High-performance and recyclable silicone rubber vitrimer composites via dual crosslinking of dynamic boronic ester bonds and interfacial hydrogen bonds

The recycling of thermosetting silicone rubber has seen significant advancements through the elaborate design of molecular structures. However, challenges persist in achieving effective recycling via industrially viable methods. In this work, we developed high-performance and recyclable silicone rubber, specifically polymethylvinylsiloxane (PMVS)-based vitrimers (PBVs), using melt processing. Dual-crosslinking interactions were constructed between PBVs and silica nanoparticles, combining dynamic covalent boronic ester bonds and hydrogen bonds. The PBVs exhibited high mechanical performances with tensile strength ( σ ) up to 3.65 MPa, elongation at break ( ε ) up to 1350 %, and tensile toughness ( U T ) up to 25.11 MJ/m 3 , superior to those reported silicone rubber vitrimers. Furthermore, the presence of boronic ester bonds enabled efficient thermal reprocessability, attributed to the low activation energy of dynamic bond exchange, which ranged from 13.51 to 27.64 kJ/mol for the samples examined. The material demonstrated the ability to undergo multiple reprocessing cycles with minimal loss of performance, maintaining σ of 3.49 MPa, ε of 850 % and U T of 12.88 MJ/m 3 after three times of reprocessing. By simultaneously enhancing the mechanical properties and recyclability of silicone rubber using an industrially scalable technique, the work offered a promising pathway for real-world recycling of thermosetting rubber materials.