The Effect of Core–Shell Ratio of Acrylic Impact Modifier on Toughening PLA

Abstract

ABSTRACT Acrylic impact modifier (ACR), one kind of methyl methacrylate–butyl acrylate copolymer with a core–shell structure, was prepared by seed emulsion polymerization. The weight ratio of core–shell ranges from 85.5/14.5 to 71.9/28.1. Then PLA/ACR blends were prepared with a constant ratio of 80/20. The effect of core–shell ratio of ACR on toughening PLA was investigated. Torque analysis revealed that the torque values of PLA/ACR blends increased with increasing shell content of ACR. The impact strength of PLA/ACR blends reached the highest value of 77.1 kJ m −2 when the core–shell ratio of ACR was 79.2/20.8. Transmission electron microscope (TEM) photographs revealed that ACR was dispersed uniformly in the PLA matrix. Scanning electron microscopy (SEM) suggested that the plastic deformation and cavitations were the major toughening mechanism for the PLA/ACR blends. The shell partition PMMA of ACR was partially miscible with PLA from dynamic mechanical analysis.