Abstract:

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^-1and 35.52 mN·m^-1each), 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.

Key words: Chinese Fir, Poplar, Surface free energy of wood, Surface chemical functional group of wood