高温热处理速生桉木材的疏水性能研究

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

【目的】揭示速生桉木材的疏水原因,提高速生桉木材的生物耐久性。【方法】速生桉木材分别经180℃水蒸汽热处理1、2和4h后,测量接触角、粗糙度,进行FTIR分析、观察表面形貌特征,并对接触角、处理时间和粗糙度进行偏相关分析。【结果】未处理速生桉锯材表面接触角均值为86.57°,热处理锯材表面接触角均在112°以上。随着热处理时间的延长,接触角显著提高,接触角曲线变化趋于平稳有序。亲水官能团羟基在3415.37cm-1处出现吸收峰,未处理材的峰值吸光值为2.22,热处理1h后吸光值显著下降至1.38,热处理2和4h分别降低至1.34和1.30,降幅明显。亲水官能团羰基在1618.09cm-1处出现吸收峰,未处理材的峰值吸光值为0.80,热处理1h后,吸光值轻微下降至0.72,热处理2和4h后均为0.66,下降不再明显。速生桉木材在高温状态下表面发生开裂、扭曲等,影响了表面的平整度,但粗糙度变化并无显著规律。粗糙度与接触角净相关系数为-0.050,完全不相关;接触角和处理时间偏相关系数为0.746,显著相关;处理时间和粗糙度低相关。【结论】经180℃水蒸汽热处理后速生桉木材粗糙度与接触角变化无相关性,热处理时间对接触影响显著,热处理温度的提高会啬粗糙度,但不影响木材的疏水性能。

[ 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 FFIR 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 significantly 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 de- creased 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 tor 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 （nocorrelation）. 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.