Improved Mechanical Properties and Gas Barrier Properties for a Recyclable FDCA-Based Polyesters by Constructing Hydrogen-Bonded Crosslinked Network

Petroleum-based monomers, such as terephthalic acid (TPA), are extensively utilized in the manufacture of disposable packaging materials. In light of the rapid depletion of fossil fuel resources and the escalating environmental challenges, the development of bio-based monomers and polymers have gained significant momentum. Among them, 2,5-furandicarboxylic acid (FDCA) is widely recognized as a sustainable substitute for TPA. However, FDCA-based polyesters often suffer from limitations in toughness. Herein, we report the synthesis of poly(hexamethylene furandicarboxylate-4-hydroxy-N-(2-hydroxyethyl)pentanamide) (PHHFx) through the integration of 4-hydroxy-N-(2-hydroxyethyl)pentanamide (HHPA) into the polymer chain. The incorporation of HHPA facilitates the formation of hydrogen-bonded crosslinked network in PHHFx, effectively enhancing the mechanical performance (i.e., ε b and σ b are 382.9% and 38.2 MPa) and gas barrier properties (i.e., O 2 0.008 barrer, CO 2 0.024 barrer, and H 2 O 1.53×10 -14 g·cm·cm -2 ·Pa -1 ·s -1 ). In addition, PHHFx exhibit efficient chemical recyclability under mild conditions, achieving high monomer recovery yields. This work demonstrates a viable strategy for designing high-performance, chemically recyclable bio-based polyesters, addressing both the pressing energy crisis and environmental pollution challenges.