IMPACT AND TENSILE PROPERTIES OF SEBS COPOLYMER COMPATIBILIZED PS HDPE BLENDS/

In this study, polystyrene-hydrogenated polybutadiene-polystyrene (SEB S) triblock copolymer was used as a compatibilizer for the blends of p olystyrene (PS) and high-density polyethylene (HDPE). The morphology a nd static mechanical and impact properties of the blends were investig ated by means of scanning electron microscopy, uniaxial tension, and i nstrumented falling-weight impact measurements. Tensile tests showed t hat the yield strength of the PS/HDPE/SEBS blends decreases considerab ly with increasing HDPE content. However, the elongation at break of t he blends tended to increase significantly with increasing HDPE conten t. The excellent tensile ductility of the HDPE-rich blends resulted fr om shield yielding of the matrix. Charpy impact measurements indicated that the impact strength of the blends increases slowly with HDPE con tent up to 50 wt %; thereafter, it increases sharply with increasing H DPE content. The impact energy of the HDPE-rich blends exceeded that o f pure HDPE, implying that the HDPE polymer can be further toughened b y the incorporation of brittle PS minor phase in the presence of SEES compatibilizer. The correlation between the impact property and morpho logy of the blends is discussed. (C) 1998 John Wiley & Sons, Inc.