2,5‐Furandicarboxylic Acid‐Modified PBAT Copolyesters: Enhanced Mechanical Properties, Gas Barrier Performance, and UV Aging Resistance

ABSTRACT Driven by the depletion of petroleum resources and demand for sustainable materials, developing high‐performance bio‐based polyesters with tunable degradation behavior has attracted increasing attention. Herein, a partially bio‐based copolyester (PBAFT) was synthesized via a one‐step copolymerization strategy by partially replacing terephthalic acid (TPA) with bio‐based 2,5‐furandicarboxylic acid (FDCA) in poly (butylene adipate‐co‐terephthalate) (PBAT). The rigid furan ring and polar oxygen atoms of FDCA endowed PBAFT with enhanced storage modulus, mechanical performance, barrier properties, and degradation behavior. PBAFT containing 10 mol% FDCA substitution exhibited a tensile strength of 32.5 MPa (increased by 89.6%) and elongation at break of 1067.6%, while maintaining high mechanical strength after UV aging. Meanwhile, FDCA incorporation significantly reduced water vapor permeability (2.5 g mm/[m 2 24 h]) and oxygen permeability (81.6 cc mm/[m 2 24 h]). Furthermore, PBAFT copolyesters demonstrated controllable alkaline hydrolytic degradation with pronounced surface erosion, crack propagation, and mass loss under accelerated alkaline conditions. Therefore, FDCA‐based molecular regulation provides an effective strategy for developing high‐performance bio‐based copolyesters.