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  • 1
    Electronic Resource
    Electronic Resource
    Microfiber formation: Immiscible polymer blends involving thermoplastic poly(vinyl alcohol) as an extractable matrix (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 1837-1846 
    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 utilization of polymer-blend technology to prepare microfibers via extraction of one of the components is known technology. Achieving fibrillation (microfiber formation) is not an a priori consequence of polymer blends exposed to a shear or elongational flow field. The viscosity ratio, concentration ratio, interfacial tension, and second normal stress function have all been noted to be important factors in achieving fibrillation in polymer blends. It has been found that thermoplastic poly(vinyl alcohol) is particularly effective in this technology, yielding fibrillated systems that can be easily extracted to yield microfibers (0.1-5 μ diameter). Thermoplastic poly(vinyl alcohol) (PVOH) offers cold-water solubility, biodegradability, and fibrillation characteristics with many commodity polymers (polyolefins, polystyrene, scrap mixtures), thus offering advantages over previously investigated extractable polymers. In addition, the resultant microfibers via this process can be pulped and handled in paper-making processes. The process for microfiber formation, the process variables, the polymers applicable to the formation of microfibers using PVOH as an extractable matrix, and the properties of the resultant microfibers are discussed with emphasis on the characterization of the microfibers as a fibrous thixotrope additive. Potential utility of the microfibers via this process include polymeric paper and admixtures with cellulosic-based pulp, oil- or water-adsorbent mats, fibrous thixotrope additives, filters, filler rentention and pitch control in paper applications, and ultralow denier fibers. © 1994 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070521301
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  • 2
    Electronic Resource
    Electronic Resource
    Crystallization kinetics of poly-ε-caprolactone from poly-ε-caprolactone/poly(vinyl chloride) solutions (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 3607-3617 
    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 polymer-polymer solution of poly(vinyl chloride) and poly-ε-caprolactone yields an excellent system for studying the crystallization kinetics of a crystallizable component from a polymer-polymer solution. Unlike previous studies of isotactic-atactic polystyrene solutions for which the glass transition temperature is invariant with composition, this system exhibits a marked dependence of Tg on the composition. The experimental data dE⅓(modulus)/dt (psi⅓/min) were obtained over a composition range of 40 to 70 wt-% poly-ε-caprolactone. With the appropriate modification of the spherulitic growth rate equation, the expression \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{dE^{{1 \mathord{\left/{\vphantom {1 3}} \right.\kern-\nulldelimiterspace} 3}}}{dt}=k'\left( {1 - C_d } \right)_e \frac{-\Delta F_{WLF}}{RT},\left( \Delta F_{WLF}=\frac{4120T}{51.6+T-T_g}\right)$\end{document} approximated a reasonable fit of the experimental data. This demonstrates a marked dependence of the crystallization rate on concentration. Secondary observations of this investigation show a slower crystallization rate for high molecular weight poly-ε-caprolactone and a slow secondary crystallization step. Both homopolymer poly-ε-caprolactone and poly-ε-caprolactone in the poly-ε-caprolactone/poly(vinyl chloride) solution show a slow (relative to the nucleation-controlled step) crystallization stage considered to involve a slow diffusion mechanism.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070171205
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  • 3
    Electronic Resource
    Electronic Resource
    Permeation of ethane-butane mixtures through polyethylene (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2083-2095 
    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: Permeation of ethane-butane mixtures a t atmospheric pressure through polyethylene was investigated in the temperature interval of 30-60°C. The integral permeation constant P̄ and the integral diffusion coefficient D̄ of both ethane and butane were satisfactorily correlated by using an exponential and also a linear function of butane concentration. This was attributed to the plasticizing of the film by butane, whose solubility constant is approximately ten times that of ethane in the temperature interval investigated. The separation factor Gi, j defined as the ratio of the permeation constant of butane to the permeation constant of ethane over the range of mixture compositions and temperatures investigated, remained nearly constant at values in the range of 2.8-3.2. The insignificant change in Gi, j is due to the proximity of the activation energies of permeation of ethane and butane (10.95 and 10.75 kcal/mol, respectively) and the similar magnitude of change in the permeation constants with increasing butane concentration. Experiments were run in which the film was initially in equilibrium with the same partial pressure of butane as in the mixture to be studied. It can be shown that the diffusion coefficient of ethane in this case is related to the following function of film position: D = D(o)(β0 + β1x)δ. The time lag of diffusion of ethane in these experiments decreased with inrreasing butane concentration.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120911
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  • 4
    Electronic Resource
    Electronic Resource
    The desorption of ethane-butane mixtures from polyethyleneProd. No. 1611 (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2007-2019 
    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 desorption of mixtures of ethane and butane at atmospheric pressure from low-density polyethylene was investigated over the temperature range from 20 to 60°C. Desorbed penetrants were continuously trapped in glass tubes immersed in liquid nitrogen, and composition was determined as a function of time by means of gas chromatography. The ratio of the quantity of desorbed gas at any time t, qt, to the quantity at complete desorption, q∞, was used to determine diffusion coefficients and solubility constants. The diffusion coefficients for both ethane and butane increase with increasing butane concentration in the temperature interval investigated. The solubility of both penetrants can be correlated by Henry's law at 40, 50, and 60°C. However, at 20 and 30°C. the solubility constant for both penetrants increases with increasing butane concentration. This trend is consistent with experimental observations for single-component diffusion and solubility of several hydrocarbons in polyethylene, where increasing concentration of penetrant plasticizes the polymer, resulting in increasing diffusion coefficients and solubility constants.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111017
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  • 5
    Electronic Resource
    Electronic Resource
    Physical property characteristics of polysulfone/poly-(dimethylsiloxane) block copolymers (1973)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 29 (1973), S. 47-62 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Eine Reihe von Polysulfon-Polydimethylsiloxan-(AB)n-Blockcopolymeren wurde über eine breite Zusammensetzungsweite durch Variation des Molekulargewichtes der Polysulfon- und Polydimethylsiloxan-Blöcke dargestellt. Die Eigenschaften dieser Polymeren reichen von einem harten Stoff bei hohem Polysulfongehalt (〉65% Polysulfon) bis zu einem elastischen Stoff bei hohem Gehalt an Polydimethylsiloxan (〉65% Polydimethylsiloxan).Es wird gezeigt, daß eine einfache Erweiterung der MAXWELL-Analyse von heterogenen Systemen genügt, um Permeabilitätsdaten vorherzusagen. Eine ähnliche Handhabung der KERNER-Analyse kann angewandt werden, um die Moduli vorherzusagen. Die Analyse der Permeabilitäts-Ergebnisse und der Moduli-Ergebnisse zeigt das Auftreten der Phasenumkehrung bei ähnlicher Zusammensetzung dieser Zweiphasen-Blockcopolymeren an.Von einem gegebenen Blockcopolymeren können verschiedene physikalische Eigenschaften erhalten werden, wenn Polymerfilme aus verschiedenen Lösungsmitteln hergestellt werden, oder wenn der Polymerfilm mit einem Lösungsmittel für nur eine Phase des Polymeren angequollen wird. Die Neigung der Polydime-thylsiloxan-Komponente zu kristallisieren, hiingt von der Flexibilitiit des Copoly-meren ab. Die Flexibilitiit kann bei der Herstellung des Filmes eingestellt werden.
    Notes: A series of polysulfone/poly(dimethylsiloxane) (AB)n block copolymers have been synthesized over a wide composition range by varying the molecular weights of the polysulfone and poly(dimethylsiloxane) blocks. The properties vary from a rigid material at high polysulfone content (〉65% polysulfone) to an elastomeric material at high poly(dimethylsiloxane) content (〉65% poly(dimethylsiloxane)).A simple extension of MAXWELL's analysis of heterogeneous systems is shown to be applicable to the prediction of permeability data and a similar treatment of KERNER's analysis can be used for predicting modulus data. Analysis of both the permeability data and modulus data predict a similar phase inversion composition for this two-phase block copolymer.Different properties can be obtained with a given block copolymer composition by casting films from different solvents or by swelling the films in a non-solvent which preferentially swells one phase only. The tendency of poly(dimethylsiloxane) to crystallize at low temperature is dependent upon the flexibility of the block copolymer, which can be influenced by the method of film preparation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1973.050290103
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  • 6
    Electronic Resource
    Electronic Resource
    Isomorphic behavior of poly(aryl ether ketone) blends (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 25 (1987), S. 311-323 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Blends of various poly(aryl ether ketones) have been found to exhibit a range of miscibility and isomorphic behavior. This range is dependent on molecular weight; however, for poly(aryl ether ketones) with number-average molecular weight of 20,000, this range is about ±25% difference in ketone content. All miscible blends exhibit isomorphism, and all immiscible blends exhibit no evidence of isomorphism. The dependence of the glass transition temperature Tg versus composition exhibits a minimum deviation from linearity whereas the melting temperature Tm versus composition exhibits a pronounced maximum deviation from linear behavior.The crystalline melting point versus composition for isomorphic blends is considerably different than for random copolymers with isomorphic units. Homopolymers and random copolymers exhibit a melting point that is a linear function of ketone content (increasing ketone content increases Tm). For blends, the melting point is essentially the same as that of the higher melting constituent until high levels of the lower melting constituent are present. The observed melting point versus composition behavior will be interpreted using classical theory to calculate the components of the liquid and crystalline phase compositions. As a miscible blend is cooled from the melt, essentially pure component of the highest melting point crystallizes out of solution, as predicted by calculated solid-liquid phase diagrams. This occurs until the crystallization is complete owing to spherulitic impingement. At high concentrations of the lower melting constituent, lower melting points will be observed because the highest melting constituent will be depleted before the crystallization is complete.In many miscible blends involving addition of an amorphous polymer to a crystalline polymer, the degree of crystallinity of the crystalline polymer has been shown to increase. On the basis of evidence presented here, it is hypothesized that dilution by a miscible, amorphous polymer allows for a higher level of crystallinity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1987.090250205
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