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  • 11
    Electronic Resource
    Electronic Resource
    Spectroscopic method of measuring the stresses at stress raisers in polymers (1970)
    Springer
    Mechanics of composite materials 6 (1970), S. 156-159 
    Details
    ISSN: 1573-8922
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A method of measuring the mechanical stresses near stress raisers from the frequency shift of the IR absorption bands is proposed. The stresses at the edge of an ellipse as determined by IR spectroscopy, from the birefringence, and by theoretical calculation are compared. It is shown that the results coincide. The stress near the tip of a crack has been measured by the IR spectroscopy technique. It is shown that these stresses may be ten or more times greater than the external tensile stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00860468
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  • 12
    Electronic Resource
    Electronic Resource
    An infrared spectroscopic study of the breakdown of polymers under load (1970)
    Springer
    Mechanics of composite materials 6 (1970), S. 369-372 
    Details
    ISSN: 1573-8922
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract It has been found that when a uniaxial tension is applied to highly oriented polymer films of polypropylene, polyvinyl alcohol, or polyethylene, an increase in the intensity of the absorption bands corresponding to the vibrations of the C=O carbonyl groups is observed. These groups are produced by the oxidation of the free radicals formed on the rupture of the chemical bonds under the influence of mechanical stress. The composition of the products has been studied, and their concentration has been estimated. Curves giving the accumulation of C=O groups with time at constant load and with increase in stress for a fixed period of time under load have been studied. It is suggested that the rate of accumulation of C=O groups in both cases is determined chiefly by the rate of rupture of the molecular chains under load.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00858195
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  • 13
    Electronic Resource
    Electronic Resource
    Molecular mechanism of oriented crystalline polymers (1973)
    Springer
    Mechanics of composite materials 9 (1973), S. 517-520 
    Details
    ISSN: 1573-8922
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract It is shown with reference to linear polyethylene that the deformation of an oriented crystalline polymer takes place as a result of elongation of the coiled parts of the macromolecules in the amorphous zones owing to conversion of gauche into extended trans isomers. The decrease in coiled isomer content when the specimen is deformed by approximately 5% is accompanied by a small number of chemical bond breakages. Repeat deformation by the same amount does not result in any additional breakage of polymer chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00855886
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  • 14
    Electronic Resource
    Electronic Resource
    Molecular destruction of polymers at the apex of a major crack (1972)
    Springer
    Mechanics of composite materials 8 (1972), S. 536-539 
    Details
    ISSN: 1573-8922
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We employed infrared spectroscopy and infrared spectroscopy of deflected total internal reflection to study the rupture of polymer macromolecular chains (polyethylene and polypropylene) at the apex of a growing crack. It was shown that the break concentration at the crack surface is of the same order of magnitude as the total concentration of chemical bonds in the polymer; molecular rupture occurs not only at the apex itself but also at some distance from it. The dependence of the break concentration on the distance from the crack apex was measured. The observed patterns were related to the experimentally determined external-load distribution function for individual chemical bonds near the crack apex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00855578
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  • 15
    Electronic Resource
    Electronic Resource
    Influence of intermolecular interaction on kinetics of conformational transitions in poly-m-phenyleneisophthalamide (1985)
    Springer
    Journal of applied spectroscopy 43 (1985), S. 891-895 
    Details
    ISSN: 1573-8647
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00660770
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  • 16
    Electronic Resource
    Electronic Resource
    Determining the content of hydrogen dissolved in quartz glass using the methods of Raman scattering and mass spectrometry (1987)
    Springer
    Journal of applied spectroscopy 46 (1987), S. 632-635 
    Details
    ISSN: 1573-8647
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00661243
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  • 17
    Electronic Resource
    Electronic Resource
    Molecular orientation and the tensile strength of polystyrene (1969)
    Springer
    Mechanics of composite materials 5 (1969), S. 531-534 
    Details
    ISSN: 1573-8922
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The tensile strengths of uniaxially oriented polystyrene films with molecular orientation determined by IR spectroscopy are compared. Two different orientation methods involving different time and temperature regimes are employed. It is found that the tensile strength is a unique function of the degree of orientation of the molecular segments of the polystyrene carbon chain irrespective of the means used to orient the specimens and increases linearly with increase in the degree of molecular orientation of the polymer. The experimental dependence is in satisfactory agreement with the results of a theoretical analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00857230
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  • 18
    Electronic Resource
    Electronic Resource
    Mechanochemical reactions in oriented polymers (1971)
    Springer
    Mechanics of composite materials 7 (1971), S. 347-350 
    Details
    ISSN: 1573-8922
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Polymer orientation is accompanied by the formation of new chemical groupings, which may be taken as evidence of mechanochemical reactions and degradation of the macromolecules. The composition and concentration of the compounds formed have been investigated. The accumulation of new chemical groups has been recorded as a function of elongation and as a function of experimental temperature at a fixed elongation. The change in the molecular weight of polyethylene associated with orientation has been estimated from the infrared spectroscopy data and from the intrinsic viscosity in decalin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00854784
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  • 19
    Electronic Resource
    Electronic Resource
    Overstressed interatomic bonds in stressed polymers (1975)
    Springer
    International journal of fracture 11 (1975), S. 789-801 
    Details
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Infrared (IR) spectroscopy is used to find how the applied mechanical stress imposed upon a sample is distributed among the interatomic bonds. The distribution is highly heterogeneous: 80–95% of the bond population experience stresses close to the applied stress, the stress on the rest of the bond population varies over a wide range and reaches 1000–2000 kg/mm2. The overstressed interatomic bonds lie in the amorphous regions of the polymer and are oriented in the direction of the mechanical force. The maximum stress on interatomic bonds is determined by the magnitude of the breaking stress on them. The breaking stress is shown to be a function of the applied stress, time, and temperature. This dependence is due to scission of stressed bonds induced by thermal fluctuations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012897
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  • 20
    Electronic Resource
    Electronic Resource
    Kinetic micromechanics of polymer fracture (1975)
    Springer
    International journal of fracture 11 (1975), S. 803-815 
    Details
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Direct physical methods were used for studying molecular fracture in stressed polymers. The macromolecular ruptures were detected by electron paramagnetic resonance, infrared spectroscopy, and mass spectrometry. Nucleation of incipient submicrocracks was registered by small-angle X-ray scattering and light scattering. All methods were used to study fracture kinetics at different stresses and temperatures. The thermal fluctuation nature of microruptures is verified and the activation energy for the elementary events of polymeric fracture is estimated. This energy coincides with the activation energy for macrorupture evaluated in the study of the lifetime of polymers. Chain chemical reactions of stresses macromolecules disruption are proved to take part in formation of incipient cracks. The main features of the micromechanics of polymer fracture are listed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012898
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