Reprocessable Silyl Ether-Based Dynamic Covalent Poly(dimethylsiloxane) Networks with Superb Thermal Stability and Creep Resistance
Siyuan Chen, Jie Cao, Junping Zheng
Abstract
Introducing covalent adaptable networks (CANs) into polydimethylsiloxane (PDMS) elastomers is an effective approach to solving the recycling issue of thermoset PDMS materials. However, CANs generally exhibit favorable dynamic properties to achieve efficient recycling, which leads to poor thermal stability and creep resistance. Herein, we successfully constructed dynamic silyl ether-based networks within the PDMS system by incorporating thermally stable silyl ether linkages, resulting in reprocessable PDMS elastomers with excellent mechanical properties, remarkable thermal stability, and desirable creep resistance. Compared with the samples without silyl ether-based networks, the prepared PDMS elastomer presented a 70 °C increase in T 50 (the temperature at 50% weight loss), reaching as high as 635 °C. Meanwhile, after 10 reprocessing cycles, the mechanical properties of the prepared elastomer can still be almost completely restored, demonstrating superior reprocessability. More importantly, owing to the thermal stability of silyl ether-based networks, the prepared PDMS elastomer exhibited a desirable creep resistance at 120 °C. Therefore, the rational construction of dynamic silyl ether-based networks within the PDMS system can achieve an effective balance between thermal stability and recyclability.