Accelerated Photocuring of Acrylate Resins with WS2 Nanoparticles

Radiation curing (photocuring) of thermosetting polymers, such as acrylate resins, is a common technology with diverse applications, such as in adhesives, coatings, advanced manufacturing, medical-related technologies, and more. Photocuring of acrylate thermosets is initiated via a radical-induced cleavage of a photocuring agent, like bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (BAPO), which activates the vinyl C=C double bond of the acrylate moiety. Here, we show that addition of semiconducting WS2 nanoparticles (NPs) accelerates the photocuring process. Using electron paramagnetic resonance (EPR) of ethanol-water solutions, the mechanism of the radical reactions of BAPO and WS2 NPs is investigated. It is found that the two photocuring agents operate according to entirely different mechanisms, which has been discussed in great detail. In contrast to BAPO, which is photocleaved during the curing process, the WS2 NPs remain unchanged, leading to major mechanical reinforcements of the cured acrylate film.