Enhanced Impact Properties of Polylactide by Poly(lactide-￡-butadiene-6-lactide) Triblock Copolymer

摘要

Polylactide (PLA) was copolymerized with polybutadiene (PBD) to improve its impact properties. Triblock copolymers of poly(lactide-b-butadiene-b-lactide) (PLBDL) were obtained by the ring opening polymerization of lactide using tin 2-ethylhexanoate (Sn(Oct)2) and hydroxyl terminated polybutadiene (HTPBD) as a catalyst and macroinitiator, respectively. PLA and PLBDL were blended at 5, 10, and 15 wt% PLBDL. After blending, the samples exhibited a shift in the T_g of PLA, which means that PLBDL and PLA are compatible. The tensile strength and Young's modulus decreased with increasing PLBDL. On the other hand, the PLA/PLBDL blend containing 10 wt% PLBDL showed a 4 fold increase in impact strength. In addition, the elongation at break of the blend containing 10 wt% PLBDL was 467%, showing a 27 fold increase compared to neat PLA. This suggests that the PBD chains on the PLBDL backbone have a significant effect on the impact properties of PLA.