Tailoring the interface of WS2 nanoparticles by photo-initiator for radiation curing and reinforcement of nano-structured acrylates

Abstract

Surface modification of tungsten disulfide (WS2) nanoparticles (NPs) by a photo-initiator (PI) for radical curing of acrylate nano-structured systems has been studied with the purpose of acquiring covalent bonding of the acrylate matrix to the NPs surface. This surface functionalization was expected to photosensitize both the PI and the NPs thereby enhance the photocuring of the acrylate as well as improving its mechanical properties. The studied PI was the commonly used Bis(acyl) phosphane oxides (BAPOs). For surface modification of the WS2 NPs, the BAPO was functionalized first with Tri(methoxy) silane (TMESI) to yield TMESI-BAPO moieties. Subsequently, the functionalized BAPO was chemisorbed to the WS2 NPs resulting in WS2 NPs surface modified by TMESI-BAPO pendant moieties. The functionalization and surface modification were confirmed using spectroscopic techniques as well as electron microscopy, and thermal measurements. Thermal gravimetric analysis (TGA) displayed 40 wt% weight loss for TMESI-BAPO modified WS2 upon heating to 400 °C. The modified WS2 NPs were incorporated into acrylate resin to study the curing kinetics and resulting mechanical properties compared to neat WS2. Nanostructured acrylate with TEMSI-BAPO modified WS2 NPs exhibited an increase of 83% in storage modulus and toughness compared to neat acrylate.