Epoxy acrylate polymeric films, effect

Acrylated epoxy systems undergo significant changes in thermomechanical properties on standing at room teinperature. Other studies have shown that free radicals are very long-lived in UV-cured systems kept under inert atmospheres, amd that polymerization can continue for extended periods due to the low mobility of the residual unsaturated species at higher conversions. In this study, however, the films were exposed to air immediately after irradiation, which should effectively quench the residue free radicals. 

In situ polymerization of ZnO dispersions in acrylic monomers, epoxy, or vinylester resins resulted in transparent nanocomposite films and bulk materials. A UV-vis transmission spectmm of a ZnO/PBDMA nanocomposite is displayed in Figure 12, showing the high transparency in the visible and the steep UV-absorption band at wavelength <360 nm. Even low concentrations (<0.1%) of ZnO nanoparticles cause a significant UV-shielding effect. 

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