Synthesis and characterization of 2,5-furandicarboxylic acid poly(butanediol sebacate-butanediol) terephthalate (PBSeT) segment copolyesters with excellent water vapor barrier and good mechanical properties

In order to improve the performance of biodegradable materials, aliphatic–aromatic copolyesters were synthesized from sebacic acid, terephthalic acid, 1,4-butanediol and 2,5-furandicarboxylic acid via two-step esterification and polycondensation. Copolyesters were characterized by intrinsic viscosity, gel permeation chromatography, X-ray diffraction, Fourier infrared spectroscopy, nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis, lipase biodegradation, tensile and cup method testing. All the copolyesters had a weight-averaged molecular weight over 61,000 g/mol or intrinsic viscosity over 1.1 dL/g when the 2,5-furandicarboxylic acid content was in the range from 2 to 10% of terephthalic acid content. Particularly, the tensile strength, yield strength, elongation at break, molecular weight and water vapor barrier of copolyesters were improved to different extents. Obviously, the addition of 2,5-furandicarboxylic acid did not significantly affect the glass transition temperature and thermal stability of polyesters. When the addition amount of 2,5-furandicarboxylic acid was 10%, the water vapor barrier of copolyester reached the highest, which was increased by 89% compared with PBAT. On the whole, the copolyesters with the addition of 6% of 2,5-furandicarboxylic acid had the best comprehensive performance, which was conducive to promoting the application of biodegradable agricultural mulching and food packaging film. Graphical abstract