Synthesis of novel thermoplastic polyester elastomers with biobased amorphous polyester as the soft segment

The development of sustainable polymers from biobased blocks is urgently desirable. In this work, a class of novel biobased thermoplastic polyester elastomers, namely poly(butylene terephthalate)-poly(1,4-butylene/2,3-butylene succinate) (PBT-PBBS) copolyesters, were designed and synthesized via melt oligomer polycondensation of common PBT oligomer and biobased PBBS oligomer. The obtained PBT-PBBS copolyesters exhibited desired block structure and contained a hard phase of crystallized PBT and a soft phase of amorphous PBBS. Their mechanical properties could be tailored by tuning the polycondensation time or the molar ratio of PBT to PBBS. Specifically, the tensile strength and the elongation at break of these copolyesters could be flexibly adjusted in the range of 6–13 MPa and 240–650%, respectively. Therefore, they are expected to be widely used in the fields of elastomers, hot-melt adhesives, and toughening modifiers.