杨木和杉木木材表面性质的研究

Study on the Surface Properties of Poplar and Chinese Fir Wood

以人工林杨木和杉木木材为研究对象 ,对其表面自由能、表面极性和表面化学官能团等木材表面特征因子进行测定 ,并探讨不同温度处理条件下木材表面特性的变化机理。研究结果表明 :杉木比杨木有较高的总表面自由能 (42 35mN·m- 1 对 38 93mN·m- 1 )和非极性表面自由能 (41 6 1mN·m- 1 对 35 5 2mN·m- 1 ) ,而杨木的极性表面自由能比杉木要高 (3 4 1mN·m- 1 对 0 74mN·m- 1 )。杨木和杉木木材经过不同温度处理后 ,其总表面自由能和非极性表面自由能都随着处理温度的升高而下降 ,而极性自由能则有不同程度的升高。产生此种现象的原因主要为木材表面羟基缔合状态的解除及表面脱羟基作用的综合结果。木材表面 3种主要化学官能团为羟基、烷基和缩醛基 ,在高温处理条件下 ,两种木材羟基对烷基和缩醛基吸收峰面积之比都有所下降 ,说明高温处理过程是一个使木材表面羟基密度减少的过程。木材表面自由能与木材表面化学官能团变化有明显的相关性。

Two tree species wood planted in China, Poplar and Chinese Fir, were chosen as the research materials. The wood surface properties, e.g. the surface free energy, the surface polarity, the surface chemical function groups and the influence of temperature on the wood surface properties, as well as the relationship between the wood surface properties and surface chemical function group were studied. The results revealed that Chinese Fir had higher surface free energy (42.35 mN·m -1) and dispersive surface free energy (41.61 mN·m -1) than that of Poplar (38.93 mN·m -1 and 35.52 mN·m -1 each), but the polarity surface free energy of Poplar (3.41mN·m -1) was higher than that of Chinese Fir (0.74 mN·m -1). The total surface free energy and dispersive surface free energy of Poplar and Chinese Fir decreased with the temperature increasing of treatment resulted from the comprehensive effect of the change of hydroxide and the de-hydroxide of the wood surface. The three function groups of wood surface were hydroxide, alkyl and aldehyde. The ratio of hydroxide to alkyl and hydroxide to aldehyde decreased the wood was treated in high temperature, which imdicated that the process of de-hydroxide was a process of hydroxide density decreasing on wood surface. There was an obvious correlativity between surface free energy of wood and the change of chemical functional group on wood surface.