Poly(butylene succinate)-poly(ethylene glycol) multiblock copolymer: Synthesis, structure, properties and shape memory performance

Thermally-induced shape memory multiblock poly(ether-ester)s (PBSEGs) comprising crystallisable poly(butylene succinate) (PBS) hard segments and poly(ethylene glycol) (PEG) soft segments, were synthesized by polycondensation from succinic acid, 1,4-butanediol and PEG diol. The copolymers were characterized by 1H-NMR, GPC, DSC and DMA. DSC analysis revealed that all PBSEGs prepared in this work are double-crystalline copolymers which ensure it to form separated crystalline domain determined the permanent shape and temporary shape respectively. The Tm of PEG segment (Tm,PEG) of the PBSEGs ranging from 27.54 to 51.04 °C, acting as the transition temperature (Ttrans), was controllable by varying the chain length of soft segment. The DMA test indicated that a large difference in modulus below and above the Ttrans of PBSEGs endows it with sufficient deformability at high temperature and high capacity for keeping deformation at low temperature. The mechanical properties of the copolymer films were assessed by tensile strength measurement. It showed that the copolymers were ductile which enabled remarkable reversible deformation. The shape memory properties of PBSEGs were evaluated by bending test, as expected, most copolymers possessed excellent shape memory effect. The contact angle tests demonstrated that the copolymers were more hydrophilic with the introduction of PEG segment, suggesting this biodegradable PBSEG multiblock copolymer with excellent shape-memory properties has great potential in application for biomaterials.