COMPATIBILIZATION OF REFINED COMMINGLED POSTCONSUMER PLASTICS

In attempts to improve the properties of post-consumer commingled plas tics waste a variety of additives that could potentially act as compat ibilizers/impact modifiers were evaluated. The feedstock was represent ative of a model curbside collection program and contained a variety o f polymers, mostly polyethylenes with PET, PP, PVC, etc., in smaller a mounts. The ground mixed plastics were first compounded and melt filte red in a counter-rotating nonintermeshing twin-screw extruder and then combined with different amounts of additives in a corotating intermes hing twin-screw extruder. Additives included unmodified and maleated p olyolefin elastomers and styrene/olefin block copolymers. Blends were analyzed for thermal and mechanical properties, and processability. Th e most effective modifier in terms of impact strength improvement was a styrenic block copolymer with very similar rheological characteristi cs to the commingled plastics matrix. The experimental observations we re interpreted by considering the complex morphological features of th e injection molded multicomponent, multiphase systems. (C) 1994 John W iley & Sons, Inc.