Effect of PLA/TiO2/Lg filler competition and synergy on crystallization behavior, mechanics and functionality of composite foaming materials

In this study, a method for preparing high expansion ratio, high cell density PLA foams based on a combination of titanium dioxide(TiO 2 ) and lignin(Lg) is demonstrated. TiO 2 can act as a rigid core to generate heterogeneous nucleated crystals and increase the strength of the PLA matrix, Lg can be used as a polymer plasticizer with good dispersibility to improve the mobility of PLA molecular chains and reduce the entanglement between molecular chains. By studying the competition and synergy of two nucleating agents in the nucleation process, Lg exhibits a significant nucleation-promoting effect compared to TiO 2 in the case of a single nucleating agent. While adding 5 wt% TiO 2 /Lg, the high content of TiO 2 /Lg provided the best synergistic effect to accelerate the overall crystallization. In addition, the 1 wt% PLA/Lg composite foams prepared in this work also exhibited excellent foaming properties.