Biodegradable aliphatic/aromatic copolyesters

poly(butylene terephthalate-co-lactate) (PBTL) were prepared via direct melt polycondensation of terephthalic acid (TPA)

1

4-butanediol (BDO) and poly(L-lactic acid) oligomer (OLLA). The effects of polymerization time and temperature

as well as aliphatic/aromatic moiety ratio on the physical and thermal properties were investigated. The largest molecular weight of the copolyesters was up to 64100 with molecular weight distribution index of 2.09 when the polycondensation was carried out at 230C for 6 h. DSC

XRD

DMA and TGA analysis clearly indicated that the degree of crystallinity

glass-transition temperature

melting point

decomposition temperature

tensile strength

elongation and Youngs modulus were influenced by the ratio between TPA and OLLA in the final copolyesters. Hydrolytic degradation results demonstrated that the incorporation of biodegradable lactate moieties into the aromatic polyester could efficiently improve hydrolytic degradability of the copolymer even though it still had many aromatic units in the main chains.