Synthesis of Poly(butylene adipate terephthalate)-co-poly(glycolic acid) with Enhanced Degradability in Water

Abstract

As one of the most promising biodegradable polymers, poly(butylene adipate-co-terephthalate) (PBAT) has attracted immense attention in packaging and mulching film applications. However, their slow degradation performance in aqueous environments remains a great challenge. In this work, we focused on tailoring the chain structure of PBAT by introducing poly(glycolic acid) (PGA) into the copolyester backbone. The PBAT-co-PGA copolyesters with molar percentages of butylene terephthalate of 36.2−50.3 mol % and GA of 8.0−20.2 mol % and numberaverage sequence lengths of poly(butylene terephthalate) of 1.55−1.97 and PGA of 1.06−1.11 were synthesized using a melt copolycondensation. The number-average sequence length of the PBAT-co-PGAs can be tailored while maintaining the same monomer composition. The PBAT-co-PGAs exhibit higher Young's modulus (88 MPa) and tensile strength (35 MPa) owing to their better crystallization ability compared with PBAT at the same terephthalic acid fraction. The incorporation of more terephthalic acid and glycolic acid results in an increase of glass transition temperature and the formation of a more rigid chain structure, which is beneficial to improving the water vapor barrier properties of the copolyesters. Importantly, the PBAT-co-PGA copolyesters show enhanced degradation properties in water environments without sacrificing their aging resistance. The synthetic strategy proposed here endows the PBAT-co-PGA copolyesters with a broad chain structure tailoring window, which renders them to exhibit excellent mechanical properties, water barrier, aging resistance, and, most importantly, accelerated hydrolysis performances in aqueous environments.

Chemical Recycling of Poly(butylene terephthalate) into Poly(ethylene brassylate-co-butylene terephthalate) with Tunable Thermal, Mechanical and Biodegradable Properties

“…To further verify the crystallization of aliphatic and aromatic polyester segments, wide-angle X-ray scattering (WAXS) experiments of all PEBBTs copolyesters were conducted, with the curves presented in Figure . PEBBT- n ( n = 1/4, 1/3, 1/2, and 1/1) exhibits a PBT-like triclinic crystal structure, with obvious diffraction peaks located at 2θ values of 16.5, 17.6, 20.6, 23.3, and 24.9°, which are assigned to the (011), (010), (101), (100), and (111) crystal planes, respectively. With the increasing EB content, the diffraction peaks of PBT gradually decreases.…”

Synthesis of Spinnable Poly(ethylene terephthalate-co-glycolate) with Enhanced Degradability

“…It has been found that catalysts have a significant influence on copolyester chain structures. − Four types of catalysts, stannous octanoate, tetrabutyl titanate, ethylene glycol antimony, and antimony trioxide, were used to synthesize the PET-GAs with a GA/PTA feed molar ratio of 20/80 (Table and Figure S4). The polycondensation times for four catalysts at 0.02 mol % based on the total acid group ( C cat ) were 91 min (Run 1), 52 min (Run 3), 133 min (Run 5), and 146 min (Run 6), respectively, to achieve the [η] of 0.65 dL/g for the resulting copolyesters.…”

Biodegradable Copolyesters Derived from 2,5-Thiophenedicarboxylic Acid for High Gas Barrier Packaging Applications: Synthesis, Crystallization Properties, and Biodegradation Mechanisms

“…Biodegradation results from the decomposition of polyester backbones by hydrolysis of ester bonds under the attack of water and the action of microorganisms. , Degradation tests in aqueous media (containing enzymes such as lipases and cutinases) are one of the most common methods used to determine the biodegradability of polyesters. − Therefore, the biodegradability of PPXThs was evaluated using hydrolysis and enzymatic-catalyzed degradation experiments over a period of 6 weeks, following the same method described in our previous studies. , The weight loss curves of PPXThs degraded in PBS and CALB/PBS solutions are depicted in Figure .…”