Preparation and Properties of Polylactic Acid-Based Shape Memory Composites

In this paper, poly(lactic acid) (PLA)/thermoplastic polyurethane (TPU) binary blend composites were prepared by a melt blending method using PLA as the substrate and TPU as the toughening component, to which carbon nanotubes (CNT) were added, and PLA/TPU/CNT shape memory composites with light-responsive and heat-responsive shape memory properties were prepared. The mechanical properties, micro-morphology, light-responsive, and heat-responsive shape memory properties of the prepared composites were investigated. The results showed that the toughening effect of thermoplastic polyurethane was best when the ratio of PLA to TPU was 8:2, based on which the light-converting particle CNT was added to prepare the light- and heat-responsive PLA/TPU/CNT ternary composites. The better the dispersion of CNT, the better the mechanical properties, stiffness, and shape memory properties of the composite. When the CNT content is 3 wt%, the shape memory performance is the best, and the composite has fast-response optical and thermal shape memory properties and high recovery ability, which can reach 100% under continuous light and heating conditions. Based on the composites, opto-thermal responsive smart packaging boxes and flower-shaped series–parallel integrated switch models were designed, expanding the applications of composites in the fields of smart packaging materials and electronic devices.