Role of Dicumyl Peroxide on Toughening PLLA via Dynamic Vulcanization

Our previous work demonstrated that the toughness of PLLA could be improved dramatically by dynamic vulcanizing blends of PLLA/NBR with dicumyl peroxide (DCP) as a cross-link agent. Herein, to reveal the toughening mechanism of DCP on the PLLA/NBR thermoplastic vulcanizates (TPVs), the distribution of DCP in the PLLA matrix and NBR phase was modulated by changing feeding procedures. The cross-link density of NBR, phase morphology, and mechanical properties of PLLA/NBR–TPVs were investigated thoroughly. It was found that impact toughness of the blends is dependent on the distribution of DCP, while the tensile properties almost keep unchanged with alteration of the feeding procedure. PLLA/NBR–TPV prepared by premixing DCP with PLLA and NBR separately had the highest toughness and comparable tensile properties. This was attributed to the synergistic effect between the improved PLLA molecular chain entanglement due to the DCP initiated branch reaction of PLLA and improvement of the compatibility between two phases.
[来源：中国聚合物网]