AbstractThe present investigation deals with amorphous polystyrene crazing behavior at both the molecular and macroscopic levels. The nature of the amorphous state is considered from the perspective of statistical fluctuation theory, especially when a mechanical force field is acting on the polymer. Past crazing studies have rather fully described the phenomenological behavior. However, these studies did not generate a fundamental molecular explanation of crazing. We now suggest a molecular approach based on the density and density distribution of physical entanglements between polymer chains as a function of molecular weight. This approach permits the molecular entanglement concept and the phenomenological parameters such as stresses and temperatures associated with crazing to be related through the use of fluctuation theory. Two fundamental results are obtained and specifically demonstrated for polystyrene. First, an accurate theoretical prediction of the volume associated with microvoid formation is explicitly determined. Second, the dependence of the number of crazes on molecular weight is also shown.
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