Effects of Tung oil treatment on wood hygroscopicity, dimensional stability and thermostability

Abstract

It is commonly known that wood is a limited renewable material, and its low dimensional stability characteristics limit its ability to be more widely used. Tung oil, which is characterized by environmentally friendly and water-repellent features, is used in this study as a modifier to improve the properties of wood. Wood is impregnated with Tung oil at room temperature, and the effects of Tung oil on the dimensional stability, moisture absorption, chemical structure, thermostability, and morphological characteristics of the wood are studied. The results show that Tung oil treatment is an effective technique to improve wood dimensional stability. The weight percentage gain was found to attain up to 60.56%, and Tung oil treatment decreased the wood tangential and radial swelling coefficients by 30.8% and 29.6%, respectively. Tung oil treatment also decreased the moisture absorption by 51.53%. Specimens treated with Tung oil presented two sharp peaks of decomposition around 376 °C and 421 °C, while the control specimens exhibited a more common DTG curve with a sharp peak at 376 °C. Tung oil can be impregnated into wood and occluded pits, and solidifies at the internal surface of wood to prevent moisture absorption. This method can be implemented in buildings, furniture, and landscape architecture to broadly expand the application of wood products.