Synthesis, properties, and hydrolysis of bio-based poly(butylene succinate-co-diethylene glycol succinate) copolyesters

Microplastic has become the focus of environmental pollution recently, especially in seawater. Due to its high crystallinity and hydrophobicity, the degradation rate of poly(butylene succinate) (PBS) is slow. In this paper, a series of poly(butylene succinate-co-diethylene glycol succinate) (PBSD) copolymers were synthesized by melt-polycondensation in order to improve the nonenzymatic hydrolysis of PBS. The contact angle and water uptake content of copolymer were increased obviously when the regular crystalline structure of chain segment was disturbed by diethylene glycol. Rheological tests revealed the microphase separation structure occurred at 130 degrees C. The tensile strength of PBSD40 copolymer was 15 MPa and the elongation at break was more than 700%, and the decomposition temperature was above 370 degrees C. The weight loss of PBSD60 copolymer in acid condition was 98.6% after 49 days at 50 degrees C. However, in neutral condition and simulated seawater, the weight loss was less than 10%. Acid and alkaline catalyzed the hydrolysis of ester bonds. Some holes and cracks appeared at the surface of the samples after degradation from SEM analysis. Thus, PBSD copolymers have the potential to serve as promising water degradable materials.