Effects of shearing and comonomer content on the crystallization behavior of poly(butylene succinate-co- butylene 2-ethyl-2-methyl succinate)

Abstract

Poly(butylene succinate‐co‐butylene 2‐ethyl‐2‐methyl succinate) (PBSEMS) random copolymers were prepared with different comonomer compositions. The effects of shearing and comonomer content on the crystallization behavior of these copolymers were investigated at 80 °C. The thermal and morphological properties of the resulting samples were also discussed. The copolymers showed a longer induction time and a slower crystallization rate with increasing comonomer content. The promoting effect of shear on the overall crystallization behavior was more notable for those copolymers containing more 2‐ethyl‐2‐methyl succinic acid (EMSA) units. The melting temperature of ‘as‐prepared’ poly(butylene succinate) (PBS) was ca. 115 °C, while that of the copolymers varied from 112 to 102 °C. Higher comonomer contents in the copolymers gave rise to lower melting temperatures and broader melting peaks. In addition, the isothermally crystallized samples showed multiple melting endothermic behavior, the extent of which depended on the comonomer content. The copolymers showed different wide‐angle X‐ray diffraction (WAXD) patterns from that of neat PBS, depending on the comonomer content and shear applied during crystallization. With increasing comonomer content, the copolymers crystallized without shearing, showing the shifting of a diffraction peak to a higher angle, while those crystallized under shear did not show any peak shift. Copyright © 2004 Society of Chemical Industry