Processing degradation of polypropylene-ethylene copolymer-kaolin composites by a twin-screw extruder

Degradation resulting from the extrusion processing of polypropylene-ethylene kaolin composites (PPE/kaolin) was investigated. Degradation of the polymer matrix was evidenced by the formation of hydroxyl, carbonyl and alkene groups, as detected by Fourier transform infrared spectroscopy measurements. These measurements also confirmed that the filler loading accelerated the degradation process and resulted in scission of high-molecular weight chains. These degradations resulted in significant reductions in the thermal stabilities of the composites, whereas the rheological behaviours and mechanical properties of the composites were strongly influenced by the filler contents rather than by degradation.