(446e) Synergistic Enhancement of Barrier, Aging Resistance, and Hydrolysis for Biodegradable Copolyesters Based on Poly(butylene adipate terephthalate) and Polyglycolic Acid

As one of the most promising biodegradable plastics, PBAT has attracted immense attention in the fields of packaging and mulch films. However, limitations of degradation performance in aqueous environment and mechanical properties hinder its further development. In this work, we focused on chain structure design, introduced glycolic acid units into the PBAT backbone, and synthesized a series of PBAT-co-PGA copolyesters with different compositions and sequence structures by melt copolycondensation. The number-average sequence length of the copolymer units can be varied while keeping its molar content unchanged by adjusting the molar ratio of copolymer monomer in PBAT-co-PGA. PBAT-co-PGA exhibited higher Young's modulus (88 MPa) and tensile strength (35 MPa) due to the better crystallization ability compared to PBAT with the same content of terephthalic acid. We found that incorporation of more terephthalic acid and glycolic acid resulted in higher glass-transition temperature and a rigid chain structure, which is beneficial to improve the water vapor barrier properties of copolyesters. Additionally, PBAT-co-PGA copolyesters showed enhanced hydrolytic degradablity in lipase and alkaline solutions without sacrificing the aging resistance. The synthetic strategy proposed here endow the PBAT-co-PGA copolyesters with a wider chain structure regulation window than PBAT, which makes it have excellent mechanical, H₂O barrier, and ageing-resistant properties, also accelerates the enzymatic and non-enzymatic hydrolysis of copolyester.