Thermally self-healing silicone-based networks with potential application in recycling adhesives

Abstract

A simpler approach is developed to obtain recyclable self-healing polysiloxane networks based on the thiol-ene reaction and Diels–Alder (DA) reaction. Tetramethyltetravinylcyclotetrasiloxane (D₄^Vi) was first modified with furan via a thiol-ene reaction, giving furan-functionalized cyclotetrasiloxane (D1). D1 then reacted with bismaleimide to form thermally dynamic reversible crosslinking linkages via a Diels–Alder (DA) reaction. Thus, crosslinked networks (CNs) were synthesized and their depolymerization through the retro-DA reactions was thoroughly studied. The kinetics of the DA reaction was studied by ¹H-NMR spectroscopic analysis of the model compounds. Results indicated that the DA reaction performs better at 60 °C and follows second-order kinetics. The CNs show strong photoluminescence when irradiated by UV light and exhibited potential application in recyclable adhesives for glass.