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  • 11
    Electronic Resource
    Electronic Resource
    Some light-scattering evidence of critical concentration in dilute polymer solution (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 32 (1958), S. 187-192 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Evidence of a critical concentration effect in dilute polymer solution has been obtained from light-scattering measurements in two ternary systems of the type polymer A-polymer B-solvent S. The root-mean-square end-to-end distance, (r2)1/2, of A was measured in a series of mixed solvents (B-S), differing from one another only in respect Of CB, the concentration of polymer B. The (r2)1/2 vs. CB curve exhibited a slight dip in the system polystyrene-polyvinyl acetate-benzene and a slight peak in the system polystyrene-polyvinyl acetate-butanone, at values of CB close to but not identical with the critical concentrations determined viscometrically for the same systems. The size, nature, and location of these light-scattering critical concentration effects are briefly discussed in the light of similar but better established viscosity effects.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1203212415
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  • 12
    Electronic Resource
    Electronic Resource
    A study of graft copolymers. II. Viscosity and light-scattering measurementsThis paper is based on a thesis submitted by J. A. Manson in partial fulfillment of the requirements for the degree of Doctor of Philosophy, September, 1956. Results of this investigation were reported at the 7th Canadian High Polymer Forum in Sarnia, Canada. November 9, 1956. (1958)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 33 (1958), S. 193-205 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of intrinsic viscosity and light scattering were made on fractions of polymers prepared by the redox polymerization of styrene in the presence of oxidized polystyrene or copolymers of skyrene and 4-vinylcyclohexene-1. For comparison, similar measurements were made on fractions of linear polystyrene. The conclusion that branching had taken place by graft polymerization was confirmed. Values found for the intrinsic viscosity, the molecular size, and the second virial coefficient were generally lower for fractions of the graft polymers than for fractions of linear polystyrene of the same molecular weight. It was also observed that fractionation of the graft polymers took place with respect to molecular size, not molecular weight, and that the most highly branched fractions were the most soluble. A comparison of experimental values of the branching ratio g with values calculated for a model having linear branches equally spaced along a backbone chain indicates that the graft polymers contain up to at least 6 branches per molecule. Values of Huggins' k′ for these branched molecules did not differ significantly from those for linear polystyrene (0.30 〈 k′ 〈 0.40). It is concluded that though k′ is sensitive to bushy branching, it is not measurably affected by the presence in the polymers of a few linear branches per molecule.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1958.1203312619
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  • 13
    Electronic Resource
    Electronic Resource
    Normal and cross-linked polystyrene. II. Viscosity behavior of polystyrene cross-linked in emulsion polymerizationThis paper is based on a thesis submitted by J. A. Manson in partial fulfillment of the requirements for the degree of Master of Science, April, 1951. Results of this investigation were reported at the Canadian High Polymer Forum in Ottawa, Canada, June 15, 1950. (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 9 (1952), S. 265-278 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By emulsion polymerization at 55°C., samples of styrene-divinylbenzene copolymer were prepared, whose content of divinylbenzene varied from 0 to 0.150%. Measurements of intrinsic viscosity and of the slope constants β and k′ were made, at 25.0°C. in butanone and in benzene, of these samples and of fractions obtained from them by fractional precipitation. In both solvents the intrinsic viscosity of unfractionated polymer was at a maximum at a divinylbenzene content of about 0.005% and k′ was at a maximum at about 0.10%. Since the gel point was also in the neighborhood of 0.10%, it is concluded that a maximum in k′ is a better indication of the gel point than a maximum in [η]. As with linear polymers, [η] was smaller and k′ larger in the poorer solvent. For the higher fractions of a given lightly cross-linked sample, k′ increased with increasing intrinsic viscosity, deviating progressively more from the value (0.40 in butanone) characteristic of the low fractions and of linear polystyrene. This progressive deviation appeared to begin at an intrisic viscosity which for different samples decreased with increasing proportion of divinylbenzene. These effects are accounted for qualitatively in termas of Baker's “microgel” concept and the effects of the two solvents on the dissolved molecules and dispersed microgel particles.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120090308
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  • 14
    Electronic Resource
    Electronic Resource
    Viscosity slope constant k' and its variation with molecular weight and temperature (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 9 (1952), S. 585-588 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120090617
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  • 15
    Electronic Resource
    Electronic Resource
    Viscometric evidence of critical concentration in dilute polymer solutionThis work was done as part of the requirements for the Ph.D. degree, and was supported by the National Research Council of Canada and the Research Council of Ontario. (1957)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 24 (1957), S. 429-437 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two viscometric methods have been developed for detecting the “critical concentration” (the concentration at which individual polymer molecules interfere with each other) of a dilute solution of a high polymer, B. In the first of these, the intrinsic viscosity, [η], of another polymer, A, is measured in a series of mixed solvents, each consisting of a solution of Polymer B in the solvent S, and each differing from the others only in the concentration of B (CB). For a number of polymer-polymer-solvent systems, data are presented which show that [η] is essentially independent of CB, except over a small range where its value changes fairly abruptly. This change marks the critical concentration. The second method is much faster but probably less reliable than the first. Nevertheless, the two gave values in good agreement. A method of calculating the critical concentration, based on the Flory-Fox theory of intrinsic viscosity, is described. Critical concentrations calculated for the several systems investigated agreed well with those obtained experimentally. The critical concentration was shown to be inversely proportional to the intrinsic viscosity of the Polymer B in experiments in which [η]B was varied by changing the molecular weight of the polymer and by changing the solvent. The effects observed are explained as resulting from interactions of the two polymer species in the solutions.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1957.1202410710
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  • 16
    Electronic Resource
    Electronic Resource
    Shear dependence of the reduced viscosity - concentration slope constant (1962)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 57 (1962), S. 209-225 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The variation with shear of the concentration dependence of the reduced viscosity was studied in the system polystyrene-toluene at 20, 40, and 60°C. The slope constant k′ was determined at constant shear stress k′T and at constant shear rate k′D; k′T was found to increase, k′D to decrease, with increasing shear. Alternatively, the concentration dependence was expressed in terms of Peterlin's effective viscosity. For this system the effective viscosity at constant shear stress was independent of shear but the effective viscosity at constant shear rate decreased with shear. The decrease in k′D, and in effective viscosity at constant shear rate with shear are attributed to molecular entanglement and an explanation is proposed for the observed differences in behaviour at constant shear stress and constant shear rate. In appendices a new formula for the calculation of viscosity ratios from the relative flow times is derived, and a procedure is outlined to compute intrinsic viscosities and limiting slope constants that will be free from absorption effects.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1962.1205716517
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  • 17
    Electronic Resource
    Electronic Resource
    Viscometric detection of branching in polymers. II. Branching in poly(butadiene-co-styrene) as a function of polymerization temperaturePaper presented at the Canadian High Polymer Forum, held as part of the Annual Conference of the Chemical Institute of Canada, in Montreal, June, 1952. The work, done as part of the requirements for the Master of Science degree, was supported by a grant from the National Research Council of Canada through its Associate Committee on Synthetic Rubber Research. (1953)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 10 (1953), S. 185-199 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Samples of poly(butadiene-co-styrene) - all of charge ratio butadiene:styrene 72:28 - were prepared in emulsion at 15, 30, 40, and 50°C. Essentially the same redox recipe was used for each, with slight modifications to produce in about the same time polymers of similar intrinsic vistex (1.9 to 2.0) at similar conversions (about 65%) well below the gel point. Each sample was fractionated by precipitation from 1% benzene solution with methanol, special pains being taken to obtain fractions of equal size (each around 5% of the original rubber in the sample fractionated). Careful measurements of the viscosity functions [η], β, and k′ for each fraction were made; with every sample except that prepared at the lowest temperature, the values of β and k′ were observed to deviate in the high molecular weight region from the “base value” common to lower fractions, the deviation starting at a lower molecular weight, and being greater at a given high molecular weight, the higher the temperature of polymerization. It is concluded that branching in a diene polymer of this type is repressed as the temperature of polymerization is decreased: the lower the temperature the higher is the molecular weight at which branching is detectable and the lower is the degree of branching at a given molecular weight. In the 15°C. rubber no branching was detectable at any molecular weight.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1953.120100206
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  • 18
    Electronic Resource
    Electronic Resource
    The viscosity behavior of linear and branched dextran sulfates (1962)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 57 (1962), S. 301-310 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Linear and branched samples of potassium dextran sulfate have been prepared without significant degradation from samples of linear and branched dextran having similar intrinsic viscosities. The dilute solution viscosity behavior of these polyelectrolytes has been studied with particular reference to the effect of branching and degree of sulfation. A comparison of the reduced viscosity - concentration curves, in aqueous 0.001N and 0.0005N KCl, of linear and branched potassium dextran sulfate with the same degree of sulfation revealed a significant difference in their viscosity behavior. This difference is attributed to a greater charge density in the nonlinear sample resulting from its branched structure.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1962.1205716523
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  • 19
    Electronic Resource
    Electronic Resource
    Semiquantitative aspect of short branch detection by using polyelectrolyte expansive effects (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 2527-2533 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Linear and branched dextran polyelectrolyte reduced viscosity-concentration curves, obtained by employing a solvent which contained a low concentration of simple electrolyte, were characterized by means of a set of relative expansion ratios, \documentclass{article}\pagestyle{empty}\begin{document}$ R_{nc_m } $\end {document} . The sets of \documentclass{article}\pagestyle{empty}\begin{document}$ R_{nc_m } $\end {document} for branched and linear dextran polyelectrolyte samples of identical degree of substitution, whose reduced viscosity-concentration curves were determined in the same solvent, did not differ. This is interpreted as indicating that the same expansive mechanism operated in the linear and branched polyelectrolyte systems when they were diluted. Plots of \documentclass{article}\pagestyle{empty}\begin{document}$ R_{nc_m } $\end {document} versus absolute concentration for linear and branched polyelectrolyte samples (of identical degrees of substitution, of different degrees of substitution and whose reduced viscosities were determined in solvents of different simple electrolyte concentrations) gave straight lines with a common intercept on the ordinate axis but with different slopes. It is suggested that the slope factor or p values of these lines might be employed as a means of detecting and measuring short branching in polymers convertible to polyelectrolytes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030710
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  • 20
    Electronic Resource
    Electronic Resource
    Viscosity behavior of branched and linear potassium carboxymethyl dextrans (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 1391-1399 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Samples of branched and linear dextran of near identical intrinsic viscosities have been carboxymethylated to varying degrees and converted to the potassium salts. The reduced viscosity-concentration curves of the branched and linear carboxymethyl dextran polyelectrolytes of identical degree of substitution in aqueous potassium chloride solutions (0.001N and 0.0005N) were compared. Significant differences were observed to exist. At low degrees of substitution (0.06-0.20 carboxymethyl group per anhydroglucose unit) the branched macroion possessed larger reduced viscosities than did its linear counterpart. At a higher degree of substitution (ca. 1.0 carboxymethyl group per anhydroglucose unit) the reduced viscosity curves of the branched and linear macroions crossed. These differences were shown to be independent of shear rate, molecular weight and molecular weight distribution. It is concluded that branching is responsible for the differences in the reduced viscosity-concentration behavior of the branched and linear potassium carboxymethyl dextran samples because of the higher charge density in the branched macroion.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030411
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