Synthesis and properties of 1, 4-cyclohexanediol modified PBAT copolyesters

Poly (butylene adipate-co-butylene terephthalate) (PBAT) is a biodegradable polyester that has garnered significant attention in recent years. However, its relatively low tensile strength and elastic modulus have limited its practical applications. In this study, a novel poly(terephthalate-cyclohexanediol co-adipate/butyl terephthalate co-adipate) (PBSAT) was synthesized via melt condensation. The structure and composition of the synthesized copolyester were characterized using FT-IR and ¹H-NMR spectroscopy, while XRD, DSC, TG, and mechanical tests were conducted to evaluate its properties. The molecular weight, thermal properties, mechanical properties, processability, and hydrophilicity of the copolyesters were measured using an Ubbelohde viscometer and water contact angle measurement. The results indicated that 1,4-cyclohexanediol (14 CHDO) did not significantly alter the crystal structure of PBAT. The properties of the copolyesters were found to be dependent on the amount of 14 CHDO added. When the 14 CHDO content was 7.5%, the copolyesters exhibited optimal mechanical properties, with a tensile strength of 24.85 MPa and an elastic modulus of 216 MPa, representing increases of 29.7% and 28.5%, respectively, compared to PBAT. PBSAT copolyester demonstrated superior heat resistance, enhanced hydrophilicity, and improved processability, along with increased crystallinity. This new PBSAT copolyester offered better overall performance and held promise for replacing commercial PBAT, thereby expanding its application scope.