EFFECT OF E P RATIO AND VA CONTENT ON FLOW BEHAVIOR OF EPDM AND EVA BLENDS/

The effect of E/P ratio of EPDM rubber and VA content of EVA copolymer on the flow behavior along with the extrudate morphology of EVA and E PDM blends have been studied as a function of shear-rate and processin g temperature. High E/P ratio EPDM rubber and low VA content EVA rende r high viscosities to the blend within the temperature range studied. The same trends hold true for extrudate swell. Stored elastic energy a nd relaxation time are higher for high E/P ratio EPDM and low VA conte nt EVA. However, compositions with low E / P ratio EPDM exhibit higher shear modulus. At a particular blend composition these rheological pa rameters show a change in their pattern. Melt fracture occurs to a lar ger extent for the high E / P ratio EPDM in its blend with low VA cont ent EVA. (C) 1994 John Wiley & Sons, Inc.