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  • Physics  (107)
  • EARTH RESOURCES AND REMOTE SENSING  (97)
  • SPACE SCIENCES  (76)
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  • 1
    Electronic Resource
    Electronic Resource
    Effect of birefringence on low-angle light-scattering patterns from oriented polymer films (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 7 (1969), S. 271-278 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of birefringence of a polymer film upon its photographic light-scattering pattern is considered for the case of a single, anisotropic, two-dimensional spherulite imbedded in a birefringent matrix. It is shown that for the case of a polarizer and analyzer crossed at +45° and -45° to the analyzer, the scattering pattern is modified in a manner agreeing with experimental observation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.160070202
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  • 2
    Electronic Resource
    Electronic Resource
    Birefringence and dichroism of rubbery copolymers (1969)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 7 (1969), S. 2115-2138 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Kuhn-Grün theory for the birefringence and dichroism of rubbery polymers is extended to the case of copolymers consisting of two or more statistical segments of differing lengths. It is shown that the previous equations are applicable provided that the anisotropy of polarizabilities and absorptions are replaced with suitable averages in which the segment anisotropies are weighted by the squares of their segment lengths. This indicates that the stress-optical coefficient will not generally vary linearly with composition. The orientation measured from the dichroism of bands arising from different segments will be different.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1969.160071212
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  • 3
    Electronic Resource
    Electronic Resource
    Scattering of light by deformed three-dimensional spherulites (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 295-311 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A theoretical calculation of the Hv light-scattering patterns for deformed three-dimensional spherulites is presented. Affine deformation is assumed. The optic axis of the scattering element is allowed to lie at an arbitrary angle ß to the radius which is permitted to change in the course of the deformation in a manner that may depend upon the angular location in the spherulite. The consequences of twisting of the optic axis about the spherulite radius are also explored.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090206
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  • 4
    Electronic Resource
    Electronic Resource
    Optical studies of the stress-induced crystallization of rubber (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1-30 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The low-angle light scattering by films of stretched natural and synthetic rubbers was investigated. Intense Vv scattering is found under conditions when crystallization occurs which is characteristic of the scattering from aggregates of dimensions comparable with the wavelength of visible light. These were identified with the γ fibrils described by Andrews. The dependence of scattering was studied as a function of light polarization direction, orientation direction, elongation, temperature, degree of swelling, type of swelling liquid, and degree of crosslinking. It was concluded that the scattering unit consists of an assembly of crystals with their chain axes parallel to the stretching direction, but (in the case of natural rubber at high elongations) with the fibril axis at a slight angle to the stretching direction. The scattering is not affected much by swelling but is decreased upon increasing the temperature. Upon recooling the scattering returns, but does so over several hours, indicating that much of the scattering arises from secondary crystallization.
    Additional Material: 23 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060101
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of birefringence on low-angle light-scattering patterns from oriented polymer films. II (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 489-497 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A quantitative theoretical calculation is made of the effect of birefringence of the surrounding medium on the light-scattering pattern from a two-dimensional anisotropic spherulite. The calculated modification of the light-scattering pattern is in accord with the prediction previously made on the basis of qualitative considerations and model experiments.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080401
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  • 6
    Electronic Resource
    Electronic Resource
    Scattering of light by disordered spherulites (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1137-1157 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The scattering of light by a two-dimensional spherulite of radius R is calculated when there is disorder of optic axis orientation with respect to the radius. Special cases are considered when (1) the disorder occurs in the radial direction only, (2) the disorder occurs in the angular direction only, (3) there is combined radial and angular disorder, and (4) the optic axis makes a constant angle with the radius but there is disorder in the twist angle about the axis. In all of these calculations, a correlation function for disorder is defined and the scattering pattern depends on the ratio of the associated correlation distance to the size of the spherulite. With decreasing correlation distance, the azimuthal dependence of the scattering becomes less and there is a change in the variation of scattered intensity with scattering angles in a manner dependent upon the type of disorder.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080709
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  • 7
    Electronic Resource
    Electronic Resource
    Scattering of light by films having nonrandom orientation fluctuations. II (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1127-1136 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The theory for scattering of light from films in which the orientation correlation between two scattering elements depends upon the angle β between the optic axes and the vector connecting the two elements is extended. A delta-function type dependence is assumed in which the correlation is strongest when β equals some preferred value β0. Calculated results of scattered intensities are shown to be similar to experimental observations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080708
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  • 8
    Electronic Resource
    Electronic Resource
    Time-temperature superposition of the dynamic birefringence of polyethylene (1967)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1079-1086 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dynamic strain-optical coefficient of low-density polyethylene is found to decrease with increasing frequency and increase with increasing temperature (at temperatures up to 60°C.). It is found that a series of curves representing the real, K′, and imaginary, K″, parts of the frequency variation of the strain-optical coefficient obtained at various temperatures up to 60°C. may be superposed by translation along the frequency axis. The temperature dependence of the shift factor corresponds to an Arrhenius type equation with an activation energy of the order of 25 kcal./mole. This may be compared with the similar value obtained by Takayanagi for the αc′ mechanical loss and with the dynamic x-ray diffraction values reported by Kawaguchi et al., but is somewhat lower than the value of 34 kcal./mole reported by Onogi et al. from birefringence relaxation studies. Takayanagi has ascribed the αc′ peak to cooperative motion of crystalline and amorphous regions of the sort that might be involved in the suggested sliding of lamellae over each other. At temperatures higher than 80°C., horizontal superposition is not possible.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1967.160050608
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  • 9
    Electronic Resource
    Electronic Resource
    Some studies of the crystallization of polychlorotrifluoroethylene copolymer films (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 31-61 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A fluorocarbon copolymer of chlorotrifluoroethylene (96%) and vinylidene fluoride has been isothermally crystallized and the quenched films analyzed by the light microscope, photographic light-scattering, and density measurements. Above a supercooling of 79°C., homogeneous nucleation dominates, giving a morphology that appears to be that of a twisted ribbon. At supercoolings below 79°C., heterogeneous nucleation dominates and leads to spherulitic morphology. Sheaf or rodlike morphology occurs at very low supercoolings. Crystallization rates determined from density measurements at room temperature indicate maximum rate due to heterogeneous nucleation occurring at a supercooling greater than 79°C., but the temperature for maximum rate cannot be identified because of the transition to homogeneous nucleation which causes a discontinuity in the rate versus temperature curve. Superposability of crystallization isotherms constructed from density values are inconsistent with the large melting point lowering from that of polychlorotrifluoroethylene for this copolymer. However, this may be explained by the presence of a different crystal system for each monomer in the copolymer.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060102
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  • 10
    Electronic Resource
    Electronic Resource
    Acetylation of cellulose I and II studied by limiting viscosity and X-ray diffractionPaper presented in part at 153rd meeting of the American Chemical Society in Miami, Florida, April, 1967. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 745-773 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When cellulose triacetates and some hydrolyzed acetates are boiled in 2.5N hydrochloric acid there is no residue. Under the same conditions cellulose is hydrolyzed, and a residue is obtained with a limiting viscosity that is related to the average length of the cellulose crystallites. These findings are combined to develop a method for studying the progress of acetylation through the amorphous portion of cellulose and into the crystallites, and to investigate the relative reactivities of cellulose I and cellulose II. Acetates were made from cotton and wood cellulose by a “fibrous” (heterogeneous) esterification involving sulfoacetic acid or perchloric acid catalyst in acetic acid-acetic anhydride; the final acetyl contents (10-41%) were attained by stopping the reaction at various points short of the triester (rather than by hydrolyzing a triester). When these acetates were boiled in 2.5N HCI they did not disappear completely, and the residues were cellulose I, indicating that cellulose acetate had been removed. With increasing acetyl the yield of residue decreased, and beyond about 33% acetyl the viscosity and x-ray measurements showed that the length and width of the crystallites decreased. However, when a nonsolvent such as toluene was added to the acetylation medium, the limiting viscosity did not change over the same acetyl range (up to 40%). Samples of varying acetyl values were taken during a regular acetylation of cotton linters in a mixer with sulfuric acid catalyst. X-ray studies of the residues obtained by boiling the acetates in 2.5N HCI revealed the presence of unreacted cellulose I even after 40% acetyl had been reached. This explains why the manufacture of cellulose esters from cellulose I requires complete esterification before they are hydrolyzed to the desired acetyl level. It was shown that there is a distinct difference between the acetylation reactivity of cellulose I and cellulose II. This indicates the importance of avoiding cellulose II formation during the refinement of cellulose for the manufacture of cellulose acetate in a process involving activation with acetic acid.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060410
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