Poly (ethylene 2,5-furandicarboxylate) ionomers with enhanced liquid water sorption and oxidative degradation

Aliphatic-sulfonated polyesters based on 2,5 FDCA, such as poly(ethylene 2,5-furandicarboxylate)-co-(ethylene sodiosulfonate succinate) or 2,5-PEF-co-PESs were prepared by a melt step-growth polymerization of 2,5-FDCA and Na-DMSS with ethylene glycol. These copolyesters were characterized by 1H-NMR, DSC and TGA. The degree of randomness determined by 1H-NMR is less than one, thus indicating that these copolyesters have a character to block. All copolyesters were amorphous, having glass transition temperatures decreasing with the content of ionic units. The thermal stability of 2,5-PEF-co-PESs was slightly reduced by the incorporation of these units. The liquid water sorption mechanism was also discussed as a function of the composition of the copolymer and the predominant role of the content of sulfonated groups on liquid water uptake was highlighted. Finally, oxidative degradation has again supported the role of sulfonated units, whereas hydrolytic degradation was not influenced by the concentration of sulfonated groups. By leveraging on their characteristics, 2,5-PEF-co-PESs copolyesters may be can serve as attractive and innovative bio-polymers for practical applications such as textile and membrane…