Design and Synthesis of Co‐initiators via Base‐Catalysed Sequential Conjugate Addition: Application in Photoinduced Radical Polymerisation Reaction

Abstract

Applications of photochemistry are becoming very popular in modern‐day life due to its operational simplicity, environmentally friendly and economically sustainable nature in comparison to its thermochemistry. In particular photoinduced radical polymerisation (PRP) reaction is finding more biological applications and especially in the areas of dental restoration process, tissue engineering and artificial bone generation. Type‐II photoinitiator and co‐initiator promoted PRP turned out to be a cost effective protocol, and herein we report the design and synthesis of a new efficient co‐initiator for PRP reaction via barrierless sequential conjugate addition reaction. Experimental mechanistic observations were further complemented by computational data. Time for newly synthesised 1,2‐benzenedithiol (DTH) based co‐initiator promoted polymerisation of diurethane dimethacrylate (UDMA, 70%) and triethylene glycol dimethacrylate (TEGDMA, 30%) in presence of 450 nm LED (15 W) under the aerobic conditions was 38 seconds. High glass transition temperature, improved mechanical strength (860 BHN) and longer in‐depth polymerisation (3 cm) was observed.