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

Abstract

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 °C) and significantly improved elongation at break (about 650% and above), which should be greatly important and helpful from a practical application viewpoint.