Recyclable polythioesters and polydisulfides with near-equilibrium thermodynamics and dynamic covalent bonds

The accumulation of discarded petroleum-based plastics causes serious environmental crises. Currently, recyclable polymers with neutrality in thermodynamics, such as polyesters, polycarbonates, and polyolefins, have been developed as promising alternatives to traditional petroleum-based polymers. However, the chemical recycle of these polymers usually requires high energy input and expensive catalysts. Dynamic covalent bonds, such as thioester and disulfide bonds, have emerged as building blocks for constructing recyclable polymers that can be rapidly degraded/recycled under mild conditions. In this review, we introduce representative studies on recyclable polythioesters and polydisulfides with respect to their synthetic strategies, thermodynamic manipulation, physicochemical properties, and preliminary applications. We also highlight the important role of kinetic factors played in the design of recyclable polymers. Finally, major challenges, perspectives, and future opportunities in the synthesis and applications of polythioesters/polydisulfides are discussed.