Crystallization property, mechanical performance and enzymatic degradation behavior of PBS copolyesters modified by 2‐methyl‐1,3‐propanediol

The poly(butylene succinate) (PBS) copolyesters modified by 2‐methyl‐1,3‐propanediol (MPO), that is poly(butylene succinate‐co‐methyl propylene succinate) (PBMS), were synthesized by direct esterification‐melt polycondensation method. 1H NMR showed the PBMS molecules contain two repeating structural units, the butylene succinate (BS) and the 2‐methyl‐1,3‐propylene succinate (MS). The crystalline properties of PBMS were characterized by DSC, POM, and XRD. The results showed the relative crystallinity of PBMS decreases from 45.12% to 38.2%, the size of spherulites also decreases, and the crystallization ability becomes weaker compared with PBS. The water contact angle test proved the surface hydrophilicity of PBMS is improved. The impact strength of PBMS increases from 3.9 to 24.6 kJ/m2, and its elongation at break increases from 10.5% to 71.2%, and the transition from brittle fracture to ductile fracture is achieved. The study of enzymatic degradation found that the enzymatic degradation rate of PBMS copolyesters increases significantly with the increase of MPO content. Within 25 days of degradation, the weight loss rate of PBS after degradation is 38.18%, while that of PBMS reaches 100%. Finally, it was also observed the enzymatic degradation of PBS and PBMS starts from the amorphous region and abides by the regular pattern from the periphery to the middle and from the surface to the interior. Synthetic pathway of PBMS, enzymatic degradation rate, and surface morphology during degradation of PBS and PBMS.