► γ-trimethoxy silyl propyl methacrylate was used for surface modification of TiO2 and SiO2 nanoparticles. ► Styrene acrylonitrile copolymer with TiO2, SiO2 and nanoclay were impregnated into Simul wood. ► Thermostability of wood polymer composite was improved. ► The mechanical behavior of wood was markedly improved on treatment. ► TiO2 incorporation enhanced UV stability of wood composite.