Effect of matrix chain entanglement on toughening mechanism evolution of acrylic impact modifier toughened methyl methacrylate-N-phenylmaleimide copolymers

Abstract

The toughening mechanism evolution of acrylic impact modifier (AIM) toughened methyl methacrylate-N-phenylmaleimide copolymers (PMMA-PMI) was investigated in terms of matrix chain entanglement density (νe), especially within the range of matrix νe ≈ 0.1 mmol/cm3. After respectively blended the PMMA-PMI having designed νe with the same content preformed AIM, it was showed that the notched impact strength of the blends increase with PMMA-PMI νe enhancement. The morphological analyses revealed that the extent of shear yielding gradually enlarged when matrix νe is higher than 0.1061 mmol/cm3. Whereas, in the AIM/PMMA-PMI blend with lower matrix νe, the toughening mechanism transformed into matrix crazing triggered by PBA cavitation. The results suggest that the response of the matrix with different νe to the rubber particle cavitation dominate toughening mechanism and mechanical performance of AIM/PMMA-PMI blends, and it is believed that matrix νe is an inherent factor to toughening mechanism evolution.