writer：?Chengqian Pan, Jing Lu, Binshuang Wu, Linbo Wu*, Bo-Geng Li.
keywords：Biodegradable polymers; Flexible copolyesters; Aliphatic-aromatic copolyesters; Crystallization; Glass transition.
source：期刊
specific source：J Polym Environ 2016 doi:10.1007/s10924-016-0881-5
Issue time：2016年

Biodegradable amorphous flexible (co)polyesters with low glass transition temperature (Tg) are very desirable in some specific biodegradable applications like impact modification of brittle polymers and synthesis of elastomers. However, most biodegradable flexible polyesters and binary copolyesters made from diacid(s) and diol(s) are crystalline polymers. In order to investigate the structure dependences of crystallizability and Tg of such copolyesters, seventeen random copolyesters were designed and  synthesized in this study, and characterized with 1HNMR, GPC, DSC,  TGA and tensile testing. Introducing aromatic (especially asymmetric or rigid)  diacid or short-chain branched diol is favorable to depress copolyester crystallization, and leads to higher Tg at the same time. From easily crystallized to fully amorphous copolyesters with low Tg have been successfully synthesized by adopting different combination of the structural units. In addition, the existence of aromatic structural unit in copolyesters is helpful to improve their tensile properties.