Photo-stabilization properties of transparent inorganic UV-filter/epoxy nanocomposites

Transparent inorganic UV-filter/epoxy nanocomposites with high photo-stabilization properties were reported in this paper. First, inorganic UV-filter ZnO, core-shell structural silica-titania (S-T) and silica-titania-silica (S-T-S) nanoparticles were synthesized. Transparent inorganic UV-filter/epoxy (ZnO/epoxy, S-T/epoxy and S-T-S/epoxy) nanocomposites were subsequently prepared from the transparent epoxy and the as-prepared nanoparticles via in situ polymerization method. Optical properties of inorganic UV-filter/epoxy nanocomposites, namely visible light transparency and UV-light shielding efficiency, were studied using an UV-Vis spectrophotometer. The photo-stabilization properties of inorganic UV-filter/epoxy nanocomposites were examined by the light-emitting diode (LED) lifetime test. The results showed that the photo-stabilization effect of inorganic UV-filter on the lifetime of LED lamp obeys the following sequence: ZnO > S-T-S > S-T. Compared with the UV LED lamps encapsulated with pure epoxy, the lifetime of UV LED lamps encapsulated with ZnO/epoxy, S-T-S/epoxy and S-T/epoxy nanocomposites has been improved by 76%, 54% and 33%, respectively. (C) 2007 Elsevier Ltd. All rights reserved.