Disulfide-Driven On-Demand Degradation of the PBAT Copolymer: Stable Comprehensive Performance, Long-Term Storage, and Redox-Induced Degradation

Common biodegradable polyesters are degraded under favorable conditions, such as industrial compost. Poly(butylene adipate-co-terephthalate) (PBAT) is one of the most prospective and prevalent biodegradable polymer, while its degradation in natural environment is slow. Herein, we introduce a stimulus group with disulfide bonds to obtain a poly(butylene adipate-co-dithiodipropionate-co-terephthalate) (PBADiT) copolyester. Their melting temperature is higher than 120 °C and the thermal stability is sufficient for melt processing. They show high modulus (>110 MPa) and high toughness when ≤30% of disulfide bonds are introduced. BDi (butylene dithiodipropionate) units show slightly lower hydrolysis and enzymatic degradation ability, and PBADiT copolymers show acceptable storage stability in a damp environment. The redox response of PBADiT helps realize on-demand degradation after use. From 0.01 to 1 mol/L H2O2 solutions, the hydrolysis of PBADiT can be regulated or accelerated by 15 days of fast hydrolysis with weight loss exceeding 40%. Reductive conditions, represented by 0.2 mol/L dithiothreitol (DTT) solutions, are also an efficient stimulus source for achieving rapid breakage of PBADiT. Hence, PBADiT copolymers provide a new approach for sustainable and degradable materials with required usage time and impart the polymer with accelerated degradation in redox environments.