Study on hydrophobic property of fast-growing eucalypt wood treated by heat

GAO Wei1,2,LUO Jian-ju1,2*,WANG Guan-yu3,LU Pei1,GUO Xi1,SHI Shi-heng1,LI Rong-ce1(1Forestry College,Guangxi University,Nanning 530004,China;2Guangxi Wood and Wood Products Quality Supervision and Inspection Station,Nanning 530004,China;3Agricultural Science and Technology Information Research Institute,Guangxi Academy of Agricultural Sciences,Nanning 530004,China)

fast -growing eucalypt wood; hydrophobic property; heat treatment; contact angle;partial correlationanalysis

【Objective】This study was performed to improve biological durability of eucalypt wood. 【Method】After the fast-growing eucalypt wood was treated at 180℃ for 1, 2 and 4 h under water vapor, the contact angle and roughness were measured and all the samples were analyzed by FTIR and then their surface features were investigated. The partial correlation among contact angle, treated time and roughness was also analyzed. 【Result】The average contact angle of the untreated wood and the treated wood was 86.57° and above 112°, respectively. With increasing treated time, contact angle was signifi-cantly improved and the change tendency of the contact angle curves became steady and orderly. At 3415.37cm-1,the hydroxy of the hydrophilic functional groups appeared absorption peak and the absorbance of the wntreated wood was 2.22 which decreased to 1.38 after heat treatment for 1 h. The absorbance decreased obviously to 1.34 and 1.30 after heat treatment for 2 and 4 h. At 1618.09 cm-1, the carbonyl of the hydrophilic functional groups appeared absorption peak, and the absorbance of the untreated wood was 0.80 which decreased to 0.72 after heat treatment for 1 h, The absorbanle decreased slightly to 0.66 after heat treatment for 2 and 4 h. The surface of the fast-growing eucalypt wood cracked and distorted at high temperature,which influenced the smoothness of the surfaces. However, there was no clear-cut rules of roughness. The partial correlation coefficient of roughness and contact angle was -0.050 (no-correlation). The partial correlation coefficient of contact angle and treated time was 0.746 (significant correlation). The treated time was related to roughness. 【Conclusion】The fast-grow-ing eucalypt wood increased its hydrophobicity after heat treatment. The decrease of hydrophilic functional groups enhanced its hydrophobic function. Roughness didn’t affect contact angle, so it had nothing to do with hydrophobic function.