THE RELATIONSHIPS BETWEEN POLYMERS AND GLASS TRANSITION TEMPERATURES
Rept. for Jun 1963-May 1964
AMERICAN CYANAMID CO STAMFORD CT
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The parameter T sub 0 was investigated as an indicator of glass formation in simple liquids for which viscosity and density have been published at various temperatures T. It was found that the Gibbs-DiMarzio theory correctly predicts the values of T sub 0 of the n-alkanes with a stiffness energy of 490 cal.mole. The predicted T sub 0 for polyethylene is 129K, which corresponds to a wellknown transition. A detailed study of steric factors in polymers is expected to lead to methods of predicting the stiffness energy and hence T sub 0. A free volume theory was developed which accounts satisfactorily for the change in viscosity with external pressure, and which separates the phenomenological effects of temperature and pressure from the structural and molecular factors involved in flow behavior. The adjustable constants have not yet been correlated with chemical structure, however.
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