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  • 1
    Electronic Resource
    Electronic Resource
    Photochemically induced oxidative surface modification of polyimide films (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 83-89 
    Details
    ISSN: 0887-624X
    Keywords: polyimides ; photooxidation ; surface modification ; gas separations ; ultraviolet irradiation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyimide membranes that contain both the phthalimide chromophore and abstractable hydrogens undergo photochemically-induced oxidative surface modification when they are irradiated with ultraviolet (UV) light for 0.5-30 min in air. The reaction requires 200-300 nm light and the presence of oxygen, and the surface-modified membranes show much higher oxygen/nitrogen selectivities than the untreated films. A mechanism for the photochemical reaction that is based on the photochemistry of structurally-similar monomeric phthalimides is proposed. The observed selectivity increases can also be explained by this mechanism. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310110
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of diamine monomer structure on the gas permeability of polyimides. I. Bridged diamines (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 909-921 
    Details
    ISSN: 0887-624X
    Keywords: polyimides ; gas separation membranes ; permeability ; ortho-substituted aromatic diamines ; oxygen/nitrogen separation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Permeability measurements for oxygen and nitrogen were carried out on a series of structurally similar polyimides in order to define structure/permeability relationships. The polyimides were prepared from 5,5′-[2,2,2-trifluoro-1-(trifluoromethyl) ethylidene] bis-1,3-isobenzofuranedione (6FDA) and a variety of substituted methylene dianilines and benzidines. A correlation between the diamine monomer structure and polymer permeability was found, particularly with diamine monomer variations at the ortho positions of the diamine relative to the amino moiety. These correlations were semilogarithmic, relative to the summation of the substituent volumes. Direct correlations were observed between the measured properties of polymer density and interchain d-spacings and the oxygen permeability value of each of these polyimides. In addition, we observed that the calculated values of fractional free volume were related to oxygen permeability in a manner which enabled us to identity a polar component in the effects of these ortho substituents. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310409
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  • 3
    Electronic Resource
    Electronic Resource
    Critical surface tension of blends of thermosetting fluorochemical methacrylate polymers with thermosetting hydrocarbon acrylate polymers (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 2235-2242 
    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: Critical surface tensions (γc) for blends of thermosetting fluorochemical methacrylates and thermosetting acrylate polymers are measured in their cured thermoset condition. Values of γc depend on (1) the nature of the fluorochemical side chain and (2) the ratio of fluorochemical containing polymer to hydrocarbon polymer. The minimum value for γc is found to occur at a fluorocarbon to hydrocarbon polymer ratio of 0.10 to 0.001. At higher and lower ratios (〉0.1 and 〈0.001), the value for γc increased. Thus, certain blends of fluorochemical methacrylate copolymer with hydrocarbon acrylate copolymer give lower γc than either the hydrocarbon acrylate or the fluorochemical methacrylate copolymer.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190815
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  • 4
    Electronic Resource
    Electronic Resource
    Properties of vinyl chloride-propylene copolymers prepared by incremental feed and batch feed procedures (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 1057-1071 
    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: A procedure is described for preparation of uniform-composition copolymers of vinyl chloride-propylene, polymers whose composition does not vary as a function of polymer conversion. Inherent viscosity (IV) and melt flow (MF) properties of these resins were determined. These were related to the propylene content (%PB) of the polymer. A linear relationship was found for IV versus %PB and log MF versus %PB. Variation in copolymer composition as a function of conversion for batch-copolymerized vinyl chloride-propylene (VCM-P) system were calculated using established reactivity ratios. These values of %PB at different conversions were used to predict the MF and IV values for batch-copolymerized VCM-P systems at different conversions. Experimental verification of these predictive values were made. Close agreement was found for predicted and experimentally determined MF values at different conversions. Unusual effects were observed between the predictive and experimentally determined IV values at different conversions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210420
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  • 5
    Electronic Resource
    Electronic Resource
    Physical properties of vinyl chloride-propylene copolymers (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 2361-2376 
    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 polymerization conditions that control the physical properties of vinyl chloride-propylene copolymers have been examined, and the interaction between these polymerization conditions and the melt rheology, intrinsic viscosity, and bound propylene level of the copolymer have been quantified into a series of process control relationships. The interaction between primary and secondary suspension systems have been optimized for these copolymers to maximize the resin porosity. Binary initiator systems have been identified to overcome the degradative polymer kinetics associated with propylene comonomer.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310733
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  • 6
    Electronic Resource
    Electronic Resource
    Polymerization of vinyl chloride in presence of substituted olefins: Effects on molecular weight and melt rheology (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 867-876 
    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: Vinyl chloride (VCM) was polymerized by free-radical suspension procedures in presence of methyl-substituted olefins such as propylene, isobutylene, cis-2-butene, trimethylethylene, and tetramethylethylene. Dilute solution viscosities of polymer formed in the presence of these olefins were measured and compared to that of trichloroethylene, a chlorinated chain-transfer agent. A pseudo-chain-transfer coefficient for these olefins was calculated based on solution viscosity determinations and found to be exponentially proportional to the number of allylic hydrogens. The effects on melt flow of the olefin distribution in the polymer chain were examined. Olefins at the ends of polymer chains were found to have no effect on melt rheology, whereas those in internal portions of chains were found to significantly increase melt flow.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070230321
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  • 7
    Electronic Resource
    Electronic Resource
    Vinyl chloride-vinyl acetate kinetic modeling. I. Determination of radical efficiency factor (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 3377-3384 
    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: Using dead end polymerization procedures, the copolymerization of vinylchloride-vinyl acetate was studied in laboratory scale reactors. Predictive kinetic models based on modified Hamielec equations were developed which were valid up to the limit of the experiments, 35% conversion. The efficiency factor (f) for the t-butylperneodecanoate initiator was determined for a range of initiator concentrations in a comonomer mixture.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300820
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of polymerization conditions on the melt rheological properties of vinyl chloride-vinyl acetate copolymers (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 1285-1308 
    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: Mathematical models have been developed which predict the composition, molecular weight, and melt rheological properties for vinyl chloride/vinyl acetate copolymers of inherent viscosity range 0.4-0.7 dL/g and bound vinyl acetate levels of 3.8-17.4%. The effect of polymer long chain branching on the viscous/elastic moduli ratio is discussed as well as the comparison of Tinius-Olsen melt index measurements vs. mechanical spectrometer results. The reactivity ratio for vinyl chloride/vinyl acetate comonomer pairs was remeasured and found to be significantly different from literature values.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300332
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  • 9
    Electronic Resource
    Electronic Resource
    Particle structure of PVC based on cellulosic suspension system. III. Effect of monomer refluxing (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 1365-1378 
    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 effects of monomer refluxing on both resin properties and reactor fouling of suspension PVC have been studied in a laboratory-scale 14-L reactor. Process control equations were developed which related the particle properties to the reflux condenser operation by controlling the parameters of (1) the time at which refluxing is begun and (2) the rate profile of heat removal from the condenser. An operating envelope has been developed for laboratory scale operations which optimizes the cycle time of polymerization while minimizing the adverse effects on particle properties. These operating conditions may have application to production scale operations when the proper scaling factors are employed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300404
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  • 10
    Electronic Resource
    Electronic Resource
    Conformational aspects of polypeptides. XVII. Synthesis of oligomers and co-oligomers derived from L-alanine and L-glutamic acidFor previous papers in this series see Goodman and Rosen. (1966)
    New York : Wiley-Blackwell
    Biopolymers 4 (1966), S. 275-303 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of oligomers was synthesized of the form: \documentclass{article}\pagestyle{empty}\begin{document}$${\rm Z} \rlap{--} ({\rm Ala} \rlap{--})_n {\rm OEt}$$\end{document} Where Z is the benzyloxycarbonyl group and n = 2, 3, 5, 10. We encountered difficulty in dissolving the decamer in any solvent except strong organic acids. We therefore prepared co-oligomers of the type: where (a) w = x = y = 1; (b) w = 0, x = y = 3; and (c) w = x = y = 3. A series of model compounds composed of glycine L-alamine and γ-methyl-L-glutamate were also prepared. We converted manyof the benzyloxycarbonyl oligopeptides into their corresponding acetyl derivatives. Some of these peptides were synthesized by mixed anhydride and active ester techniques while others were prepared via azide coupling techniques using the tert-butoxycarbonylhydrazide blocking group. All reactions proceeded with retention of configuration.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1966.360040304
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