Biobased unsaturated polyesters containing trans-2-butene-1,4 -diol and various dicarboxylic acids: Synthesis, characterization, and thermo-mechanical properties

Abstract

Trans-2-butene-1,4-diol (tB), a renewable unsaturated monomer prepared from erythritol, is a promising building block for future biobased unsaturated polyesters. Herein, a series of biobased unsaturated polyesters based on tB and eight linear α, ω-diacids was explored by melt-polycondensation. Under the optimized reaction conditions, the alkene bonds of tB were intact in the polyester backbones with no isomerization or saturation side reactions taking place during the polymer synthesis even without a radical quencher adding. Surprisingly, the synthetic unsaturated polyesters reached high weight average molecular weight (Mw) up to 93.0 kDa. These results indicated that tB was an ideal unsaturated monomer used for the synthesis of biobased unsaturated polyesters with well-defined structure. Moreover, the structure–property relationships of the unsaturated polyesters were discussed via studying the effect of chain length on crystalline and thermo-mechanical properties. The result of tensile test manifested that tB performed better than 1, 4-butanediol in improving the tensile stress of polyesters. Among the synthetic polyesters, poly(trans-butene suberate)(PtBSu), poly(trans-butene sebacate) (PtBSe), and poly(trans-butene dodecanedioate) (PtBDo) gave Tm of 61.2−78.5 °C, satisfactory crystalline property, and exhibited comparable or even better tensile properties compared with most industrial aliphatic polyesters. Overall, tB was a promising candidate for replacing petroleum-based monomers for the preparation of unsaturated polyesters with superior thermomechanical properties.