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  • Polymer and Materials Science  (15)
  • Analytical Chemistry and Spectroscopy  (8)
  • 1970-1974  (23)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Extension of elastic liquids: Polyisobutylene (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1-17 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An apparatus is described and a method discussed for determining the rheological characteristics of elastic liquids during extension at constant rates of deformation and extension. The material studied was polyisobutylene of molecular weight 7 × 104. At low constant deformation rates steady-flow regimes were achieved, with corresponding equilibrium high elastic strains. A detailed study has been made of the process of attainment of steady-flow regimes and it is shown that before steady flow is reached the curve of longitudinal viscosity versus strain passes through a maximum. As the rate of deformation rises, the strains at which steady-state flow regimes are achieved increase, and the time required to reach these regimes decreases. Qualitatively this occurs in the same way as upon shear. The dependence of equilibrium high-elastic strains (under steady-flow regimes) on the rate of deformation has been determined. At steady-flow regimes the stress depends linearly on the rate of deformation at low values of the stress. Under such conditions Trouton's formula is valid. At constant rates of extension the stress versus time curve passes through a maximum which becomes higher with increasing extension rates.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080101
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  • 2
    Electronic Resource
    Electronic Resource
    Investigation of cooperative kinetics on reactions of functional groups on polymer chains (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 769-777 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of aminolysis of 1,2;3,4-meso-erythritol dicarbonate and 1,2;3,4;5,6-mannitol, sorbitol, and dulcitol tricarbonates by n-butylamine in dimethylformamide solution was investigated. The dicarbonate and tricarbonates are considered respectively as models of dyads and triads in the poly(vinylene carbonate) chain. The theoretical kinetic curves for the dimer and the trimers were calculated by solution of kinetic equations and close agreement with experiment was obtained. A version of the Monte-Carlo method was developed to provide a model for the reaction process by a computer calculation including the neighboring group effect in enhancing reactivity. The theoretical curve for a trimer coincides with the experimental one. These results confirm the accelerating influence of the unreacted neighboring groups. For the polymeric chain the experimental and calculated curves deviate for conversions beyond 10%. This indicates an additional polymer effect, which is as yet unexplained.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090501
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  • 3
    Electronic Resource
    Electronic Resource
    Viscoelastic and relaxation properties of a polystyrene melt in axial extension (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 657-678 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: On axial extension of polymer melts at constant deformation rates, the development of high-elastic deformation is of predominant importance during the initial period. High-elastic deformation is accompanied by a rise in viscosity and in the modulus of high-elasticity and by retardation of the relaxation processes in the region of large relaxation times. At relatively low deformation rates, the rise in viscosity and high-elasticity modulus and the retardation of relaxation processes may give way to a decrease in viscosity and high-elasticity modulus and acceleration of relaxation processes, so that stationary flow regimes are attained. The transition from strain regimes with increasing viscosity and modulus of high elasticity to those with a decrease of these quantities corresponds to an increase in the rate of accumulation of irreversible deformation. Accordingly, a competing influence due to the orientation effect and to destruction of the network of intermolecular bonds becomes evident while stationary flow is being attained. The orientation effect must be responsible for the retardation of the relaxation processes, whereas rupture of the intermolecular network bonds results in structural relaxation accelerating relaxation processes. In contrast to shearing, during extension the orientation effect is of predominant importance. Hence in stationary flow regimes the viscosity may not only remain independent of the rate of strain, but even increase with it. In this case the contribution of the large relaxation times to the relaxation spectrum increases with increasing stress in stationary flow regimes. The fact that the longitudinal viscosity and the modulus of high elasticity are independent of the stress in stationary flow regimes does not guarantee linearity of the mechanical properties of the polymer in the prestationary stage of deformation when complex changes occur in its relaxation characteristics. At high deformation rates the viscosity and the modulus of high elasticity keep rising with increasing deformation until rupture occurs. Determination of the strength of polystyrene samples vitrified after extension showed that it is due not to the entire degree of extension, but only to the value of accumulated high-elastic deformation. The strength of the vitrified samples is to a first approximation independent of the rate at which the melt was extended.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080501
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  • 4
    Electronic Resource
    Electronic Resource
    Normal vibrations of α-glycylglycine (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2091-2098 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A complete normal coordinate analysis, infrared absorption, and inelastic neutron scattering studies on α-glycylglycine are reported. A Urey-Bradley force field which is also valid for N-deuterated sample is obtained. Assignments in the low-frequency region are based on inelastic neutron spectrum obtained in one phonon and cubic approximation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111009
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  • 5
    Electronic Resource
    Electronic Resource
    Vibrational spectrum of cyclic tetra-L-alanine (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2099-2108 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A normal coordinate analysis for cyclic tetra-L-alanine molecule is reported. A comparison of amide modes and other low-frequency vibrations sensitive to conformational changes is made with those in poly-L-alanine. Intramolecular coupling coefficients are calculated using perturbation treatment.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111010
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  • 6
    Electronic Resource
    Electronic Resource
    Vibrational analysis and dispersion curves of poly-L-hydroxyproline chain (1974)
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 1965-1973 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dispersion curves and frequency distribution for poly-L-hydroxyproline (PLHP) chain were obtained using Wilson's GF matrix method as modified by Higgs. These are compared with those of poly-L-proline II and polyglycine II, which also have three-fold screw symmetry. Ring and skeletal modes characteristic of PLHP are identified and the assignments of observed infrared and Raman frequencies are reported. Urey-Bradley force constants were evaluated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1974.360131004
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  • 7
    Electronic Resource
    Electronic Resource
    Vibrational spectra and dispersion curves of poly-L-proline II chain (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 1377-1385 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using Wilson's GF-matrix method as modified by Higgs for infinite helical polymers, dispersion curves and the frequency distribution function have been calculated for poly-L-proline II chain. Infrared spectrum is obtained and a Urey-Bradley force field, which provides best fit with the observed frequencies, is evaluated. The result are discussed from the viewpoint of the conformational characteristics of forms I and II.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120613
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  • 8
    Electronic Resource
    Electronic Resource
    Rheological properties of anisotropic poly(para-benzamide) solutions (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 12 (1974), S. 1753-1770 
    Details
    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 made of the viscous properties of poly(para-benzamide) (PBA) solutions in dimethyl acetamide, which undergo a transition from an isotopic to an anisotropic (liquid-crystal) state at a definite concentration C*. The polymer solutions behave in many respects (as regards the concentration and temperature dependence of viscosity, etc.) like solutions of low molecular weight compounds forming a liquid crystal phase, although the transitions are less pronounced in the polymer solutions owing to their polydispersity. It is shown that the viscometric method, being extremely sensitive to C*, is convenient for determining phase diagrams of anisotropic polymer solutions. The values of C* as related to the molecular weight of PBA have been determined, and a general criterion for transition from isotropic to anisotropic solutions established; the latter has the form (CM̄)* ≈ 1.3 × 105 at 20°C. This criterion is in line with the condition for the formation of the liquid-crystal structure in a dispersion of rodlike particles as proposed by Flory.Generalized concentration dependences of viscosity have been plotted by reducing concentration to C* and viscosity, to the maximum viscosity at the phase transition point. In investigating the flow properties of PBA solutions we revealed the existence of a yield point in the range of low shear stresses, and an intersection of the flow curves of solutions of different concentration at high shear stresses, which excludes a generalized representation of the flow curves in reduced ordinary-type coordinates.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.180120903
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  • 9
    Electronic Resource
    Electronic Resource
    Spectroscopic studies of Lewis acid-base complexes. III: Vibrational frequencies, assignments and normal coordinate analyses for isotopic varieties of phosphine borane and trifluorophosphine borane (1974)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 2 (1974), S. 175-192 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Vibrational spectra of the two Lewis complexes, phosphine borane, PH3BH3, and trifluoro-phosphine borane, PF3BH3, have been investigated for several isotopic species preserving C3v symmetry. New assignments are proposed and substantiated by normal coordinate analyses formulated in the compliance constant basis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250020208
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  • 10
    Electronic Resource
    Electronic Resource
    Reduction of composite NMR spectra by using an analog computerPaper presented to the American Chemical Society, Division of Rubber Chemistry, Symposium on Use of Computers in the Rubber Industry, Washington, D. C., May 5-8, 1970. (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 345-362 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analog computer program has been devised to resolve complex composite curves such as might be encountered in various forms of spectroscopy or chromatography. Seven Gaussian or Lorentzian curves, or any combination of seven curves, can be used and displayed simultaneously to resolve the composite curves. Various degrees of skew and truncation, as well as slanted and curved baselines, can be introduced. The peak amplitude, width and position can be determined from potentiometer settings. The integrated relative area of each of the peaks is read out on a digital voltmeter with a reproducibility of about ±0.1%. The utility of the technique is demonstrated by resolving highly overlapped peaks in NMR spectra of butadiene-styrene copolymers. It is necessary to use as many as eight curves to resolve the styrene aromatic proton resonance. This analysis yields styrene-centered distributions and styrene sequence distributions from the NMR spectra of butadiene-styrene copolymers. In addition, it is shown that a distinction can be made between short styrene sequences, which contain two and three styrene units, and long styrene sequences, which include all sequences longer than three units.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.150090210
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