Novel eco-friendly random copolyesters of poly(butylene succinate) containing ether-linkages

摘要

Poly(butylene succinate/diglycolate) random copolymers (P(BSxBDGy)) of various compositions were synthesized and characterized from the molecular, thermal, structural and mechanical point of view. All the polymers showed a good thermal stability and at room temperature they appeared as semicrys-talline materials. The main effect of copolymerization was a lowering in the crystallinity and a decrease of T_m respect to homopolymers. The dependence of T_m on composition for copolymers with high butylene succinate unit content was well described by Baur's equation. WAXD measurements indicated that two different crystalline phases are present, depending on composition: copolymers with high BS unit content are characterized by PBS crystal phase, whereas those rich in BDG co-units crystallized in PBDG lattice. Amorphous samples showed a monotonic increment of T_g as the content of BDG units is increased and this can be explained on the basis of interchain interactions, due to the high electronegativity of ether-oxygen atoms. A Fox-type equation was found to fit the T_g data of completely amorphous samples, permitting the extrapolation of pure PBS T_g value for the completely amorphous polymer.