MORPHOLOGY AND TEXTURE OF HIGH-DENSITY POLYETHYLENE-POLYSTYRENE BLENDS DEFORMED BY PLANE-STRAIN COMPRESSION

The blends of high-density polyethylene (HDPE) with atactic polystyren e (PS) were deformed plastically by plane-strain compression in a chan nel die. The samples were deformed up to the true strain 1.8 (compress ion ratio 6) in three temperature regimes: below, near, and above the glass transition temperature of polystyrene component. The morphology and the texture of crystalline component in the deformed blend samples were investigated by means of scanning electron microscopy and wide a ngle X-ray diffraction (pole figures technique). It was found that the deformation process in the blend of immiscible HDPE and PS does not d iffer markedly from the deformation of the one-component system from t he point of view of the deformation mechanisms involved. The crystalli ne textures of the blend samples are qualitatively the same as in the plain HDPE deformed under similar conditions. The active deformation m echanisms are the same in deformation of both the plain HDPE and HDPE/ PS blend, The mechanism identified are crystallographic slips: (100)[0 01], (100)[010], and (010[001] supported by the interlamellar slip. Th e presence of PS in blends modifies to some extent the deformation pro cess and resulting orientation of the crystalline component, of HDPE b y modification of the stress distribution within HDPE matrix around PS inclusions. This influence is much stronger at low deformation temper atures, when PS is in a glassy state, than at temperatures above T-g o f PS. (C) 1996 John Wiley & Sons, Inc.