Bisfuranic copolyesters bearing nitrated units: synthesis, thermal properties and degradation essays

In this study we report a series of partially biobased new (hetero)aromatic copolyesters, namely poly(ethylene-bis(ethyl 2-furoate)-co-ethylene 5-nitroisophthalate)s synthesised via the two-step melt polycondensation process, by combining commercially available dimethyl 5-nitroisophthalate and a biobased bisfuranic diester derivative (DEF), and ethylene glycol. Their expected molecular structure was confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies. All copolyesters display excellent thermal stability and a glass transition temperature ( T g ) up to 72 °C, decreasing slightly with the increasing amount of the nitro derivative content. Furthermore, these copolyesters revealed to be essentially amorphous materials. The hydrolytic degradation was investigated for all copolyesters at 37 °C and the oxidative degradation only for the copolyester containing theoretically equimolar amount c.a. PEBF 50 NI 50 .The oxidative degradation shows well weight loss up to 56wt.% after 15 days of incubation, confirmed by 1 H NMR analysis.