Rheological effects of the incorporation of chlorinated polyethylene compatibilizers in HDPE/PVC blend

Small-amplitude oscillatory measurements, creep and recoil experiments, cap illary extrusion flow and shrinkage measurements have been performed to elu cidate the effect of block and random chlorinated polyethylene (CPE) on the rheological properties of a ternary high density polyethylene (HDPE)/poly( vinyl chloride) (PVC)/CPE system. It is observed that the storage modulus, the complex viscosity and the steady state viscosity at low shear nates dec rease when a small amount of CPE is incorporated to 50/50 (wt.) HDPE/PVC bi nary blend. However, at high shear rates, in experiments performed in extru sion flow, the trend is reversed, and the incorporation of CPE to the binar y blend increases viscosity. The high melt elasticity of HDPE is severely r educed when this polymer is mixed with PVC, but when CPE is included as a t hird component, elastic recovery is considerably increased. All these rheol ogical results, which are independent of type (block or random) of CPE used , are explained considering the morphological changes produced by CPE and d uring extrusion flow.