Dual-Phase Poly(lactic acid)/Poly(hydroxybutyrate)-Rubber Copolymer as High-Performance Shape Memory Materials

In this work, a series of shape memory biopolymers based on a dual-phase poly(lactic acid) and poly(hydroxybutyrate)-rubber copolymer (PLA/PHB-rubber) were developed, exhibiting significant flexibility and well-balanced shape memory (SM) performance. The incorporation of PHB-rubber emerged as numerous well-dispersed microsized domains that partially penetrated the PLA domain, as revealed by the reduction of glass-transition temperature in the differential scanning calorimetry (DSC). The overall increase in crystallinity with the increasing PHB-rubber contributed to a high shape fixity of ∼99% and recovery of ∼95%, where the crystalline domains of PLA and PHB regions constituted as effective anchors for shape fixing, while the rubbery segment that constituted the switching phase provides considerable chain crusade. Concurrently, the PHB-rubber phase promotes considerable interfacial interaction with the PLA phase, as revealed by the field-emission scanning electron microscopy (FESEM) studies. Remarkably, the macroscopic triple-coiled shape recovery was accomplished in just 3 s. The developed dual-phase binary polymer shows great potential as a shape memory polymer for biomedical applications.