Tung oil improves dimensional stability of flattened bamboo

Abstract

Flattened bamboo has a higher material utilization rate and a lower content of adhesives, which exhibits enhanced stiffness and anti-hygroscopicity, compared with original bamboo. To promote flattened bamboo to be an engineering material, the dimensional stability of flattened bamboo is required to be further improved. In this study, natural tung oil was used to modify flattened bamboo under different temperatures (23–160 °C). It was found that the water-swelling and shrinkage of the flattened bamboo reduced more than 43.00% and 20.93%, respectively, after modification with tung oil at 160 °C. The tung oil film was identified to adhere to the cell lumen, intercellular space, cell wall layer and pit channel. Furthermore, many pits in vessels were shrunk, and the crystallinity of cellulose was increased during modification of flattened bamboo by tung oil treatment at 100–160 °C. Altogether, these findings suggest that tung oil improves the dimensional stability of flattened bamboo by delaying water transport in the transverse direction and retarding the bonding of water molecules to the cell wall. Additionally, tung oil modification has little impact on the visual effects of flattened bamboo.