Crystalline layered morphology in the phase-separated blend of poly(butylene succinate) and poly(ethylene succinate)

Spherulitic morphology of the phase-separated blend of two crystalline polyesters, poly(butylene succinate) (PBS) and poly(ethylene succinate) (PES), was investigated using polarized optical and atomic force microscopes. The thin crystalline layers of PBS were exhibited on the PES-rich phases in the blend melt-crystallized at the crystallization temperature of PBS then at that of PES successively. The PBS–PES copolyesters that form through transesterification between PBS and PES in the melt, preferentially localize at the interface and can stabilize the layered structure.