Thermoplastic shape memory composites with enhanced recovery stress and recovery ratio based on double roles of PVAc-g-GO

The fabrication of thermoplastic shape memory PLLA-based composites based on simultaneous shape fixed phase role and reinforcement phase role of nanofillers, corresponding to better performance and higher productivity, remains as a great challenge. In this work, polyvinyl acetate grafted GO (PVAc-g-GO) has been employed to prepare shape memory PLLA/PVAc-g-GO composite based on the good miscibility between PLLA and PVAc. The physical entanglement between them produces thermoplastic shape memory composites. Furthermore, the modified GO plays double roles in shape memory performance. On one hand, it can depress the crystallization of PLLA and act as the new shape fixed phase to prevent the irreversible sliding of polymer chains during deformation, accounting for the enhanced shape recovery ratio; on the other hand, storage modulus of the composite at high temperature has been improved with the aid of GO and its excellent dispersion in the PLLA matrix, resulting in higher recovery stress. Our result opens a new avenue for mass production of thermoplastic shape memory PLLA-based composites with enhanced mechanical and shape recovery properties.