The use of microwave system to deposit TiO2 particles on wood surface to improve water repellency

The objective of the present study is to modify the surface of Pinus elliottii wood by means of the deposition and impregnation of TiO2 particles synthesized through the microwave-assisted solvothermal method. Initially, TiO2 nanoparticles were obtained from titanium isopropoxide in alcohol at 140°C, for 60 min, through a reaction cell coupled to an adapted microwave system. liottii samples were added to TiO2 rich solution after the synthesis and, once more, subjected to microwave solvothermalization process at 90°C for 60 minutes and self-generated pressure 3-bar. The X-ray Diffraction evidenced that the nanostructures observed through Scanning Electron Microscopy corresponded to the anatase crystalline phase. Particles in agglomerates formed a homogeneous cover on the surface, it is likely that there was interaction through hydrogen bonds with the OHradicals found in wood cell walls. The microwave action makes molecules prone to align due to electric field influence, fact that makes it possible having an oriented and uniform deposition on the surface and its impregnation into the wood. In addition, the hydrophobicity measured through sessile drop analysis showed that the adopted method was capable of turning the original wood surface from hydrophilic into hydrophobic. The treated samples that were immersed in water for 400 hours showed significant water absorption delay, therefore the method proved effective to modify the surface structure of the wood, fact that gives it special features to increase its durability and stability