Improvement of UV resistance of wood surfaces by using ZnO nanoparticles

Nanoparticles of some of the inorganic metal oxides are known to absorb UV radiation. In this study, the UV resistance of rubberwood (Hevea brasiliensis) coated with zinc oxide (ZnO) nanoparticles dispersed in maleic anhydride modified polypropylene (MAPP) was evaluated. The photostability of nano ZnO blended polyurethane (PU) exterior clear coating was also evaluated. The rubberwood specimens treated/coated with nanoparticle blended MAPP and PU coatings were exposed to xenon light source in a weather-o-meter. The colour and chemical changes on exposed wood surfaces were analyzed. The coatings without nanoparticles exhibited photo-yellowing and degradation of wood surfaces due to UV light exposure. Dispersion of ZnO nanoparticles in MAPP and PU coatings restricted the colour changes and photodegradation of wood polymers.