate weist darauf hin, daß ein großer Teil (z. B. 50%) der Titan-Atome im Titantrichlorid, das mit Magnesium reduziert wurde, als aktive Zentren fungieren.
    Notes: The polymerisation of ethylene using magnesium reduced titanium trichloride catalysts, together with the usual aluminium alkyl activators is described. The previously reported high activity of this type of catalyst was confirmed. At 50°C and 1 atm. (1,01325 bar) pressure a value of 3,4.106 g dm3 (mol TiCl3)-1h-1 was obtained for the activity constant, a value about 102 times larger than for a conventional aluminium reduced TiCl3. On the other hand the viscosity-molecular weight-time (or conversion) relations are not very different from those given by conventional catalysts. Analysis of the results suggests that a high proportion (e.g. 50%) of the titanium atoms in the magnesium reduced TiCl3 functions as active sites.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021751212
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  • 8
    Electronic Resource
    Electronic Resource
    Emulsion polymerization of butyl acrylate: Spin trapping and EPR study (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 3031-3037 
    Details
    ISSN: 0887-624X
    Keywords: emulsion polymerization ; butyl acrylate ; poly(n-butyl acrylate) ; Electron Paramagnetic Resonance ; spin trapping ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The propagating radical in the emulsion polymerization reaction of butyl acrylate was detected by Electron Paramagnetic Resonance (EPR) spectroscopy using two spin-trapping agents, 2-methyl-2-nitrosopropane (MNP) and α-(4-pyridyl 1-oxide)-N-tert-butylnitrone (PyOBN). Through analysis of hyperfine structure of the spectra obtainedfrom the trapped radicals, the propagating radical is inferred to be the well known acrylate radical, — [CH2—CH(COOC4H9)]n—CH2—CH(COOC4H9)—. © 1994 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321604
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  • 9
    Electronic Resource
    Electronic Resource
    Sucrose diacrylate: A unique chemically and biologically degradable crosslinker for polymeric hydrogels (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2221-2229 
    Details
    ISSN: 0887-624X
    Keywords: biodegradation ; hydrogels ; crosslinking agent ; sucrose diacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of degradable hydrogels based on different vinyl monomers such as acrylamide, sucrose-1′-acrylate, and acrylic acid were synthesized using sucrose-6,1′-diacrylate (SDA) as a crosslinking agent. SDA was prepared by enzymatic transesterification of vinyl acrylate with sucrose in pyridine. Base catalyzed hydrolysis of SDA in aqueous solution was studied as a function of pH. As expected, hydrolysis of SDA was faster at higher pHs such that poly(acrylamide), poly(sucrose 1′-acrylate), and poly(acrylic acid) hydrogels underwent substantial degradation at and above pH 7, 9, and 13, respectively. The degradation was characterized by changes in the swelling ratios of the hydrogels indicating breakage of the crosslinking agent. Degradation of the hydrogels at their chemically stable pHs was studied in presence of enzymes. Enzymes, including pepsin and a fungal Lipase, were able to degrade the poly(acrylamide) hydrogel at pH 4 and 5, respectively. Poly(acrylic acid) hydrogel was degraded in presence of a fungal protease at pH 7.8. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2221-2229, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New polar silane-PEO polyester complexes as polymer electrolytes (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1093-1106 
    Details
    ISSN: 0887-624X
    Keywords: ion-conducting polymers ; silicon ; synthesis ; stability ; conductivity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trifunctional carbosilanes containing hydroxy and cyano groups have been synthesized in good yields and incorporated into polyether-based electrolytes. The new linear and cross-linked modified PEOs have been characterized by DSC and conductivity measurements. The effect of silane content, the length of the PEO block, glycerol concentration, and temperature on glass transition temperature and conductivity of lithium salts complexes of these materials has been evaluated. The new materials showed improved conductivity (∼ 10-5 S cm-1) at ambient temperatures compared with unmodified polyethers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1093-1106, 1998
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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