Shape Memory Temperature-Tunable Poly(butylene adipate-<i>co</i>-terephthalate)/Polylactic Acid Foams Prepared by Supercritical CO<sub>2</sub> Foaming
Zheng Gong, Yichong Chen, Jie Yuan, Ling Zhao, Dongdong Hu
Abstract
Lightweight, shape memory temperature-tunable, biodegradable, and reusable poly(butylene adipate- co -terephthalate) (PBAT)/polylactic acid (PLA) foams with acetyl tributyl citrate (ATBC) were prepared by a simple, green, and efficient supercritical CO 2 foaming technique. ATBC reduces the glass transition temperature ( T g ) of PLA in PBAT/PLA composites and, thus, decreases the switching temperature of the shape memory in PBAT/PLA foams. ATBC widens the shape memory applicable temperature range, and the applicable temperature shifts toward lower temperatures. The minimum shape memory applicable temperature is 50 °C. ATBC can also accelerate the shape recovery process. In addition, increased shape memory temperature favors the shape fixing ratio ( R f ) and recovery ratio ( R r ) and can shorten the shape recovery time. PBAT/PLA foam exhibits a low density of 0.16 g/cm 3, an R f of 93.6%, and an R r of 95.2%. PBAT/PLA foam also has reusability; both R f and R r remain above 85% after 10 cycles.