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  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 431-436 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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  • 2
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Partial molar excess free enthalpies (or excess chemical potentials) at infinite dilution were obtained over a large temperature range by gas chromatography. Data on n-alkenes in Apiezon M are interpreted by the Prigogine-Patterson theory; data on normal and branched alkanes in squalane and polydimethylsiloxane (PDMS) are discussed in terms of the Prigogine-Patterson theory and the solution theory of Flory, Orwoll, and Vrij. For the alkane-PDMS systems heats of dilution and partial excess heat capacity data are given.The aim of this work is to get some insight in the applicability of these solution theories to mixtures of fluids, the properties of which may slightly violate the basic assumptions of these theories. It is shown that orientational order in and a large cross-sectional chain diameter of the polymer solvent do not affect their applicability to the partical molar excess free enthalpies of apolar mixtures, whereas large dissimilarities between the force fields around the segments of the mixture components and/or dissimilar chain flexibilities detract from the applicability of these theories (alkanes in PDMS).Special attention has been paid to the effects of dissimilar size and shape of the segments of the mixture compounds on the magnitude of the interchange interaction parameter. It is shown that the multiple-connected segment model after Lichtenthaler et al. does not warrant a reliable combinatorial contribution. Comparison of the interaction parameters obtained for n-alkanes in n-alkanes, Apiezon, squalane, and polyisobutylene and for branched alkanes in squalane reveals that the magnitude of this parameter is affected by small end-effects due to the relative weakness of methyl-methylene interactions.
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 437-441 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 579-597 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanical properties of crosslinked SBR containing varying amounts of a glass bead filler have been studied. It is shown that the stress-strain response at a given test rate and temperature can be rationalized provided dewetting around the glass bead filler is taken into account. Direct measurements of the volume dilatation as a function of both strain and filler content have been obtained. This information in conjunction with the model proposed herein has been used to satisfactorily reproduce the stress-strain curves to strains up to about 200%. It is also shown that at the break point complete dewetting has occurred so that the rupture properties of the filled are the same as that of the unfilled gum. This was found to be true for all temperatures and rates studied.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 599-605 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 663-666 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 675-682 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the preceding paper, general equations were established for the motions of chains confined to a tetrahedral lattice. In the present paper, bond orientation correlation and autocorrelation functions are explicitly calculated for the case where only three-bond elementary motions are considered. Effects due to the chain end are analyzed and the relaxation time distribution function is established. The expressions obtained reflect the influence of the chain structure. Finally, to characterize the dynamic behavior of chains in orientation relaxation experiments, the notion of an independent kinetic segment is proposed.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 683-702 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The elastic free energy for a tetrafunctional network is here expressed as \documentclass{article}\pagestyle{empty}\begin{document}$$ G_{{\rm el}} = C_1 \left( {\lambda _1 ^2 + \lambda _2 ^2 + \lambda _3 ^2 - 3} \right) + C_2 \left[ {\left( {\lambda _1 \lambda _2 \lambda _3 } \right)^m \left( {\lambda _1 ^{ - 2} + \lambda _2 ^{ - 2} + \lambda _3 ^{ - 2} } \right) - 3} \right] - \left( {{{C_1 } \mathord{\left/ {\vphantom {{C_1 } {C_2 }}} \right. \kern-\nulldelimiterspace} {C_2 }}} \right){\rm }\ln {\rm }\left( {\lambda _1 \lambda _2 \lambda _3 } \right) $$\end{document} where λ1, etc., are the principal extension ratios relative to the state of reference (wherein 〈r2〉 = 〈r2〉0), and C1, C2, and m are arbitrary parameters. The free energy of a swollen system is taken to be the sum G = Gmix + Gel of Gel and the free energy of mixing \documentclass{article}\pagestyle{empty}\begin{document}$ G_{{\rm mix}} = RT\left[ {n_1 \ln v_1 + n_2 \ln v_2 + \bar \chi n_1 v_2 } \right] $\end{document}. Stress-strain relations and the chemical potential μ1 are derived from G as functions of the elasticity parameters C1, C2, and m, and of the thermodynamic interaction parameter χ or of \documentclass{article}\pagestyle{empty}\begin{document}$\chi = \bar \chi + n_1 v_2^{ - 1} \partial \bar \chi /\partial n_1 $\end{document}. The dilation of the semi-open system subject to deformation when exposed to diluent at fixed activity is derived as the sum of the dilation at fixed composition and the dilation due to absorption of diluent. Experiments are reported on the dependence of the equilibrium retractive force on elongation for cross-linked polydimethylsiloxanes (PDMS) exposed to benzene or hexamethyldisiloxane vapor at regulated activities. Volume fractions of samples covered the range v2 = 1.00 to v2 ≈ 0.30. With the choice of m = ½ the elastic behavior of a given polymer is well represented by one combination of values for C1 and C2 at all dilutions by either diluent. The dependence of the Mooney-Rivlin (C2) term on volume is thus established, at least for PDMS, and the scope of the semi-empirical free energy expression and its consequents is greatly enlarged. Values of χ deduced from the equilibrium swelling of the unstrained networks exposed to benzene at various activities are in excellent agreement with those obtained previously from vapor pressures and osmotic pressures on linear PDMS. The results of Allen, Kirkham, Padget, and Price on the elastic behavior of natural rubber are discussed, with particular reference to the coefficients of dilation with elongation which they determined at fixed composition. The present results lend strong support to the principle of additivity of the free energies attributable to the network and to the bulk liquid system, respectively. This principle is fundamental to the analysis of rubber elasticity.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 775-786 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The relaxation modulus G(t) and the stress decay after cessation of steady shear flow were measured on concentrated solutions of polystyrenes in diethyl phthalate. Ranges of concentration c and molecular weight M of the polymer were from 0.112 to 0.329 g/ml and from 1.23 × 106 to 7.62 × 106, respectively. The relaxation spectrum H(τ) as calculated from G(t) for the solution of very high M was found to be composed of two parts. One, at relatively short times, was a broad distribution (plateau zone) with height proportional to c2. The second, at the long-time end, was very sensitive to concentration and gave rise to a maximum in H(τ) for very high concentrations. The behavior of H(τ) at long times was examined quantitatively by evaluating the longest relaxation time τ10 and the corresponding relaxation strength G10 from G(t) and from the stress decay function, on the assumption of a discrete distribution of relaxation times at long times. The longest relaxation time was approximately proportional to M3.5, even at relatively low concentrations where the zero-shear viscosity was not proportional to M3.5. The strengths of relaxation modes with the longest few relaxation times are proportional to the third power of concentration.
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  • 10
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 825-834 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: EPR and matrix ENDOR spectra have been examined for polyenyl radicals in γ-irradiated PVF, PVF2, PVC, and PMMA polymers. Proton matrix ENDOR is observed for all four polymers, and fluorine matrix ENDOR for PVF and PVF2. By line shape analysis of the ENDOR spectra obtained under comparable conditions, delocalization diameters for the unpaired electron of the polyenyl radical in each polymer are obtained. These diameters indicate extensive delocalization over 5-7 carbon double bonds for the polyenyl radicals investigated. It is suggested that these conjugated and crosslinked radiation products account for the observed nondevelopment of electron beam resist PMMA material at high radiation charge densities.
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  • 11
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 835-850 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A systematic study of the dispersion curves of the refractive indexes of nylon 6 yarns was made. The parameters were the draw ratio and strain. The measurements show that the dispersions of the refractive indexes n∥ and n⊥, parallel and perpendicular to the fiber axis, are equal, independently of draw ratio and strain. The average dispersion equals nF - nC = 109 × 10-4. Consequently, the birefringence is, within experimental accuracy, independent of the wavelength. The refractive indexes and the birefringence show a change in trend at 10-12% strain. This point corresponds to the yield strain in the stress-strain diagrams. The inference is that beyond the yield point the overall molecular orientation must increase less strongly with strain than before. An analysis shows that the Lorentz-Lorenz relation holds for the average refractive index n̄ = ⅓ (n∥ + 2n⊥). So the change in n̄ versus draw ratio is mainly due to the change in density. By applying the Lorentz-Lorenz relation to the change of n̄ on straining, a value of Poisson's ratio (μ) could be derived. The average value found for nylon 6 yarns was μ = 0.48, which means that the density hardly changes with strain.
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  • 12
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 901-908 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Improvements in the 13C NMR Grant and Paul parameters as applied to polymers have been obtained by noting that the “corrective terms” can be temperature-sensitive. A corresponding temperature sensitivity was not observed for the primary parameters, α through ∊. Results are given for a hydrogenated polybutadiene and six different ethylene-1-olefin copolymers where the standard deviation between calculated and observed chemical shifts has been improved from 1.04 to 0.30 ppm. Since the “corrective terms” in the Grant and Paul empirical analyses of chemical shifts reflect the conformational character of polymers, it is shown that values for these terms can best be obtained directly from the system under study.
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  • 13
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 929-946 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Persistent polarization in poly(vinylidene fluoride) (PVDF) thermoelectrets prepared under high electric field strengths has been studied by measurements of surface charge and piezoelectricity. An anomalous heterocharge appears after the normal homocharge disappears. A model is proposed to explain the surface charge phenomena; the anomalous heterocharge is expressed as a sum of a hidden homocharge and a hidden heterocharge. It is concluded that the anomalous heterocharge as well as the apparent homocharge are not responsible for the piezoelectricity of PVDF electrets. The piezoelectricity is shown to depend on the structure of the original PVDF films or the amount of β-form crystals. However, the piezoelectricity is not attributed to stress dependence of the spontaneous polarization in the β-form crystal of PVDF, but to the hidden polarization which bring about the anomalous heterocharge. The hidden polarizations are attributed to trapped charges.
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  • 14
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 977-983 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric behavior of poly(diethyl siloxane) supports the adiabatic calorimetric findings of Beatty and Karasz. In particular, a sub-Tg transition is observed near -180°C at 100 Hz, the glass transition near -135°C at 100 Hz, and a first-order transition near -70°C (crystal-crystal transformation). This glass-transition temperature is the lowest reported polymeric glass transition for polymers.
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  • 15
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1011-1021 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new model in which solvent molecules are regarded as discrete particles is used for investigating the influence of solvent orientation near a polymer chain and of the anisotropy of the internal electric field on the Kerr effect in a polymer solution. The relation derived for the Kerr constant consists of two parts containing nine terms each in the general case (the physical meaning of the terms is briefly discussed). Relations for the above effect in a nonpolar isotropic solvent, and explicit calculations of the Kerr constant for a simple model of a rigid polymer molecule are given.
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  • 16
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2129-2134 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The peel strength found in the trousers-type peeling process is treated for the case in which the adherends, assumed to be flexible but inextensible are bonded by rubbery viscoelastic adhesives.Taking into consideration energy dissipation during deformation of the adhesive, Griffith's criterion is extended to the peeling of viscoelastic materials. For the peeling force per unit width f it is deduced that 2f = Γ + u′h, where T is twice the surface energy, u' is the energy dissipation per unit volume of adhesive, and h is the thickness of the adhesive layer. Values of u' obtained from peeling tests for various thicknesses are compared with those from the tensile tests and found to agree with the above relation. The deduction that the peel strength is independent of the thickness for adhesives with no energy dissipation is also verified experimentally.
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  • 17
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2183-2194 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Melting and crystallization behavior of polytetrafluoroethylene as polymerized in emulsion and suspension is shown to depend on molecular weight. DSC heating curves for virgin PTFE with low molecular weight below 3 × 105 have a single peak, whereas curves for higher molecular weight samples have double peaks. With increasing heating rate the areas of higher melting peaks become larger than the lower melting peaks. The morphology of polymer exhibiting double melting peaks is mainly folded ribbons or granular particles. The phenomenon of double melting is explained on the basis of two different crystalline states which correspond to the “fold regions” and the “linear segments” in a folded ribbon.The melting temperature of virgin PTFE is almost constant at ca. 330°C for molecular weights below 1 × 106, and rises as the molecular weight increases above 1 × 106. The heat of melting of virgin PTFE is nearly independent of molecular weight.On the basis of these results, we propose a model for melting and crystallization of low and high molecular weight PTFE and for the crystal structure.
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  • 18
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    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2253-2257 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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  • 19
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    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2289-2298 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The low-frequency (10-3 to 5 × 10-1 Hz) dynamic mechanical properties were obtained over the temperature range of 25 to 96°C for 1,5-trans-polypentenamer networks prepared in the presence of 0,0.01, 0.02, 0.04, 0.1, 0.2, and 0.4% dicumyl peroxide. For comparison, similar properties of 1,4-polybutadiene crosslinked with 0.02% dicumyl peroxide were also measured. Superimposed curves for the components of the dynamic compliance, Jp′ and Jp″, reduced to 25°C were obtained and the retardation spectra L were calculated over a range of four logarithmic decades deep in the rubberlike region. It was found that networks containing 0.04 and 0.1% DCP have a small loss maximum Jp″ in the reduced frequency region log ωaT between -2 and 0 which can be assigned to relaxations of untrapped entanglements. The values of (Jp′ - 1/ωη) for very lightly crosslinked polypentenamer networks approached equilibrium very slowly compared to 1,4-polybutadiene crosslinked to the same degree, which suggests the participation of very long retardation times of this polymer which is also probably reflected in the comparatively high values of C2 of the Mooney-Rivlin equation.
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  • 20
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2331-2343 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic mechanical properties of a number of ultra-highly drawn polyethylenes have been studied over a wide range of temperature. It is shown that the materials possess low temperature Young's moduli as high as 1.6 Mbar, a figure which approaches the theoretical and experimental values for the c-axis crystalline modulus of this polymer.The α and γ relaxation processes are still clearly discernible even at highest drawn ratios (ca. 35) and a quantitative analysis of the results, using structural data obtained from broad line nuclear magnetic resonance (NMR) measurements, suggests that the data are consistent with a modified series model.
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  • 21
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2385-2390 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the initial stage of the development of transcrystallinity, nuclei appear sporadically on the substrate. The growth rate and melting temperature of the transcrystalline region are found to be the same as those of spherulites nucleated in the bulk of the polymer. Nucleation densities ns at the interface, and nb in bulk, for the crystallization of isotactic polypropylene, poly(ethylene oxide), and poly(butene-1) in contact with various substrates, have been measured by counting the number of spherulites generated. Despite variations in the results from various causes, the quantities ns and ns/nb are useful parameters for characterizing the nucleating ability of various substrates.
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  • 22
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2391-2400 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the melt crystallization of isotactic polypropylene, poly(ethylene oxide) and poly(butene-1) in contact with substrates, the existence of a fixed number of nucleating sites on the substrate surfaces has been established. When these sites become active successively (the transient in the number of nuclei is long) during crystallization, pseudohomogeneous nucleation on the substrate occurs. Nucleation rates for poly(butene-1) and poly(ethylene oxide) on substrates and in bulk have been measured. These data can be used for comparing the nucleating ability of substrates. Estimates of the variation of bulk nucleation rates from one volume element to another as well as for repeated crystallization within a given volume element have been included. Finally, the temperature coefficients of heterogeneous nucleation rates have been combined with the temperature coefficient of spherulitic growth rate of poly(butene-1), to yield values of the interfacial energy parameters appearing in the theory of heterogeneous nucleation. The quantitative characterization of the nucleating ability of substrates by this method is an improvement over the mere use of nucleation densities or nucleation rates.
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  • 23
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 19-34 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Experiments were performed to determine the effects of strain rate, temperature, and pressure on the flow stress of polyethylene and Lexan polycarbonate deformed in shear. The results were analyzed to determine the activation enthalpy and the shear and dilatation activation volumes of the rate-limiting mechanism of the deformation process. Results show that the activation event involves a volume containing several monomer units and that this volume must dilate by as much as 7% during the activation event. The activation enthalpy was approximately 2.5 × 10-12 erg for polyethylene and 1.1 × 10-12 erg for polycarbonate. The rate-limiting mechanism for polyethylene seemed to be unchanged by plastic strains of up to 250%.
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  • 24
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 703-714 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Stress relaxation and moduli of elasticity of the composite system crosslinked poly(2-hydroxyethyl methacrylate) (PHEMA)-glass beads were studied dry and swollen in water to equilibrium state over the temperature range 5-170°C. The moduli of the composites in the dry state increased with increasing filler concentration, while those of the composites measured in the swollen state up to the volume concentration of the filler vf′ ≅ 0.15 decreased. In this respect the composites behaved as porous systems, i.e., as polymers with macroscopic defects. This effect was explained as a consequence of weak filler-matrix interaction. The results were compared with the existing theories of moduli of the composite materials.
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  • 25
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 737-752 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of dielectric constant and loss, broad-line nuclear magnetic resonance, and differential thermal analysis of concentrated solutions of poly(γ-benzyl-L-glutamate) (PBLG) were carried out to determine the effects of intermolecular interactions on the mobility of the side group and the solvent (dichloromethane or dioxane). Only one dielectric loss peak due to the cooperative motion of the side group and the solvent was found. The activation energy of this relaxation process varied from 3 to 47 kcal/mole with increasing concentration of PBLG from 20 to 100% by weight accompanied with steep increases at about 40 and 80%. This result is explained as due to entanglement of neighboring side groups. In NMR, narrowing of the line was observed near the temperature where the dielectric loss was observed. The glass transition was also observed by differential thermal analysis. From these results it was concluded that the relaxation observed in PBLG solution and in pure PBLG have the nature of primary or α relaxations.
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  • 26
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 815-824 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fourier transform infrared spectra have been obtained for polyethylene irradiated in oxygen and nitrogen atmospheres. The spectra before and after irradiation have been compared by digital subtraction. The difference spectra are indicative of changes caused by irradiation. Crosslinking and chain scission reactions produce the observed changes.
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  • 27
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 857-858 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 28
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 871-871 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 29
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 873-888 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A simple theory for the relaxation of concentration fluctuations in polyelectrolyte solutions is presented, and particular results for the high-salt and no-salt limiting cases are discussed.Autocorrelation functions for the fluctuating intensity of scattered light from dilute aqueous solutions of poly(L-lysine HBr) (PLL-HBr) with and without added salt have been observed over a wide range of pH. The observed autocorrelation functions are in general very satisfactorily represented by single exponentials except at high pH (〉10.5), where considerable aggregation is manifested. Solutions of PLL HBr without added salt exhibit extraordinary behavior, evident at low pH, involving a species with a very slowly decaying autocorrelation function. Though this species is readily annealed to a more ordinary individual free-molecule form by cycling the pH to 9.5 or higher and back, the resulting molecules are found to require unusually long times to reach internal configuration equilibrium under low pH conditions. Solutions of PLL-HBr in 0.2M NaBr and 0.1M NaCl are apparently free of similar extraordinary effects and show the normal isothermal helix-coil transition accompanied by a 15-30% rise in the diffusion coefficient to a maximum at pH 10.5, which is interpreted in terms of a change in molecular dimension of an interrupted helix.The predicted K2 dependence of the reciprocal relaxation time and enhancement of the apparent diffusion coefficient of the polyelectrolyte in the absence of salt is confirmed.
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  • 30
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 961-970 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Convenient x-ray diffraction instrumentation for assessing PVC order is described. A reflectance diffractometer, copper radiation, a monochromator, and a proportional detector are used to make measurements on low molecular weight, highly crystalline PVC prepared using chain-transfer agents. Interpretation includes a correction for air scattering, employment of a trimodal noncrystalline pattern, and the calculation of crystallinity from the ratio of the crystalline to the total integrated intensity. The results are reasonably insensitive to the assumptions made. The noncrystalline pattern used is taken to indicate a single, partially ordered mesomorphous phase. A whole polymer prepared in the presence of butyraldehyde, a fraction therefrom prepared by precipitation, and a similar fraction terminated by butyl mercaptan have similar molecular weights (M̄n ca. 1600) and crystallinities of 30, 44, and 44%, respectively. Fractionation apparently effects a separation with respect to syndiotactic content, and the resultant crystallinity appears to be the highest valid x-ray value reported to date for a PVC polymer, irrespective of polymerization variables, fractionation procedure, or molecular weight. The order in these polymers is due in part to their greater syndiotacticity (about 64% for the fractions by 13C NMR spectroscopy), although a more favorable tactic placement distribution may be involved in addition to a possible effect of molecular weight itself.
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  • 31
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 997-1009 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Depolarization ratios ρ have been measured over ranges of temperature T and molecular weight M for polystyrene (PS) dissolved in cyclohexane (1002 cm-1 Raman band) and for poly(dimethyl siloxane) (PDMS) dissolved in benzene (2907 cm-1 Raman band). The ranges in the case of PS are 15 〈 T 〈 65°C and 2 × 103 〈 M 〈 4 × 105 and in the case of PDMS are -3 〈 T 〈 60°C and M = 104. Measurements were also made of PDMS radii of gyration using conventional light scattering. The results are interpreted in terms of a theory connecting rotational isomeric populations with polymer extension. In the case of PDMS, an experimental value of the proportionality constant for trans isomers (D2 = -3.9 ± 0.9) is deduced. This is closer to the theoretical value than previous estimates but there is still some discrepancy. In the case of PS the isomeric changes resulting from extension are independent of M for M 〉 104. Deviations are observed for lower M.
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  • 32
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1049-1056 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two low-temperature dynamic mechanical relaxations have been observed in networks formed by copolymerization of poly(1,2-propylene fumarate) and poly(1,2-propylene phthalate fumarate) with styrene. The γ relaxation which occurs around -100°C (1 Hz) is induced by small amounts of water, while the broad γ′ relaxation is reduced in height by the presence of water. Neither xylene nor 1,2-propylene glycol induced a γ relaxation. The γ relaxation was ascribed to motions involving a fumarate ester group-water complex.
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  • 33
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1063-1070 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A novel method for determining the polymerization mechanism and the kinetic rate constants from the molecular weight distribution is proposed. The particular criterion function used as basis for parameter adjustment is \documentclass{article}\pagestyle{empty}\begin{document}$$ \mathop {{\rm Min}}\limits_\theta \int_0^\infty {\left[ {y\left( {r,\theta } \right) - y_{\rm E} \left( r \right)} \right]^2 dr} $$\end{document} where θ is the vector of dependent variables, y(r, θ) is the theoretical molecular weight distribution for the assumed polymerization mechanism, and yE(r) is the experimental molecular weight distribution which is a function of the chain length r. A form of the gradient method of optimization was used to solve the criterion function. The proposed method is particularly powerful since the whole molecular weight distribution is utilized.
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  • 34
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1263-1267 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
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  • 35
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1285-1300 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The strength of adhesion has been determined experimentally for an elastomer layer coupled to a rigid substrate by interfacial chemical bonds of varying surface density. Sites for interfacial bonding were obtained by treating glass plates with mixtures of vinyl-and ethylsilanes in varying proportions. A layer of polybutadiene was then applied and cross-linked in situ by a free-radical process. Formation of interfacial bonds to vinyl groups (when present) on the glass substrate is inferred from the proportional increase in strength of adhesion under near-equilibrium conditions, i.e., at low rates of detachment and at high temperatures. A 35-fold increase in strength was found for vinylsilane, relative to ethylsilane, in rough agreement with the relative magnitudes of the strengths of covalent and dispersion bonds. However, the absolute magnitudes were much greater than predicted, by a factor of about 25 in both cases. This is attributed to the polymeric character of the elastomer: many molecular bonds must be stressed in order to detach or rupture one.4 In agreement with this hypothesis, the strength of adhesion decreased with increasing crosslinking. Anomalously high adhesion was found with clean glass. It presumably reflects a specific bonding mechanism of unknown type.
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  • 36
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1347-1351 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dynamic mechanical and dielectric properties of amorphous regenerated films of silk fibroin were studied as a function of temperature. A mechanical loss tangent peak at about 175°C may be due to the segmental motion of the main chains in the amorphous silk fibroin film. The dynamic modulus of the amorphous silk fibroin increased at 185°C due to the crystallization of the silk fibroin. Dielectric loss tangent peaks were observed at about -40°C and 175°C at 1 kHz. The former is ascribed to the local motion of the amorphous silk fibroin with absorbed water, while the latter seems to originate from the segmental motion of the main chains and the crystallization of silk fibroin.
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  • 37
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1353-1363 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of isomeric polyester block copolymers were synthesized by coupling hydroxyl-terminated poly(hexamethylenesebacate) (HMS) and poly(2-methyl-2-ethyl-1,3-propylene sebacate) (MEPS) with hexamethylene diisocyanate. Poly(HMS) is crystalline, whereas poly(MEPS) is amorphous. All of the block copolymers, including one containing only 28% HMS were found to crystallize. DSC, density, and optical microscopy were used to measure the thermal transition temperatures and the degree of crystallinity. The data indicate that block copolymerization causes a small depression in the melting point and that the degree of crystallinity of the HMS block in the copolymer is more a function of molecular weight than it is of copolymer composition. Crystallization appears to be the major driving force for phase separation in this isomeric copolymer system.
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  • 38
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1387-1405 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The multiple melting transitions previously reported for cis-polyisoprene have been related to different morphological species observed in thin films using transmission electron microscopy. Two distinct types of spherulitic lamellar crystal have been identified which have characteristic growth rates, lamellar thicknesses, and fold planes.In addition to the α-lamellar crystals, which grow in prestrained films with the a axis perpendicular to the stretch direction, a second type of lamellar crystal was identified with the b axis perpendicular to the stretch direction: β-lamellae. From an analysis of the kinetics of growth and the variation of lamellar thicknesses with crystallization temperature, values of the side and surface free energies of the two types of lamellar crystal have been calculated.
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  • 39
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1467-1479 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new method is suggested for the experimental determination of the dependence of the relaxation times on the temperature in dielectrics for which the time-temperature superposition principle is valid. The method makes possible the determination of this dependence for a separate relaxation process (for instance, for the β-relaxation process) over a wide temperature range by means of comparatively simple mathematical operations which are only slightly sensitive to experimental errors. Two or more discharge-current curves, measured with temperatures increasing in an arbitrary way with time, are used for this purpose.
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  • 40
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Heats of mixing of methanol with butyl isobutyrate and with oligomers of butyl methacrylate (monomer to tetramer) having a butoxyl group on one chain end have been measured. To discuss the effect of hydrogen bonding on the heat values, it is appropriate to correlate the heat per mole of binding sites with the binding site fraction. This dependence can be described by a single curve for all oligomers studied, in contrast to the results obtained in a previous paper for the same oligomers with chloroform. This fact suggests that the binding parameters for methanol are not influenced by the degree of polymerization.
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  • 41
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1603-1611 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Experiments on electro-osmosis of water through a cellulose acetate membrane have been reported and the data analyzed in the light of nonequilibrium thermodynamics. The linear phenomenological equations have been found to be valid. Study of the directional dependence of phenomenological coefficients has revealed the anisotropic character of the membrane. Efficiency of energy conversion for both electro-osmosis and streaming potential has been calculated and the results have been analyzed in the light of thermodynamic theories.
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  • 42
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2079-2090 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dielectric experiments were performed in the β temperature region on poly(ethylene terephthalate) films of different draw ratios. The proportion of various conformations, crystallinity, and orientation were estimated from infrared, density, and birefringence measurements. The dielectric relaxation strength was determined from the Cole-Cole plot of the dielectric constants over a wide frequency range. An attempt was made to modify the Fröhlich equation, originally for isotropic systems, for application to systems of oriented dipoles. When the experimental data are analyzed through this modified equation, it is evident that the changes in the dielectric constants of PET with stretching could not be accounted for by improvement in the alignment of chain molecules alone. The relative abundance of the trans conformation, both crystalline and amorphous, and gauche conformation appears to be a factor which cannot be ignored. The calculation indicates that the dipole moment seems to be greater in the trans conformation than in the gauche conformation.
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  • 43
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2173-2181 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The unit cell of poly(tetramethylene terephthalate) is triclinic with parameters a = 5.96 Å, b = 4.83 Å, c (fiber axis) = 11.62 Å, α = 115.2. β = 99.9, and γ = 111.3°; space group P1, calculated crystalline density 1.41 g/cc. The plane of the benzene ring is found to be inclined by about 15° from the fiber axis, contributing to a shortening of the fiber period as compared to the period expected on the basis of analogy with other members of the terephthalate ester series. The remaining shortening of the fiber period occurs in the —O—°CH2—°CH2—segment of the chain. No abnormally short distances among neighboring chain atoms were observed. A typical texture pattern was found in specimens of this polymer that were cold rolled and subsequently annealed. In this texture the c axis of the unit cell is highly oriented in the rolling direction; the a and b axes of the unit cell are oriented preferentially so that the terephthalate residue lies as close as possible to the plane of rolling.
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  • 44
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2241-2245 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
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  • 45
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1-7 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It has been suggested that transverse sectioning of natural cellulose fibers can be used to test ideas about microfibril structure. This proposal has been examined theoretically and numerical calculations of the weight-distribution curve of sectioned chains are given for several different models. These calculations illustrate the effects that different types of chain folding have on the sectioned size distribution. The difficulties involved in the practical execution of this type of experiment are discussed and it is concluded that fiber-sectioning experiments described in the literature do not disprove the folded-chain hypothesis.
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  • 46
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 35-41 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Graessley's entanglement theory of viscosity modified by a frictional viscosity parameter ηfric is applied to data on solutions of polystyrene in diethyl phthalate at various concentrations and different temperatures. All the data modified give a single master curve over the entire rates of shear, as obtained previously with polydimethyl-siloxanes of various molecular weights and their solutions of various concentrations. The zero-shear viscosity η0, the upper Newtonian viscosity η∞, and ηfric are compared. Three activation energies for flow are estimated from η0, η∞ and ηfric, and are compared. The result suggests that the flow behavior in the upper Newtonian region is much more dependent on ηfric than on the entanglement viscosity term ηent. The ratio of zero-shear entanglement viscosity ηent,0 to ηfric can be used as a measure of the non-Newtonian behavior of the present solutions. Non-Newtonian behavior of the investigated polymer solution becomes appreciable at about ηent,0/ηfric = 2.5. These results are in agreement with previous conclusions based on comparison between η0, η∞ and ηfric for polydimethyl-siloxanes and their solutions.
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  • 47
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 95-112 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscosity of a number of molten polystyrenes and polypropylenes obtained in various ways from solutions is found to be very strongly dependent on the history of dissolution of the polymer (the concentration of the solution and the “goodness” of the solvent), and on the presence of certain organic oligomeric compounds in very small amounts. The viscosity of the melt may be orders of magnitude less than that of the original samples. The present discussion of these effects is based on the concept of structure formation in amorphous polymers. The structure formed on the solution appears to be very stable with respect to heating and prolonged standing at elevated temperature, although it (and hence the viscosity) strongly depends on the initial concentration of the solution and the nature of the solvent. The role played by additives, present in amounts of small fractions of a percent, is accounted for by the fact that the melt retains the microheterogeneity of the medium. The material moves without its micromosaic structure being disturbed, and the role of the additives is reduced to surface (with respect to structural elements) phenomena.
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  • 48
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 667-674 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The bond correlation function for a macromolecular model chain on a tetrahedral lattice is derived by considering elementary three-bond and four-bond motions. The method of calculation allows the conformational structure of the chain to be involved in the final equations. Moreover, when the three-bond motions are considered alone, no linearization assumption is required; hence, the theory is valid at short times.
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  • 49
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 727-736 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The fluctuation theory of light scattering for moderately concentrated polymer solutions is extended in a phenomenological fashion to include angle-dependent terms up to sin2 (θ/2). The treatment is based on an uncoupling of the center of mass and segment contributions to the free enthalpy. In particular, equations are derived for three-component mixtures containing two polymer and one solvent component. These are applied near the region of incompatibility. The results are compared with Debye's theory of critical opalescence. It is found that the Debye l parameter should be of the order of magnitude of the radii of gyration of the polymer molecules. This is confirmed by some experiments.
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  • 50
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 765-774 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: To investigate the morphology of unoriented poly(ethylene terephthalate) (PET) films and the selective character of the aminolysis of PET, 67% crystalline polymer samples were degraded with 40% aqueous methylamine at room temperature. The aminolyzed PET samples were subjected to gel permeation chromatography (GPC), viscometry, electron microscopy, and small-angle x-ray diffraction (SAXD). Weight loss and density crystallinity measurements were also made.After 24 hr of aminolysis, the amorphous regions and chain folds were completely removed. The long molecular chains in the semi-crystalline polymer were reduced to monodisperse rods having a molecular weight of 1,800. The corresponding lamellar thickness was calculated to be 101 Å, consistent with the x-ray diffraction and electron microscope (EM) measurements. The EM photographs of “stripped” crystals show the lamellar structure previously found for other selectively degraded polymeric materials. The weight of crystalline debris remaining was consistent with the initial crystallinity. After degradation the crystallinity as determined by density was 96%.
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  • 51
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 799-813 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A study has been carried out of the changes in the x-ray diffraction patterns which occur when oriented fibers or tapes of poly(trimethylene terephthalate) (3GT) and poly-(tetramethylene terephthalate) (4GT) are subjected to mechanical tensile stress. Although the polymers show very different behavior in detail, in both cases comparatively large reversible lattice strains are observed (∼ several %). The diffraction pattern of 3GT changes monotonically with increasing macroscopic strain, suggesting that the lattice responds immediately to the applied stress, and deforms as though it were a coiled spring. In 4GT, on the other hand, there is no detectable change in the x-ray diffraction pattern at low macroscopic strains, i.e., low values of the applied stress. At higher stresses, changes in the pattern occur which suggest a definite change in the crystal structure. Finally at the highest values of applied stress, the lattice deformations cease to increase. A preliminary discussion is presented of the relationship of these x-ray diffraction results to the mechanical stress-strain behavior.
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  • 52
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 859-861 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 53
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 871-871 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 54
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 909-927 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Tridimensional associations of lamellar polymer single crystals, grown from dilute solutions, are described as derived from their sedimentation patterns. These associations include interlocked crystals and decorating crystal halves. The origin of these crystals and their mutual orientation are discussed and tentatively interpreted by specific interactions between the fold surface and the crystallizing chains.
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  • 55
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 953-960 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mechanical degradation and mechanochemical polymerization in polystyrene-styrene-cyclohexanone mixtures have been studied by ultrasonic irradiation at 60°C. The number of fresh polymer chains after the degradation is 2 × 10-5 mole l-1 hr-1. The rate equations for mechanical scission and mechanochemical polymerization have been deduced. The rate equation for mechanical scission was found to be in agreement with the expression of a previous paper. In addition, the rate equation for mechanochemical polymerization is not essentially different from that for the general radical polymerization in the presence of solvents. The kinetic chain length for polymeric free radicals in the polymerization process has been calculated. The mechanochemical polymerization of styrene was initiated by only one of the two kinds of end radicals after mechanical scission of polystyrene. The molecular weight distributions of the samples after the degradation and the polymerization have been compared and discussed.
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  • 56
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 985-995 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: As previously shown, by electrospraying dilute polystyrene (PS) solutions gas phase macroions can be produced. Degradation of the PS in the electrospray was tested by collecting the electrosprayed PS and measuring its number-average molecular weight osmotically. About 10% degradation was observed when using negative voltages, but the degradation was considerably reduced when the electrospray occurred in the presence of SF6 gas. No degradation was apparent in the case of positive sprays. A quantitative analysis of the results was made difficult by a small less of PS in the nitrogen gas stream and by diffusion of lighter ions to the vertical wall of the spray chamber. The latter effect did not occur at the highest spray voltage used, -24 kV.
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  • 57
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1071-1083 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(vinylidene fluoride) exists in three crystalline forms. Optimum conditions for preparing form III were established by infrared spectroscopy, differential scanning calorimetry, and x-ray diffraction measurements. Form III is easily obtained by annealing mats of solution-grown crystals of form II at 175-185°C and is also preferentially formed by isothermal crystallization from the melt between 165 and 175°C. Below 165° crystallization of form II is favored. The melting point of form III is higher than that of form II.
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  • 58
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1115-1132 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By a study of two ternary systems, 4-heptanon-1-chlorobutane-poly(methyl methacrylate) and 2-butanol-1-chlorobutane-poly(methyl methacrylate), differing only in one component of the mixed solvent, two types of demixing behavior are demonstrated: i.e., a monotone change with composition of the mixed solvent (monotony), of which the first system is a good example, and the synergistic behavior (cosolvency) exhibited by the second system. The situation can be seen most clearly from the binodal edges (precipitation thresholds as a function of solvent composition) which were constructed from various types of sections through the binodal surface of the systems.In order to compare experimental results with theoretical calculations, we first characterized the binary subsystems. The polymer solutions, representing conventional (endothermal) theta systems, were investigated by light scattering and cloud point measurements. For the cosolvent 2-butanol-1-chlorobutane the necessary thermodynamic information was accessible from vapor pressure measurements. Applying the Prigogine-Patterson theory to the polymer solutions and using the single-liquid approximation of Scott for the ternary systems yielded theoretical binodal edges in good agreement with experiment except for the branch belonging to mixed solvents rich in 2-butanol. This finding is explained by an abnormal amplification of preferential solvation effects due to the existence of an association equilibrium of the alcohol via hydrogen bonds.
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  • 59
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1177-1186 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: High-density polyethylene filaments prepared by a solid-state deformation in an Instron capillary rheometer show unusually high crystal orientation, chain extension, axial modulus, and ultimate tensile strength. The Young's modulus and ultimate tensile strength have been determined from stress-strain curves. Gripping of this high modulus polyethylene has been a problem heretofore, but the measurement of ultimate tensile strength has now been made feasible by a special gripping procedure. Tensile moduli show an increase with sample preparation temperature and pressure. Values as high as 6.7 × 1011 dyne/cm2 are obtained from samples extruded at 134°C and 2400 atm and tested at a strain rate of 3.3 × 10-4 sec-1. The effect of strain rate and frequency on modulus has also been evaluated by a combination of stress-strain data and dynamic tension plus sonic measurements over nine decades of time.
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  • 60
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1233-1245 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: ESR spectra have been observed from several polymers (polyethylene, polypropylene, polymethylmethacrylate, polytetrafluoroethylene, and polybutadiene) which were mechanically fractured in vacuum at 77°K. The spectra permit identification of the free radicals produced in chain scission. It has been demonstrated for the polymers of the type such as polypropylene and poly(methyl methacrylate), that the mechanical fracture produces two different scission radicals in pairs, namely, The results indicate convincingly that microscopic scission of polymer chains is caused by macroscopic destruction of polymeric material. The critical molecular size for mechanical rupture of polyethylene chains was experimentally determined to be a degree of polymerization between 70 and 100. This size agrees fairly well with the value predicted from a theoretical model.
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  • 61
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1275-1284 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An investigation of steady state and transient photoconductivity in films of poly-(N-vinylcarbazole) equipped with SnO2 and metal electrodes is described. The studies have shown that photoinduced charge transfer, leading to hole injection into the polymer film, takes place with photons of energy greater than 1.8-1.9 eV. Dark conductivity studies on samples equipped with grounded guard rings have shown that carriers originating in the bulk of the polymer film dominate the dark current when the metal electrode is at negative bias. Thermionic hole emission from the SnO2 electrode is not observed.
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  • 62
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1315-1331 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The density of mature crazes initially increases linearly with stress and then more rapidly at higher stresses. Once the crazes become observable then density was independent of time. The lowest stress at which an appreciable density of crazes was produced corresponds to the proportional limit. The average velocity of mature crazes was constant for a given stress and varied exponentially with the stress. The velocity depended on stress in the same way that the post-yield point stress depended on strain rate, whereas the yield point varied differently being a nonlinear function of the logarithm of the strain rate.The density of crazes was quantitatively related to the concentration of surface defects at which the crazes nucleate. The craze velocity was directly related to the diffusion coefficient of N2 into the polymer. The analysis indicates that bulk diffusion of the N2 governs the craze velocity and that plasticization of the tip of the craze is most important for the nucleation and growth of a craze in PCTFE.
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  • 63
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The α and β dielectric relaxations of poly(hexamethylenesebacate) (HMS), poly(2-methyl-2-ethyl propylenesebacate) (MEPS), poly(1,4- dimethylbutylene sebacate) (DBS) and block copolymers of HMS and MEPS have been studied. The α relaxation is amenable to a W.L.F. analysis and is associated with the glass transition of the polymers. This relaxation moves to higher temperatures with increasing HMS content in HMS/MEPS block copolymers. All the polymers studied exhibit psuedo-activation energies of ∼32 kcal/mole at the glass transition. It is concluded that because the superposition principle is operative in the block copolymers, the glass transition must be very similar in both polymers and morphology and degree of crystallinity do not greatly affect this transition. The β relaxation which has been associated with segmental relaxation of polymethylene segments in polymers is also shown to be a function of HMS/MEPS block copolymer composition and chemical structure. This relaxation takes place at lower temperatures with increased HMS content in the blocks and also shifts to lower temperatures with side chain substitution adjacent to the carbonyl group in the polymer. It is concluded that the β relaxation takes place in the amorphous and crystalline regions of the polymer.
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  • 64
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1461-1465 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 65
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1491-1499 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric constant of solutions of poly(γ-benzyl-L-glutamate) (PBLG) in dichloromethane shows a jump near 195°K, irrespective of frequency. Therefore, the discontinuity is not a dispersion phenomenon but a phase transition in the thermodynamic sense. The transition temperature is independent of the concentration in the range from 0.01 to 10% by weight, but it increases linearly with the logarithm of the molecular weight of PBLG. The height of the jump depends strongly on frequency, concentration, and molecular weight. The viscosity also changes abruptly at 195°K. These results suggest that the PBLG molecule forms a cluster like a liquid crystal or is in a random coil state below the transition point.
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  • 66
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1481-1490 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The small-angle x-ray scattering (SAXS) from glassy poly(methyl methacrylate) has been measured using a Bonse-Hart system. The data cover the angular range (2θ) between 20 sec and 2 deg. After correcting for absorption, background, and beam divergence, the data have been placed on an absolute basis by comparison with the scattering from a standard silica suspension. The corrected absolute intensity decreases strongly with increasing angle over the range between 20 sec and 30 min, and is nearly constant between 30 min and 2 deg. The magnitude of the scattering in the constant range, 0.6 (electrons)2 Å-3, is within a factor of 1.5 of the value predicted by the thermodynamic fluctuation theory for fluids applied at the glass transition temperature. The increase in intensity at smaller angles cannot be described by structures on the scale of the nodules reported in highly isotactic PMMA (150-200 Å), but can be well represented by small concentrations of heterogeneities, several thousand angstrom units in size, superimposed on the thermal density fluctuations frozen-in at the glass transition. The bulk structure of this material is well described as a random amorphous solid, containing simple thermal fluctuations and a small concentration of relatively large heterogeneities.
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  • 67
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1515-1532 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The micromechanism of tensile deformation of poly[p-(2-hydroxyethoxy)benzoic acid] fibers is discussed on the basis of a detailed esr study of radical formation. The concentration of primary phenoxy radicals, which were detected during deformation at room temperature as a direct indicator of main-chain rupture, was determined by extrapolating the radical decay curves at various strains to zero time. The relation between the initial radical concentration and the strain is well expressed by the cumulative normal distribution curve. By use of this relation and a model of fiber structure, the distribution of the contour length of tie chains was determined. No radicals were detected during a second stretching cycle until the maximum strain in the first run was exceeded. The deformation model which includes alternating crystalline and amorphous regions connected by tie chains, a distribution of contour lengths of tie chains, and a phase transformation of molecular chains in the crystalline region accounted fairly well for the observed stress-strain behavior of monofilaments in first and second stretching cycles. The comparison between the observed and the calculated radical concentration suggests that statistical factors and other deformation mechanisms have to be taken into account.
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  • 68
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1643-1649 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Experimental results are presented and discussed comparing two techniques for inducing fibrous growth of polyethylene crystals from flowing solutions: a plunging cone device and a standard rotating cylinder (Couette) device. Comparison of crystal “overgrowth” diameter to spacing ratios for the several experiments with predictions based on an earlier postulated model lead to conclusions regarding the model inadequacy. A detailed comparison is made of the melting behavior of crystals produced by both flow fields and those results are discussed in light of a modified model for the growth process presented elsewhere. The conclusion is reached that differences in melting behavior may be attributed to differences in extension of the high molecular weight chains involved in the growth processes occurring in the two different flow fields.
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  • 69
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1665-1673 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The sorption of ammonia by polystyrene was investigated by pulsed nuclear magnetic resonance (NMR) relaxation techniques. The concentration of sorbed gas was determined from the intensity of the gas signal and analyzed by the dual mode sorption model. The relaxation data were used to examine the validity of assuming that the molecules exchange rapidly between sites and that the adsorbed species is relatively immobile. Both assumptions were found to be substantially correct although the possibility that the adsorbed species may have some small mobility (no more than 5% that of the faster moving molecules) could not be eliminated.
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  • 70
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1761-1781 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A rotational cone-and-plate rheometer incorporating a drag-cup torque transducer and a frictionless, wire suspension has been designed and constructed. The instrument design provides for a controlled atmosphere for the sample, including anhydrous conditions necessary for studies on solutions of polymers in strong acids. The rheometer can be used to determine the shear deformation in response to an applied stress, including creep, recovery, and the shear stress in response to an applied steady shear. Both transient and steady-state measurements are possible. Illustrative examples of the instrument performance are given.
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  • 71
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1795-1808 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the vibrational spectrum of a polymer obtained under tensile stress loading conditions, several modes of molecular deformation can lead to different mechanisms of frequency shifting and asymmetric band deformation. Theoretically and experimentally it has been observed that quasielastic deformations (reduction of force constants due to bond weakening under stress), pure elastic bond stretching and angle bending, conformational variations, and several types of chain defects can cause linear shifts in frequency and infrared band distortion. A detailed study of the deformation spectra of isotactic polypropylene and polyphenyl-p-sulfide indicated that quasielastic and elastic mechanisms are the major contributors to frequency shifting, principally affecting stretching and bending vibrational modes. Conformational mechanisms can affect torsional modes whereas the defect mechanism, when present, can cause random distortion of an infrared band. The latter mechanism is difficult to quantize. The extent to which each mechanism contributes to the total spectral deformation can be a function of morphology, macroscopic loading conditions, thermal and strain histories.
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  • 72
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1831-1844 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The abrupt changes in the linear expansion and dilatometric measurements of poly-(ethylene terephthalate) near 70°C indicate that the transition may be first order. DTA and DSC data show the normal heat capacity change at 70°C, while annealing for for 30 min. at 110°C induces further molecular order. Rapid quenching of PET after heating to 120°C yields an amorphous sample and measurement by depolarized light transmission as the sample is reheated shows rapid crystallization occurring near 80°C. With the occurrence of shrinkage near 68°C and apparent recrystallization at slow heating rates by depolarized light analyses, further support is added to the first-order character of this phase transition. Isothermal annealing for short times at temperatures between 50°C and 80°C produces further increases in molecular order. Cyclic and linear PET oligomers do not contribute to the occurrence of the 70°C transition.
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  • 73
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1863-1869 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Energy levels and molecular orbital wave functions of π-electrons in a carbazole ring are calculated by the ω-method. The result agrees well with observed optical absorption spectra of carbazole and poly(N-vinylcarbazole) (PVCA). Molecular orbital wave functions are obtained for a PVCA chain in a 3/1 helix. The overlap integral between adjacent carbazole rings is evaluated for each molecular orbital of the ring. The result affords evidence for hole conduction in PVCA and explains the photoconductivity spectrum under high de field.
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  • 74
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1903-1911 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fracture energies have been measured for two types of polybutadiene elastomer, crosslinked to various extents and torn under various conditions. Threshold values, ranging from 40 to 80 jm-2, were observed for samples torn at extremely low rates of tearing, at high temperatures, and in the swollen state. These values were found to be independent of temperature and rate of tearing, and also of the degree of swelling and the nature of the swelling liquid, provided a correction is made for the reduced areal concentration of molecular chains. They decreased somewhat with increased crosslinking, in good agreement with theoretical predictions of Lake and Thomas.6 The results for the two elastomers were substantially the same.These observations are strikingly different from those made at normal temperatures and rates of tearing, when large differences in fracture energy were observed between the elastomers, and between samples crosslinked to different extents, due to energy losses from nonequilibrium deformation processes in addition to the energy required for fracture.
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  • 75
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1975-1990 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The 1,4-1,2 additions in three hydrogenated polybutadienes are described in terms of triads of monomer units, average sequence lengths, and branches per 1000 carbon atoms. A test for conformity with Markov statistical behavior shows that the measured triad distributions can be closely reproduced assuming a first-order model. Transition probabilities from the statistical analysis can be used to calculate the relative concentration of any desired sequence. Steric factors during polymerization may lead to the first-order bias in the monomer distribution.
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  • 76
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2069-2077 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The elastic behaviors of simple networks consisting of but a few chains have been calculated on the basis of the James and Guth theory of elasticity. The calculations show that the number of elastically effective chains in a network is less than the actual number of network chains, and that the total number of chain backbone links distribute themselves equally (approximately) among the effective chains. It is also demonstrated that a chain molecular weight distribution could be of consequence in non-Gaussian elasticity. Extrapolation of the findings to a macroscopic network suggests that the number of effective chains is one half the number of network chains, and that each effective chain behaves as if it contained twice as many of backbone links as a network chain.
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  • 77
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2031-2048 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transparent strands of high-density polyethylene of unusually high c-axis orientation have been produced by a solid-state extrusion, involving pressure, temperature, and deformation, in an Instron capillary rheometer. Measured values for tensile modulus are higher than previously reported for any polyolefin. Previous modulus and electron microscopic data are consistent with a strand morphology comprised (≤20%) of of extended chain crystals. The remainder resembles an oriented fibrillar morphology such as found in highly drawn polyethylene. In the present study, fuming nitric acid etching of the ultraoriented strands, in combination with gel permeation chromatography (GPC), has provided incisive structural information. The strands exhibit ≥3X the resistance to acid degradation shown by conventionally drawn polyethylene. GPC molecular weight distributions (MWD) of etched samples show a single broad peak with a prominent high molecular weight tail. The crystal size, represented by the MWD, is in agreement with the crystal long period determined by small-angle x-ray scattering. The absence of multiple peaks in the etched MWD's is evidence of limited chain folding. The extended chain content, determined from the etched MWD's, is a strong function of strand formation temperature and is in agreement with the fraction of extended chains calculated from modulus measurements.
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  • 78
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2091-2102 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Novel ionic polymers of the type x,y-oxyethylene ionenes (x,y-OEI), have been synthesized, for x and y varying from 2 to 5. The 2,2-, 2,3-, 2,4-, and 3,3-OEI are crystalline; the 3,4-, 4,4-, 4,5-, and 5,5-OEI are amorphous. The temperature dependence of the dynamic mechanical properties of these polymers, studied by torsional braid analysis over a temperature range from -170° to +150°C, shows two types of dispersion in each polymer. The dispersions lying between -6° and +90°C appear to be primary dispersions due to the amorphous phase. The dispersions between -110° and 0°C, on the other hand, are attributed to local modes. The temperature of the primary dispersion depends linearly on the charge density along the main chains of the polymer. However, the dependence of the local mode dispersion temperature on the charge density shows no regular pattern. Both dispersions are greatly influenced by the presence of absorbed water. Measurements of Tg at various water contents reveal the existence of abnormal plasticizing effects by water.
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  • 79
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2135-2153 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A Langevin equation of motion for a charged bead-spring statistical chain is written in difference form and the relaxation and equilibrium behavior of the chain is studied by computer simulation. Results are presented for the behavior of end-to-end length h, principal axes of the polymer ellipsoid L1, L2, L3, and chain contour length c in terms of their averages, root mean square values, root mean square fluctuations, orientations, and relaxation strengths and times. The simulation was made with various sets of parameters, bead number N, charge on the bead q, and radius of ion atmosphere around the bead k-1. It is found that 〈h2〉1/2 and 〈L12〉1/2 increase more strongly with increasing q and decreasing κ than 〈L22〉1/2, 〈L32〉1/2, and 〈c12〉1/2, indicating that the chain is expanded in three dimensions and at the same time is extended along the end-to-end direction. The relaxation time τrot of rotation of the end-to-end vector, which is proportional to N2 at q = 0, increases with increasing q and tends to be proportional to N3 for an extended chain, while the relaxation time τconf of the magnitude of h is almost independent of q and is always proportional to N2. It is concluded that the extended chain possesses a well-defined end-to-end axis and the chain rotates as a whole with a relaxation time τrot which is much longer than τconf. The complex viscosity of the chain is calculated from the Fourier transform of the time-correlation function of momentum flux and is found to have a frequency spectrum similar to that observed for aqueous solutions of poly(acrylic acid). The dominant mode appearing in the low-frequency range is evidenced to arise from the rotation of the extended chain.
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  • 80
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2237-2240 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 81
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2195-2219 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stress-induced crystallization of trans 1,4-polybutadiene was studied by observing changes in birefringence, stress, x-ray diffraction, and low angle light scattering during the course of crystallization. From these data, the degree of crystallinity was determined as a function of time, temperature, and elongation. Data were fitted to the Avrami equation, leading to an exponent of the order of unity. Light-scattering patterns suggested the simultaneous existence of two stretched forms: a rod-like structure oriented preferentially parallel to the stretching direction and a deformed spherulitelike growth with its greatest extension perpendicular to the stretching direction.
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  • 82
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2251-2251 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 83
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2281-2288 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A renewed explanatory study is reported on the fold structure and branch location in single crystals of an ethylene-propylene copolymer by means of the ozone degradation method. By analogy with concurrent studies on linear polyethylenes a distribution of fold lengths is inferred, this distribution being broader, more uniform, and spreading deeper into the crystal interior in the case of the copolymer than for the linear polyethylene. Perhaps the most salient points of the work is that in contrast to nitric acid the oxidation by ozone does not obscure then characteristic CH3 infrared absorption band enabling the branch content to be followed during degradation. The single exploratory experiment of the present work reveals that while there is a certain amount of preference for the branches to accumulate near the fold surface, a substantial portion of them can still be located in the crystal interior. The potential of the present method for a more systematic study is indicated.
    Additional Material: 4 Ill.
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  • 84
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2299-2311 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Homogeneous and heterogeneous poly(2-hydroxyethyl methacrylate) hydrogels were prepared by copolymerization of 2-hydroxyethyl methacrylate and small amounts of ethylene glycol dimethacrylate in the presence of water; concentrations of water (V1) in the polymerization mixture and the volume fractions of water (v1) of the gels swollen to equilibrium were 40, 50, 60, 70% by volume, and 0.475, 0.541, 0.669, 0.778, respectively. From the homogeneous (clear) hydrogel (V1 = 40%) preparation, four hydrogels were prepared with v1 = 0.434, 0.418, 0.378, 0.326. Tensile dynamic moduli were measured in the frequency range from 0.006 to 0.6 cps and the temperature range from 0 to 40°C. In these cases, the influence of swelling on the shape of the relaxation spectra and on the monomeric unit friction coefficient was studied. The dependence of the friction coefficient on water concentration was interpreted in terms of free volume. In the heterogeneous (opaque) gel preparations (V1 = 50, 60, 70%), the effect of the aqueous phase in the system on the mechanical behavior was described by a modification of the blending law of Ninomiya. For the systems with V1 = 60% and 70% the shapes of the storage and loss moduli in the main transition region and the friction coefficient were similar to those of the homogeneous gel with V1 = 40%, except for the decrease in absolute value of the storage moduli. For the system with V1 = 50% the shape of the relaxation spectrum changes appreciably and the wedge distribution does not hold.
    Additional Material: 12 Ill.
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  • 85
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2369-2383 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Melt crystallization of isotactic polypropylene (iPP), poly(ethylene oxide), poly(butene-1), and polycaprolactone in contact with various substrates (mostly polymeric) has been studied by hot stage polarizing microscopy. Nucleating abilities of surfaces have been characterized qualitatively by examining the substrate-induced morphologies of the crystallizing polymer. These morphologies have been classified into three groups, depending on whether the substrate is very active (transcrystallinity), moderately active, or inactive as a nucleating agent. The morphologies observed are temperature-dependent, changing from transcrystalline to spherulitic upon increase of the crystallization temperature. At intermediate temperatures, mixed surface morphologies (transcrystalline plus spherulitic) are observed.The concentration of titanium and aluminum catalytic residues in isotactic polystyrene (iPS) samples can be reduced by two methods, i.e., (a) fractionating the polymer and (b) chelating Ti and Al with acetylacetone. The high nucleating ability of iPS samples in the crystallization of iPP has been shown to be due to the polymer (iPS) itself, and not to Ti and Al residues. Apart from iPS, other polymers (low energy surfaces) have also been found to induce transcrystallinity.From a survey of 43 substrate-crystallizing polymer pairs, conclusions have been drawn which are relevant to the following potential factors in heterogeneous nucleation processes: (a) chemical structure, (b) crystallographic unit cell type, (c) lattice parameters, (d) crystallinity of substrate, and (e) surface energy of substrate.
    Additional Material: 5 Ill.
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  • 86
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2429-2434 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In the interference pattern seen in monochromatic light reflected from a craze layer in polystyrene, the bright fringes are of alternating intensity. The phenomenon is explained in terms of a four-beam interference. Apart from the two reflections from the outer surfaces of the craze layer others arise from a thin layer of approximately constant thickness within the craze layer at its median plane. The phenomenon provides independent evidence to support the electron microscopic observations of the microstructure of crazes in polystyrene.
    Additional Material: 5 Ill.
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  • 87
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 43-57 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We describe a new technique for producing fibrous crystals from shear-induced crystallization of polymer solutions and polymer melts. Our technique makes use of a modified version of the 4-Roller apparatus originally developed by G. I. Taylor to study the formation of emulsions. This apparatus generates a planar extensional flow field in which macromolecules are extended more easily than in flow fields with transverse velocity gradients.
    Additional Material: 6 Ill.
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  • 88
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 73-86 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Extrudates of solid linear polyethylene prepared under proper pressure and temperature conditions have a high c axis orientation along the extrusion direction, with lamellar crystals and amorphous layers stacked alternately along the extrusion direction. Kink bands were formed by compressing the oriented extrudate at room temperature along the extrusion direction. Inspection of the kink bands by wide-angle and small-angle x-ray diffraction and electron microscopy revealed that the fiber axis was rotated from the original axis direction by 70-75° and that the lamellar crystals were inclined to the fiber axis in the kink band by 55-60° and stacked nearly parallel to the kink boundary. The superstructural change during the formation of the kink band could not be interpreted in terms of uniform c axis shear alone. In addition to such a mechanism, it was necessary to take into account intermicrofibril and/or intercrystallite slip.
    Additional Material: 11 Ill.
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  • 89
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 87-93 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 5 Ill.
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  • 90
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 127-135 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fracture surfaces of an oriented polystyrene (by stretching 150% at 280°F) show many of the same features observed in the fracture of ordinary polystyrene: craze formation followed by quasi-viscous separation of the craze layer or by quasi-brittle fracture along the craze boundary. In cleavage fracture along the direction of orientation, advance fractures are initiated in flat areas covered, if at all, by an extremely thin layer of craze: the initiation of the “crazeles” fractures appears to arise from the orientation of the molecules rather than the presence of impurity particles.
    Additional Material: 7 Ill.
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  • 91
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 177-202 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Experiments have been carried out on thermal diffusion of macromolecular particles dispersed in various liquids, with the object of checking some predictions of the radiation-pressure theory of Soret effect in liquids and of establishing a method of physical characterization of macromolecules in liquid solutions. The experimental results confirm the importance of the ratio G between thermal conductivity K and (phase) velocity v of high-frequency elastic waves of the materials composing the mixture in determining the thermodiffusive behavior of a liquid solution. We have shown that the migration of the macromolecular component takes place in the same direction in which thermal energy is flowing or opposite to it, depending on whether G of the dispersed particles is smaller or larger relative to the G of the liquid.Another aspect of the same phenomenon may be observed when macroscopic pieces of nonmetallic materials are suspended in a liquid, and heat is made to flow through this solid plunger and the surrounding liquid. The experiments performed with molecular solutions and with macroscopic plungers mutually complement and confirm each other.Anomalous results obtained in the case of solutions of polyvinylpyrrolidone in methanol are also discussed, and the possibility that this might be the consequence of the existence of a marked velocity dispersion in the high-frequency region of the spectrum of thermal waves in both water and methyl alcohol is indicated.Finally the possibility is hinted that thermal diffusion might have been responsible for the phenomena of molecular selection and evolution which ultimately led to the origin of life on our planet.
    Additional Material: 12 Ill.
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  • 92
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 253-262 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By using the model of a randomly coiled chain, a relation is derived describing the equilibrium stress-strain behavior of variously ionized polyelectrolyte gels swollen in solutions of a uni-univalent salt. The effect of the concentration of bound counterions calculated on the basis of the cylindrical model and the effect of the change of length of the statistical chain segment with the change in ionization of the gel on stress-strain, swelling, and potentiometric equilibria is discussed.
    Additional Material: 1 Ill.
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  • 93
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 295-301 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Brillouin light scattering has been used to measure the sound velocities in polystyrene of two different molecular weights. The variation of sound velocity with temperature is related to volumetric expansion of the polymer. Using the thermal expansion data of Fox and Flory we have determined the Grüneisen number, γ, below the glass transition to be 4.4 and 4.3 for low- and high-molecular-weight polystyrenes, respectively, and 5.1 and 5.6 above the glass transition. These numbers compare reasonably well with the value of 3.9 determined by Wada et al. Our measured values are in good agreement with Barker's “bundle of chains” model.
    Additional Material: 2 Ill.
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  • 94
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 339-350 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Different single crystal preparations of polyethylene with (unfractionated) and without (partially fractionated) low molecular weight chains were irradiated at room temperature. G(crosslink) was determined from the gel point. It is shown that in addition to the molecular weight and molecular weight distribution of polymers, G(crosslink) is determined by three more parameters: thickness of crystalline core, amount of amorphous surface layer, and degree of interlamellar contact. Unlike unfractionated polyethylene, partially fractionated polyethylene showed almost 100% gel at about 250 Mrad. To obtain the same amount of gel, unfractionated polyethylene required a much higher dose than that required by partially fractionated polyethylene. Molecular weight distribution of sol fractions of unfractionated and partially fractionated polyethylene was studied by gel permeation chromatography (GPC) and the solubility data analyzed by Charlesby-Pinner plots. It has been shown that the unattainability of 100% gel from unfractionated polyethylene is due to segregation of low molecular weight chains during crystallization which need very high doses for complete gelation.
    Additional Material: 8 Ill.
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  • 95
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The crystal structure of the monomer bis(p-toluene sulfonate) ester of 2,4-hexadiyne-1,6-diol (pT) is conducive from the viewpoint of both the separation distances and molecular configuration, to polymerization, irrespective of whether initiation is thermal, photochemical, or mechanical. The dislocations present in the monomer and polymer structures have been characterized by employing optical microscopic techniques. The slip system (102)[010] is found to be present in both monomer and polymer crystals but the (010)[001] system is found only in the monomer. On this basis a crystal structure for the monomer is proposed based on existing crystallographic information relating to the structure of the polymer. Dislocations are thought, on energetic grounds, to facilitate nucleation of product in the thermal polymerization but have no observable influence on the photoinduced reaction which proceeds homogeneously through the bulk.
    Additional Material: 9 Ill.
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  • 96
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 787-798 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The epitactic behavior of a single chain of polyoxymethylene and of polythiomethylene on alkali halide substrates has been simulated by computing the coulombic, induced dipolar, and dispersion-repulsive potential energies as a function of polymer-substrate geometry. Inspection of the total potential energy surface for a polyoxymethylene chain in a 9/5 helix reveals a favorable alignment in which the chain is parallel to the substrate surface ((001) cleavage plane) with specific positioning along rows of positive charge. This preferential orientation has been found to be independent of lattice matching between the substrate and deposited phase. An identical mode of orientation is predicted for a polyoxymethylene chain and a polythiomethylene chain, both in the 2/1 cis-planar conformation. The theoretical results for polyoxymethylene are in agreement with available experimental evidence, whereas the outcomes of the calculations performed on polythiomethylene should be considered predictive study to be complemented by a future experimental investigation.
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  • 97
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 851-856 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 98
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 863-869 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 99
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 889-899 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 13C NMR configurational assignments are made for an amorphous polystyrene sample examined at 25.2 MHz and 120°C. The assignments are based strictly on a one-parameter Bernoullian fit that was in satisfactory agreement with the nine observed methylene relative intensities. The methylene regions of the 13C NMR spectra of a polystyrene were examined before and after hydrogenation of the side-chain phenyl substituents. It was concluded that ring current effects have influenced the 13C methylene chemical shifts substantially and are limited largely to contributions from adjacent phenyl substituents. In addition, aromatic substituent parameters are reported that can be used in conjunction with the Grant and Paul parameters for calculating chemical shifts in aromatic hydrocarbons and polymers. Finally, it is concluded that free-radical and n-butyllithium-prepared polystyrenes have essentially atactic structures with meso additions favored over racemic additions by approximately 55/45.
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  • 100
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    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1057-1061 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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