Synthesis and characterization of novel poly(butylene succinate)-b-poly (diethylene glycol terephthalate) multiblock copolyesters with high melting point and significantly improved mechanical property

Biodegradable poly(butylene succinate) (PBS) has extensively been studied; however, its relatively high crystallinity and poor toughness restricts its wide application. In this research, novel poly(butylene succinate)-b-poly (diethylene glycol terephthalate) (PBS-b-PDEGT) multiblock copolyesters with different mass ratios of amorphous hard PDEGT and crystallizable soft PBS segments were successfully synthesized and confirmed by hydrogen nuclear magnetic resonance. Both PBS homopolymer and PBS-b-PDEGT multiblock copolyesters displayed high thermal stability. In PBS-b-PDEGT multiblock copolyesters, PBS and PDEGT segments were partially miscible in the amorphous region. Compared with PBS homopolymer, the introduction of PDEGT segment slightly reduced the melting point of PBS-b-PDEGT multiblock copolyesters. The crystallization mechanism and crystal structure of PBS segment did not change. With the increase of the PDEGT segment content, the Young's modulus of PBS-b-PDEGT multiblock copolyesters gradually decreased, while the elongation at break remarkably increased. In brief, the synthesis of PBS-b-PDEGT multiblock copolyesters provides an efficient modification method of preparing novel PBS copolymers with still high melting point (about 110 degrees C) and significantly improved elongation at break (about 650% and above), which should be greatly important and helpful from a practical application viewpoint.

Automated summary

Novel PBS-b-PDEGT multiblock copolyesters with different mass ratios of amorphous hard PDEGT and crystallizable soft PBS segments were successfully synthesized in this study. These copolyesters showed high thermal stability and significantly improved elongation at break compared to PBS homopolymer. The introduction of PDEGT segment slightly reduced the melting point while increasing the elongation at break.