STUDY ON THE POLYPROPYLENE HIGH DENSITY POLYETHYLENE/STYRENE-BUTADIENE-STYRENE BLOCK-COPOLYMER TERNARY BLENDS .2. THE EFFECT OF PROCESSING ON THE PROPERTIES AND MORPHOLOGY OF POLYPROPYLENE/HIGH DENSITY POLYETHYLENE/STYRENE-BUTADIENE-STYRENE TERNARY BLENDS/

It has been shown that the impact strength of non-compatible polymer b lends is closely related to the number, shape and morphology of the di spersed phase particles. The general condition for toughening is that the inter-particle distance must be smaller than a critical value T-c (Critical Inter-Particle Distance). Thus a sharp brittle-ductile trans ition would occur as T becomes smaller than T-c. This has been applied to interpret the relationships of the impact strength of the blends w ith their respective phase morphology, particle diameter and elastomer volume fraction. The objective of this study is to examine the effect of various blending processes on the morphology of the rubber particl es in the PP/HDPE/SBS ternary blends, The relation of the impact stren gth of PP ternary blends with the SBS particle diameter has been inves tigated. It is found that the morphology of the SBS dispersed phase pa rticles is closely related to the mechanical properties of the PP tern ary blends and it is very much dependent upon the processing parameter s of the blends.