Fully Bio‐Based 2,5‐Furandicarboxylic Acid Polyester Toward Plastics with Mechanically Robust, Excellent Gas Barrier and Fast Degradation

Aliphatic-aromatic copolyesters offer a promising solution to mitigate plastic pollution, but high content of aliphatic units (>40%) often suffer from diminished comprehensive performances. Poly(butylene oxalate-co-furandicarboxylate) (PBOF) copolyesters were synthesized by precisely controlling the oxalic acid content from 10% to 60%. Compared with commercial PBAT, the barrier properties of PBOFs for H2O and O2 increased by more than 6 and 26 times, respectively. As the reduced water contact angle to from 82.5° to 62.9°, superior hydrophilicity gave PBOF an excellent degradation performance with a 35-day hydrolysis. Interestingly, PBO20F and PBO30F also displayed obvious weight loss during hydrolysis, with Mn less than 1/10 of the original values. Their elastic modulus (>1 GPa) and tensile strength (35 and 54 MPa) exceeded those of HDPE and most biodegradable polymers. PBOF achieve the highest hydrolysis rates among the reported PBF-based copolyesters. The hydrolytic mechanism was further explored based on Fukui function analysis and density functional theory calculation. Noncovalent analysis indicated that the water molecules formed hydrogen bonding interaction with adjacent ester groups and thus improved the reactivity of carbonyl carbon. PBOF copolyesters meet the requirements of high-performance packaging market and can quickly degrade after usage, providing a new choice for green and environmental protection.