Influence of electrochemically deposited TiO2 on the anti-weathering properties of heat-treated wood

Abstract

ABSTRACT Ultraviolet light-induced discoloration is a noticeable issue when heat-treated wood is used outdoors. In this study, titanium dioxide (TiO2) particles were electrochemically deposited on the surface of heat-treated wood via a high-voltage electrostatic field (HVEF). Natural and artificial weathering tests were carried out to evaluate the anti-weathering properties after the electrochemical deposition. During HVEF treatment, Ti particles were triggered in the form of Ti4+. Ti4+ grafted with the hydroxyl groups of hemicellulose and lignin in the form of Ti–OH, and TiO2 was produced due to the oxidizing atmosphere generated by HVEF. TiO2 and Ti–OH played roles as UV absorbers, reducing degradation and discoloration of heat-treated wood. The photodegradation of lignin was alleviated effectively during both the artificial and natural weathering. The stability of wood color was remained. After the artificial weathering, the values of L*, a* and b* of the electrochemical depositied sample were 55, 10 and 25, respectively. The leaching amount of TiO2 after artificial or natural weathering was less than 6% or 40%, respectively determined by atomic absorption spectroscopy. The results suggest the feasibility of the electrochemical deposition of TiO2 for improving the anti-weathering properties of heat-treated wood and provide an effective strategy for industrial wood modification.