MECHANOCHEMISTRY EFFECTS IN RECYCLED POLYPROPYLENE AND ITS BLENDS DURING SOLID-STATE SHEAR PULVERIZATION (S~3P)

摘要

On-going research focuses on understanding the mechanochemistry during Solid-State Shear Pulverization (S~3P) of recycled polypropylene (PP) and its blends. Free radicals formed during this process act as compatibilizing agents for ordinarily incompatible polyolefin blends. It was observed earlier with Nuclear Magnetic Resonance spectroscopy that each S~3P cycle converts a small portion of polypropylene chains from isotactic to atactic stereoregularity. Small amounts of such atactic chain segments impart additional levels of toughness, which offset, in part, the damage associated with the inevitable chain scission. We determined how many processing cycles S~3P-made recycled PP can endure without significant loss of mechanical properties.