Sulfonated biodegradable PBAT copolyesters with improved gas barrier properties and excellent water dispersibility: From synthesis to structure-property

Poly(butylene adipate-co-terephthalate) (PEAT) is one of the major commercialized biodegradable polymers. But modification of PEAT is still necessary to satisfy requirements of various applications. In this study, PEAT-based sulfonated copolyesters (PBATsI) with various compositions (7-12 mol% sulfonated unit) were synthesized by copolycondenation using dimethyl isophthalate-5-sulfonate sodium (SIPM) as a functional comonomer. The copolyesters were characterized with H-1 NMR, viscometer, DSC and XRD, and evaluated with TGA, tensile, gas barrier, contact angle and water dispersion testing. For the first time, it was found that the sulfonated copolyesters manifest improved color, clearly higher O-2 and CO2 barrier properties, better hydrophilicity and excellent water dispersibility when compared with PEAT. The copolyesters containing 9-12 mol% BsI unit can be facilely dispersed in water to obtain stable dispersions with unimodal particle size distribution in < 100 nm range. These advantages may help them to find uses in tuning biodegradation rate of PEAT and further physical modification of PEAT. (C) 2020 Elsevier Ltd. All rights reserved.