REGENERATION OF HIGHLY DISPERSE STRUCTURE IN CRAZED POLYMERS

Repeated drawing in air of the crazed polymers was shown to regenerate microfibrillar structure of the crazes, which were formed upon first drawing of polymer films in liquid environments and collapsed upon sub sequent drying. As a result of such regeneration, the resultant materi al showed a well-developed inner surface in crazes and high gas permea bility. Such regenerated porous materials can be used as components in gas-selective membranes, filters, etc. In the case of repeated drawin g of the crazed polymers, an increase in strength of the bulk polymer in between the crazes and a decrease in post-yield stress of repeated drawing were shown to favor the development of highly porous and dispe rse structure. The properties of the crazed polymers as realized in th e course of the repeated drawing were controlled by the existence of a dsorption layers in the collapsed craze structure.