Study on tensile stress fluctuation of poly(butylene succinate) (PBS) and its bicrystalline block copolyesters (PBSEG)

Abstract Based on the stress fluctuation during the tensile process of poly(butylene succinate) (PBS), the tensile behavior of biodegradable bicrystalline block copolyesters (PBSEG) synthesized using polycondensation of poly(ethylene glycol) (PEG) and poly(butylene succinate) (PBS) was further studied. The effects of tensile rate and temperature test conditions on the stress–strain behavior of bicrystalline block copolymer PBSEG were investigated by conducting tensile tests. The experimental results showed that when the mass content of polyethylene glycol in PBSEG was 60%, the material did not show obvious periodic stress fluctuation during the “cold drawing” stage of the stress–strain curve, but showed different and more complicated periodic curve changes. The stress fluctuation of PBSEG copolyester had the characteristics of small amplitude and short period. The elongation at break increased obviously, and the maximum elongation at break was more than 2000%. The analysis of morphology and structure showed that the surface morphology of PBSEG dumbbell bars did not show obvious alternating changes in structure, characterized by light and dark. Craze was the main cause of ductile fracture for PBS and PBSEG copolyesters. The tensile fracture of the two materials occurred in the stress fluctuation region. Highlights Small‐amplitude and short‐period stress fluctuation for PBSEG copolyester. There was no alternating light and dark on the surface of the PBSEG stretched spline. Craze was the main cause of ductile fracture for PBS and PBSEG copolyesters. Tensile fracture of the materials occurred in the stress fluctuation region.