Cross-Linked Poly(carbosiloxane) (cPC₂SO): A depolymerizable silicone platform for closed-loop Recycling and 3D Printing

Silicone elastomers are widely utilized in diverse applications owing to their flexibility, biocompatibility, and long-term stability. However, conventional silicone materials are typically based on permanently crosslinked networks, which severely limits their recyclability and contributes to environmental waste. In this work, a chemically recyclable silicone elastomer based on crosslinked poly(carbosiloxane) (cPC₂SO) was developed through a straightforward synthetic strategy. The incorporation of two carbon atoms within the polymer backbone provided enhanced softness and extensibility while maintaining network integrity. More importantly, the elastomer could be selectively depolymerized into recoverable monomer species and subsequently repolymerized, enabling closed-loop material recycling. The depolymerization process also allowed efficient recovery of silicone components from mixed plastic waste streams, offering a practical route toward circular silicone materials. Building upon this recyclable platform, photocurable resin formulations were further developed for digital light processing (DLP) 3D printing. Successful fabrication of three-dimensional structures demonstrates the potential of cPC₂SO-based systems as sustainable silicone materials that combine mechanical performance, chemical recyclability, and additive manufacturing capability.