Cationically Polymerized Epoxy and Radiation-Cured Acrylate Blend Nanocomposites Based on WS2 Nanoparticles Part B: Mechanical and Physical Properties

Abstract

The radiation curing paradigm of opaque WS2 nanoparticle (NP)-based epoxy/acrylate nanocomposites was studied and found to exhibit both a reduction in viscosity and an enhanced degree of curing when incorporating WS2 NPs. The objective of this study was to investigate the mechanical, thermal, and physical properties of a radiation-induced and cured epoxy/acrylate blend containing 0.3 to 1.0 wt.% WS2 NPs. Experimental results indicate that the tensile toughness increased by 22% upon optimizing the NP content compared to that of WS2-free formulations. Tensile fractured surfaces with different WS2 NP contents were analyzed with a scanning electron microscope and an atomic force microscope and showed distinctive morphology depending on the WS2 NP content, supporting the results of the tensile test. The energy required to break shear adhesion specimens demonstrated an increase of up to 60% compared to that of the neat resin. The glass transition temperature determined by dynamic mechanical analysis presented similar or higher values upon WS2 NP incorporation. Furthermore, up to 80% improvement in impact strength was demonstrated when WS2 NPs were dispersed in the epoxy/acrylate blend. It was concluded that the surface chemistry and dispersion level of the WS2 NPs are the major variables affecting the macro properties of cationically radiation-cured resins and their adhesion properties. This study is the first to demonstrate the possibility for radiation-induced curing of opaque NPs based on WS2 that serve as both a reinforcement nanoparticle at low concentrations and an enhancement of the degree of curing.