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  • 1
    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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  • 2
    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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  • 3
    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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  • 4
    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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  • 5
    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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  • 6
    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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  • 7
    Electronic Resource
    Electronic Resource
    Use of different fluorochromes for monitoring protein elution and transfer (1987)
    Weinheim : Wiley-Blackwell
    Electrophoresis 8 (1987), S. 25-28 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Protein molecular weight standards labeled with different fluorochromes were tested for their usefulness in following the protein transfer from sodium dodecyl sulfate-polyacrylamide gels to nitrocellulose and for electro-elution of proteins from polyacrylamide gels. Dichlorotriazynylaminofluorescein labeled proteins appear to be useful for both purposes as they are stable, their detection sensitivity was high (about 10 ng of protein on nitrocellulose) and the coupling of the fluorochrome did not appreciably change the molecular weight of any protein examined. On the other hand, proteins labeled with tetramethylrhodamine isothiocyanate, or its heterocyclic derivative, were of limited usefulness as standards. Labeled proteins of molecular weight below 20 kDa formed diffuse bands on gels. Therefore, these particular fluorescent protein standards appear to be useful in following the elution from gels, or as references on nitrocellulose, only for proteins larger than 20-25 kDa.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150080106
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  • 8
    Electronic Resource
    Electronic Resource
    A model for the mobility of single-stranded DNA in capillary gel electrophoresis (1993)
    Weinheim : Wiley-Blackwell
    Electrophoresis 14 (1993), S. 492-501 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The electrophoretic mobility of single-stranded DNA in denaturing polyacrylamide gel-filled capillaries is analyzed as a function of the applied electric field. The resultant mobility plots are complex functions of the fragment size and electric field. Traditionally, these plots are separated into three mobility regimes corresponding to Ogston sieving, reptation without stretching and reptation with stretching theories. However, none of these theories accurately models the variations in mobility that we observe with electric field strength. As a result, we propose a modification of the Ogston sieving theory which accounts for the stretching of migrating DNA molecules in the direction of the electric field. This theory assumes that the applied electric field in conjunction with the gel matrix distorts the DNA, altering the effective size of the migrating molecule. The stretched DNA offers a smaller cross-section to the gel pore and thus sieves as though it were a smaller molecule. In this modified Ogston theory, the electrophoretic mobility depends only on the applied electric field, the size of the fragment, and constants which are independent of size and field strength. The modified Ogston equation accurately predicts the mobilities of DNA fragments in all three mobility regimes9 providing a single, simple model to account for all of the observed behavior.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150140176
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  • 9
    Electronic Resource
    Electronic Resource
    Separating field strength, temperature, and pulsing effects in pulsed field electrophoresis (1994)
    Weinheim : Wiley-Blackwell
    Electrophoresis 15 (1994), S. 1084-1090 
    Details
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The utility of pulsed field electrophoresis for DNA sequencing is investigated. Previous studies have indicated a beneficial retardation of sequencing fragments when pulsed fields are employed. The interpretation of these results is complicated, however, by concomitant variations in electric field strength and/or temperature. Methods are presented here permitting discrimination of such mobility effects due to pulsing, field strength, and temperature. It is demonstrated that under the conditions employed here, observed mobility effects are due to electric field variations rather than pulsing. These conditions thus correspond to the low frequency/small molecule limit. The effect of temperature is estimated from the steady state solution to the heat conduction equation under appropriate boundary conditions. No temperature effect upon mobility is operative in the thin gel system employed, due to the high efficiency of heat transfer. However, it is shown that in conventional gel systems large temperature-related mobility effects can occur. These methods for dissecting and understanding mobility effects in pulsed field electrophoresis are expected to be of general utility.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.11501501162
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  • 10
    Electronic Resource
    Electronic Resource
    Automatic matrix determination in four dye fluorescence-based DNA sequencing (1996)
    Weinheim : Wiley-Blackwell
    Electrophoresis 17 (1996), S. 1143-1150 
    Details
    ISSN: 0173-0835
    Keywords: DNA sequencing ; Matrix ; Algorithm ; Multicomponent analysis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The four dye fluorescence detection strategy is a widely used approach to automated DNA sequence analysis. An important aspect of data processing in this approach is the multicomponent analysis to deduce the concentrations of four fluorophores from fluorescence emission intensities at four different wave-lengths. This requires knowledge of the correct transformation matrix M. The matrix M is a function both of the fluorophores employed and the fluorescence detection system. M is typically determined either by a calibration process with individual dyes, or by choosing four well-separated individual peaks corresponding to the four different dyes. Both are time-consuming and complicated procedures for routine use. An automatic scheme for finding M directly from raw sequence data is presented here. This facilitates data analysis and the underlying algorithm may also find utility in other multispectral applications.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elps.1150170626
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