High molecular weight copolyesters based on poly(butylene terephthalate) (PBT) as rigid aromatic segments and poly(L-lactic acid) (PLLA) as degradable aliphatic segments were synthesized via polycondensation of terephthalic acid (TPA), 1,4-butanediol (BDO), 1,4-cyclohexanedimethanol (CHDM) and poly(L-lactic acid) oligomer (OLLA).Through tailoring the molar ratio of diols (BDO and CHDM), the effect of CHDM unit on the synthesis, mechanical properties and thermal stabilities as well as the degradation behaviors of the copolyesters was investigated. With the increase of CHDM content, the initial decomposition temperature (Tonset) increased from 282.5 ºC to 322.2 ºC and the tensile strength improved by nearly four times from 5.4 MPa to 19 MPa. When the CHDM was 5 %, the weight-average molecular weight of the copolyester was up to 89400 g/mol with a polydispersity of 1.96. In phosphate buffer solution the degradation rate of the copolyesters displayed a strong dependency on the temperature and CHDM composition.
