MECHANICAL PROPERTIES OF SEMICRYSTALLINE POLYMERS REGARDED AS COMPOSITE MATERIALS.

Although the concept of densely packed, interpenetrating, randomly coiled molecules provides a substantial basis for the interpretation of bulk properties of amorphous polymeric solids, this concept must be augmented with additional tools to describe the consequences of local heterogeneities and orientations upon the observed properties. In this paper, crystalline polymers are hypothesised to behave, with respect to their mechanical properties, as a multiphase composite solid. Experimental model systems are employed to illustrate this concept. Illustrative calculations are then presented which employ the micromechanics and macromechanics available in composite theory to develop a property-structure calculation for the influence of supermolecular structures on stiffness properties. Additional comments are then made upon the permissible theoretical stiffness of highly oriented polymer chains. Refs