Decay resistance of rubberwood (Hevea brasiliensis) impregnated with ZnO and CuO nanoparticles dispersed in propylene glycol

- Stable dispersions of ZnO and CuO nanoparticles were prepared in propylene glycol.
- Nano-dispersions were characterized using UV-Vis. absorption spectroscopy and Dynamic Light Scattering analysis.
- Nano dispersions inhibited white-rot (Trametes hirsuta) and brown-rot (Polyporus meliae) decay effectively.
- Nano-dispersions treated wood specimens showed slight reduction in equilibrium moisture content.

Efficacy of nanoparticle is essentially influenced by the medium in which it is dispersed, the size of the particles in dispersion and the stability of dispersion. The major constrain in dealing with nanoparticle dispersion can be resolved by identifying a proper dispersive medium. In the present study, dispersions of zinc oxide and copper oxide nanoparticles was prepared in propylene glycol (PG). Dynamic light scattering analysis showed that particles remained in nano size without formation of aggregates. UV-vis. absorption spectroscopy showed that the nano-dispersion in propylene glycol is stable without adding any additional surfactants or dispersive agents. Fungal decay and moisture adsorption of rubberwood (Hevea brasiliensis Muell Arg.) specimens impregnated with nano-ZnO and nano-CuO dispersion in PG was evaluated. Dispersion of ZnO and CuO nanoparticles in PG inhibited white-rot (Trametes hirsuta) and brown-rot (Polyporus meliae) decay effectively. The changes observed in FTIR spectra and SEM further support the results. Nano-dispersions treated specimens showed some reduction in moisture adsorption with lower equilibrium moisture content values as compared to untreated wood.