Synthesis of bio-based copolyester and its reinforcement with zinc diacrylate for shape memory application

We synthesized fully bio-based poly(propylene sebacate) using 1,3-propanediol, sebacic acid, and itaconic acid as raw materials. Another bio-based diacid, succinic acid, was introduced to tailor the flexibility of the copolyester. Accordingly, we obtained a series of crosslinkable copolyesters, covering from rigid plastics to soft elastomers. The rigid copolyesters could be used as shape memory polymers (SMPs). As the elastomeric copolyesters (noncrystalline ones and crystalline ones above T_m) are mechanically weak, zinc diacrylate (ZDA) was used as reinforcement to enhance the tensile strength and storage modulus in rubbery state. ZDA exhibited high reinforcing efficiency for the copolyesters. For instance, tensile strength and storage modulus above T_m of poly(propylene sebacate) (PPSS0) reinforced by ZDA (40 phr) increased by 368% and 745%, respectively. ZDA showed good compatibility with the copolyesters and polymerized ZDA particles dispersed uniformly in the matrices. Additionally, PPSS0/ZDA composites exhibited high shape fixity and shape recovery, making them suitable for fabricating biobased SMPs.