Novel strategy for polymer blend compatibilization: Solid-state shear pulverization

Solid-state shear pulverization (S3P) was used to compatibilize a polypropylene/polystyrene blend without adding premade copolymers or conventional functional groups. S3P is done at temperatures below the melt or glass transition. Polymer pellets or flakes undergo compression and high shear/extensional conditions, resulting in fragmentation/fracture into a fine powder without melting. Depending on S3P conditions, chain scission may occur, yielding highly-reactive free radicals at chain ends. Radical combination at interfaces and in highly-mixed regions may yield block copolymers like those achieved with reactive compatibilization during melt mixing of functionalized polymers.