Study on tensile properties, microstructure and crystallization behavior of polylactide blends

The tensile properties, micro-structure and crystallization behavior of polylactide binary composites with butylene glycol - adipic acid - ternary terephthalate polyester (PBAT) or polybutylene succinate (PBS) and their ternary composites with further addition of rigid filler LAK (sulfate ingredient) were investigated in this work. The mechanical study indicated that the addition of PBAT or PBS resulted in great improvement of the elongation at break and enhanced the poor toughness of PLA. The addition of LAK particles into 10wt% PLA-PBS system also resulted in the improvement of its elongation at break. The morphology study of PLA tensile fracture surface by SEM indicated the dominated deformation mechanism of toughened PLA blends was attributed to the cavitation formation from the interface between PLA and the second polymer or the rigid particles. Both the addition of PBAT and PBS promoted the crystallization behavior of PLA, and the addition of PBS also resulted in the different type of PLA crystalline. LAK particles acted as nucleating agents in the PLA ternary composites and further decreased the half-crystallization time. Based on the parameters calculated by Avrami equation, the addition of LAK particles into both PLA-PBAT and PLA-PBS system have the similar crystal nucleating and growth process.