MORPHOLOGY AND DEFORMATION MECHANISMS OF POLYSTYRENE LOW-DENSITY POLYETHYLENE BLENDS STUDIED BY TEM

The present investigation deals with morphology and deformation mechan isms of the plastic-toughened plastic system composed of a crystalline (low density polyethylene, LDPE) and an amorphous (polystyrene, PS) c omponent. By proper use of a solution-melt procedure of specimen prepa ration for transmission electron microscope (TEM), not only the multip hase structure of the PS/LDPE blends, but also details of the crystall ine morphology of LDPE in the blends have been successfully revealed. Based on the TEM morphological observations of the blends under in-sit u stretching process, the toughness and deformation mechanisms of the blends are explored. It is found that multiple-craze is the main mecha nism of deformation and toughening when LDPE constitutes the dispersed phase, whereas shear-yielding becomes major deformation mode when LDP E forms the continuous phase.