热处理过程中杉木压缩木材的材色及红外光谱

为了探讨热处理过程中杉木压缩木材的材色变化规律 ,以及材色和木材化学主成分变化之间的关系 ,该研究测定了空气介质和真空中热处理杉木压缩木材 (热处理温度范围 140～ 2 2 0℃ ,时间范围 0～ 36h)的明度 (L )、色差 (ΔE )以及红外光谱 .同时测定了杉木压缩木材的回复率 ,无压缩对照试材的重量损失率和抗收缩率 .该研究的结论为 :①在相同条件下 ,随着热处理时间延长 ,木材明度减小 ,色差增大 ;空气介质中热处理和真空中热处理相比 ,在处理温度和时间相同的情况下 ,前一种方法处理后的木材明度更小 ,色差更大 .②就热处理过程中木材明度、色差与回复率之间的关系而言 ,两种热处理方式之间的差异不大 ;热处理中木材变定的固定程度与木材颜色的变化程度有关 .③就热处理过程中杉木压缩木材的明度、色差与对照试材的重量损失率、抗收缩率之间的关系而言 ,重量损失率或抗收缩率越大 ,对应的杉木压缩木材的明度越小 ,色差越大 .④红外吸收光谱表明 ,在热处理过程中波数在 1743,16 6 0和 16 0 5cm-1附近的羰基 (C =O)峰的变化趋势最为明显 ,说明在热处理固定杉木压缩木材的过程中 ,至少半纤维素 ,甚至木素发生了化学变化 .

Change of brightness, chromatism and infra red spectra of compressed China fir wood during heat treatment

In this study the brightness, chromatism and infra red spectra ofcompressed China fir wood during heat treatment in air or heat treatment in vacuum are studied. The water-saturated and boiled specimens of China fir （Cunninghamia lanceolata） are hot pressed with the average compression rate of 50%. Then they are heat treated in a common oven or in a vacuum oven, with the temperatures of treatment of 140，160，180，200，220℃, respectively. Then the brightness, chromatism, infra red spectra of the specimens are measured and discussed. In addition, some relationships between brightness, chromatism and recovery, weight loss and anti-swelling efficiency are deduced and discussed. The results are: (1) The brightness of the specimens will decrease and the chromatism will increase with the prolongation of time of heat treatment. Compared to heat treatment in vacuum, the specimens have less brightness and more chromatism after being heat treated in air, under the conditions of same temperature and time of heat treatment. (2) As far as the relationships between brightness, chromatism and recovery are concerned, there is little difference between heat treatment in air and heat treatment in vacuum. The fixation degree of compression set is closely related to the change degree of color. (3) As far as the relationships between brightness, chromatism and weight loss, anti-swelling efficiency are concerned, the more the weight loss or anti-swelling efficiency is, the less the brightness is, or the more the chromatism is. (4) The infra red spectra of specimens show that there are evident changes of waves at the wavelength of 1743, 1660 and 1605cm-1 which are attributed to the change of C=O in wood. So it is clear that at least hemicellulose, even lignin in wood cell chemically changes during heat treatment of compressed wood of China fir.