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  • Polymer and Materials Science  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    Heat and entropy of fusion of polypropylene (1964)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 2723-2730 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: There are wide discrepancies in the literature values for the heat of fusion (ΔHu) of isotactic polypropylene. A study was therefore made of the variables affecting ΔHu as determined by differential thermal analysis. The results of this study show ΔHu for 100% “crystalline” polypropylene to be 2400 cal./mole repeating unit with 2σ = 300. The entropy of fusion is 5.4 e.u./repeating unit (2σ = 0.3). Thermal history, potential errors in sample-sensor contact as well as uncertainties in x-ray analysis for per cent crystallinity are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1964.070080618
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Ethylene-propylene copolymers: Degree of crystallinity and compositionTaken in part from a paper presented at the 1969 Gordon Conference on Elastomers, Colby College, New London, New Hampshire, July 28-August 1, 1969. (1971)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 9 (1971), S. 127-142 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: X-ray, differential scanning calorimeter, and density measurements of the degree of crystallinity have been made on ethylene - propylene copolymers which range in composition from 60 to 100 mole-% ethylene. At 23°C the degree of crystallinity was found to vary from zero to approximately 75 wt-% in a regular manner with composition. A systematic difference exists between the x-ray and heat of fusion measurements if a simple two-phase model is assumed in order to calculate the per cent crystallinity from heats of fusion. The apparent heat of fusion of the crystalline fraction detected by the x-ray method is as low as 30 cal/g. This discrepancy increases with comonomer content. It is suggested that large surface or defect energies are present. The broad melting behavior of the samples is also consistent with such a description of the system.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1971.160090109
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Crystalline polymers of bis(β-chloroethyl) vinylphosphonate (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 4 (1966), S. 2423-2427 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of bis(β-chloroethyl) vinylphosphonate to a crystalline solid was carried out with a Ziegler-Natta catalyst. A confirmation of the crystalline nature of the polymers was carried out by x-ray diffraction. The polymers would not melt even at temperatures up to 620°C., but instead began to char. However, they were soluble in dimethylformamide and acrylonitrile.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1966.150041007
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    Paper (German National Licenses)
    Fulltext
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