Toward Morphology Development and Impact Strength of Co-continuous Supertough Dynamically Vulcanized Rubber Toughened PLA Blends: Effect of Sulfur Content

Abstract In this study, supertough dynamically vulcanized blends (DV) of polylactide (PLA) and acrylonitrile butadiene rubber (NBR) are prepared. Effects of sulfur content on the compatibility, interfacial adhesion, morphology and impact resistance are investigated. NBR presents in spherical droplets dispersed in the PLA phase in absence of sulfur. With addition of sulfur, however, NBR tends to present in a continuous phase formed by numerous microfibril-like elongated vulcanized rubber, whereas the DV with 3 phr sulfur demonstrates a more uniform co-continuous structure. Correspondingly, the DV exhibits a sharp brittle-ductile transition occurs as the sulfur content increases from 1.5 to 2.5 phr, and the DV with 3 phr achieves an impact strength of almost 30 times that of neat PLA. This work aims to illustrate the development of network-like dispersion of vulcanized rubber in PLA-based DVs, and the findings provide a useful guideline in future exploration of PLA-based DVs.