Synthesis and Characterization of Poly(butylene terephthalate-co-glycolic acid) Biodegradable Copolyesters

The emergence of biodegradable materials has greatly solved the problem of environmental pollution caused by plastics, but there are still challenges in how to balance the thermal properties, mechanical properties and degradation properties of materials. In this work, a series of poly(butylene terephthalate-co-glycolic acid) (PBTGA) copolyesters with high molecular weights and different glycolic acid content were synthesized via bulk melt polycondensation. TGA demonstrated that the thermal decomposition temperature of all copolyesters were above 360 degrees C, which indicated the copolyesters had excellent thermal stability. DSC and XRD showed that the crystallization of the copolyester was deteriorated with the increase of glycolic acid content, corresponding to melting temperature decreased. The copolyesters had tensile strength of 18.7-46.2 MPa, tensile modulus of 20-1061 MPa and elongation at break between 196-487%. Degradation experiments showed that the weight loss of PBTGA copolyesters in 12 weeks was more than 20%. Through the copolymerization of GA and BT units, GA not only endowed the copolyesters with the ability of rapid degradation, but also kept the copolyesters excellent performance. Therefore, the PBTGAs we synthesized gave us a potential possibility to solve the problem of the plastic pollution.