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Indexed by:期刊论文

Date of Publication:2018-08-01

Journal:EUROPEAN POLYMER JOURNAL

Included Journals:SCIE

Volume:105

Page Number:274-285

ISSN No.:0014-3057

Key Words:Isodimorphism; Even-odd copolyesters; Chain length effect

Abstract:Two series of biobased even-odd aliphatic copolyesters, poly(butylene glutarate-co-butylene azelate) (PBGA) and poly(octylene glutarate-co-octylene azelate) (POGA), were prepared from even diol of 1,4-butanediol or 1,8-octanediol with odd diacids of glutaric acid and azelaic acid, respectively. These even-odd copolyesters can cocrystallize within the entire composition range despite being random, displaying a pseudo-eutectic point when their melting points are plotted as a function of composition. DSC and WAXD studies confirmed the isodimorphic behavior for PBGA and POGA. Then, the competition and miscibility in isodimorphism between PBGA and POGA were comparatively investigated. It demonstrated that the chain length of comonomeric diols can exert a considerable influence on the isodimorphic behavior of copolyesters. The comonomeric diol with longer chain shows greater ability in bridging the gap of competition between comonomer units. This insight contributes to predicting the composition of crystal transition point for isodimorphic copolyesters based on the molecular structure. For miscibility, the mutual insertion of comonomer units in the copolyester containing longer co-monomeric diol is easier than in the copolyester with shorter comonomeric diol. Furthermore, a close dependence between the mechanical properties with competition and miscibility in such even-odd copolyesters was observed and discussed. The composition dependence of yield stress presents a similar pseudo-eutectic behavior that matches those exhibited by T-m versus composition, and that of the elongation at break shows an opposite tendency. In conclusion, our work here not only clarifies the effect of chain length of comonomeric diols on competition and miscibility of isodimorphism in the even-odd copolyesters, but also provides guidance in the selection of comonomeric diol for preparation of aliphatic copolyesters with desirable performances.