PLASTIC-DEFORMATION OF POLYMER BLENDS WITH CRYSTALLIZABLE COMPONENTS

The application of polymer blends depends mostly on their high ability to plastic deformation. Usually the studies of plastic deformation be havior include only the stress-deformation relationship and investigat ion of changes of morphology of the blends on the size level of inclus ions. The energy absorption is also often considered. The presented, m ore rigorous, approach to plastic deformation of polymer blends contai ning a crystallizable component involves the studies of crystal plasti city and associated deformation of the amorphous phase. Plastic deform ation of blends containing high-density polyethylene and isotactic pol y(propylene) with other components were studied in two modes of deform ation: 1. that avoids internal cavitation and 2. in tension with inten se voiding. When no internal cavitation was involved, the plastic defo rmation was crystallographic in nature while the amorphous phase defor med in a manner to accommodate for the rotation and slips of the cryst alline phase. Also the plastic deformation associated with intense voi ding leads to a preferred orientation of certain crystallographic plan es containing macromolecular chains which strongly suggests that the l eading mechanisms in plastic deformation of blends are of crystallogra phic nature. The plastic deformation behavior depends very much on the glass transition of the amorphous component of the blend.