DEVOLATILIZATION - A CRITICAL SEQUENTIAL OPERATION FOR IN-SITU COMPATIBILIZATION OF IMMISCIBLE POLYMER BLENDS BY ONE-STEP REACTIVE EXTRUSION

The main objective of this study was to show that an efficient removal of residual monomers is very important for in situ compatibilization of immiscible polymer blends by one step reactive extrusion, One-step reactive extrusion means that when compatibilizing two immiscible poly mers with one polymer containing potential functional groups and the o ther being chemically inert with respect to these functional groups, f unctionalization of the chemically inert polymer and its subsequent in terfacial reaction with the functional polymer are accomplished in a s ingle extrusion process. Two model blend systems were chosen: polyprop ylene/poly(butylene terephthalate) (PP/PBT) and high density polyethyl ene/polyamide 6 (HDPE/PA6). A co-rotating intermeshing twin screw extr uder was used to process these blends. Glycidyl methacrylate (OMA) and maleic anhydride (MA) were used to functionalize PP and HDPE, respect ively. Results showed that the mechanical properties of both blends In terms of elongation at break and impact strength were improved to a m uch greater extent with up-stream devolatilization compared with down- stream devolatilization.