Transparent and Thermoplastic Silicone Materials Based on Room-Temperature Diels–Alder Reactions

A chemoenzymatic synthesis was used in the production of translucent silicone material with Diels–Alder cross-links. The exploration of a library of diene and dienophile combinations yielded materials that were initially cured in 5 h at room temperature and that could be repaired in <5 min with a relatively low-temperature regimen (heat to 80 °C and cool to room temperature to cure). All of the synthesized materials were thermoplastic and could be remolded while effectively retaining the bulk properties of the parent material (e.g., translucency, tensile strength, hardness, etc.). The healed "scars" of the materials were quite robust, with subsequent catastrophic failure during elongation of repaired materials occurring outside of these locations. To the best of our knowledge, this is the first and only reported case of a cross-linked silicone material based on the Diels–Alder reaction, where curing of the silicone material occurs at room temperature.