Synergistic Effect of Epoxy Soybean Oil and Self‐Assembly Nucleator on Enhancing Poly(Lactic Acid) Crystallization

ABSTRACT Poly(lactic acid) (PLA) is a promising biobased biodegradable plastic but suffers from the drawback of a slow crystallization rate. Herein, a biobased plasticizer epoxy soybean oil (ESO) and a self‐assembly nucleator octamethylenedicarboxylic dibenzoylhydrazide (OMBH) were combined with the objective to raise the crystallinity of PLA under practical injection molding. The crystallization behavior was investigated under either isothermal or nonisothermal conditions. In addition, the samples were injection molded and the influence of mold temperature on the crystallinity was evaluated. It is found that ESO and OMBH have a synergetic effect of accelerating PLA crystallization, especially at a high cooling rate. This is further supported by the isothermal crystallization results at a wide crystallization temperature range. The crystallizability of the optimized recipe was enough to receive crystalline articles during the cycle time with the use of hot molds. Dynamic mechanical analysis shows that the combination of ESO and OMBH further improves the temperature resistance of PLA. This work demonstrates that combining ESO with OMBH can considerably improve the crystallization performance of PLA, providing insights for designing temperature‐resistant biobased PLA materials.