Chemically Closed-Loop Recyclable High-Strength Aliphatic Polycarbonate: Controlled Ring-Opening Polymerization, Kinetics, and Thermodynamics
Junxiang Dai, Hang Li, Ke Liu, Runsong Zhang, Si‐Chong Chen, Guoqiang Tian, Gang Wu, Yu-Zhong Wang
Abstract
The development of chemically recyclable polymers with useable performance represents a highly promising solution to the challenges associated with end-of-use plastics. In this work, we report a controlled synthesis of chemically closed-loop recyclable aliphatic polycarbonate through “living” ring-opening polymerization (ROP) of gem-disubstituted cyclic carbonate, i.e., 5,5-dimethyl-1,3-dioxan-2-one (DTC), featuring a high molecular weight (up to 260 kDa) and a narrow polymer dispersity index ( D̵ < 1.30). Systematically kinetic and thermodynamic studies of DTC’s ROP under both solution and bulk conditions are carried out to obtain the ceiling temperature ( T c ) of DTC. In addition, melting point ( T m ), crystallization temperature ( T cryst ), initial decomposition temperature (T 5% ), and maximum decomposition temperature ( T max ) of PDTC can be tailored in the wide ranges of 100–120 °C, 73–117 °C, 224–307 °C, and 271–332 °C, respectively, which shows that good control of molecular weight and the desirable mechanical properties can be achieved, with a tensile strength of up to 80.0 ± 2.0 MPa. Significantly, highly efficient recovery of PDTC to DTC is achieved, with a yield of 99.3% and a purity of 99.1%, highlighting an excellent closed-loop recyclability of PDTC. These results demonstrate the potential for use of PDTC as a sustainable and high-performance polymer.