Bio-Based Polyesters with High Glass-Transition Temperatures and Gas Barrier Properties Derived from Renewable Rigid Tricyclic Diacid or Tetracyclic Anhydride

Novel tricyclic diacid (TCDA) and tetracyclic anhydride (TCAH) were synthesized from renewable furan to generate a series of bio-based polyesters via melt polymerization (MP) of TCDA with seven linear α,ω-diols and ring-opening polymerization (ROP) of TCAH with three different epoxides. NMR and single-crystal X-ray revealed a unique rigid W-shaped skeleton of TCDA and TCAH, which was readily converted in diester units to the stable configuration during polymerization. The multicyclic rigid structure imparts high glass-transition temperature (T_g) comparable to petrochemical polymers with the MP polyesters reaching up to 109 °C and ROP polyesters reaching up to 174 °C. In addition, the rigid tricyclic moiety attributes to superior gas barrier properties of the 2,5-furandicarboxylic acid-based polyester, which are significantly better than that of current bio-based polyester poly­(butylene succinate) and polylactide. The outstanding heat tolerance and gas barrier properties of these multicyclic polyesters appear to be promising as substitutes for common industrial petrochemical-based polyesters.