Effect of Crystallization on Shape Memory Effect of Poly(lactic Acid)

The opportunity for the preparation of high-performance shape memory materials was brought about by the excellent mechanical properties of poly(lactic acid) (PLA). As the effect of crystallization on shape memory was still unclear, this brings constraints to the high-performance design of PLA. The PLA plates with different aggregation structure were prepared by three kinds of molding methods in this paper. The PLA plates were pre-stretched with a series of different strains above glass transition temperature (i.e., 70 degrees C). The recovery stress and ratio of the material were measured above stretching temperature (i.e., 80 degrees C). Prolonging of annealing time resulted in more perfect crystal structure and higher crystallinity. The crystal region acted as network nodes in shape memory PLA, and crystal region structure determined the shape memory performance. Based on the experimental results, the structural evolution of network nodes in shape memory PLA was established.

Automated summary

This study investigates the influence of crystallization on the shape memory properties of PLA by preparing PLA plates with different aggregation structures. The results show that the crystal region structure determines the shape memory performance. This research contributes to the design and fabrication of high-performance shape memory materials.