Preparation of antishrinkage and high strength poly(butylene adipate-co-terephthalate) microcellular foam via in situ fibrillation of polylactide

High-expansion-ratio microcellular poly (butylene adipate-co-terephthalate) (PBAT) foams exhibit severe shrinkage, which hinders their industrial applications. This study provides a facile method to prepare low-shrinkage, high-compressive-strength and high-resilience PBAT foam. CEPBAT/PLA blends (CE = chain extender, PLA = polylactide) were prepared via in situ fibrillation to obtain CEPBAT/PLA-S (CEPBAT/PLA containing PLA spherical phase) foam containing PLA spheres and CEPBAT/PLA-F (CEPBAT/PLA containing PLA fiber phase) foam with PLA nanofibers. The effects of the PLA nanofibers and spheres on the antishrinkage and compression strength of the PBAT foams were studied. The PLA nanofibers exhibited a higher specific surface area than the PLA spheres and a supporting network structure for the PBAT foam, thereby improving its melt strength. As a result, the antishrinkage performance and compression strength of CEPBAT/PLA-F improved by 100 % and 180 %, respectively, compared with the neat PBAT foam after aging for 144 h. However, the permanent deformation of CEPBAT/PLA-F increased only slightly after ten compression cycles. CEPBAT/PLA-F showed better antishrinkage performance, compression strength, and resilience than CEPBAT/PLA-S owing to the interface effect of the PLA nanofibers, whose nanolinear network structure provides enhancement and a larger deformation range under pressure to reduce plastic deformation.