远红外对木材穿透特性的研究

STUDY ON WOOD FAR INFRARED PENETRABILITY

根据福建22种主要用材树种远红外光谱分析,多数树种,对木材穿透深度最大的远红外波数在1840cm^(-1)(波长5.43μm)附近。22种树种木材进行远红外穿透深度测定,穿透深度最大的是山槐弦向,0.71mm;最小的是罗木石楠径向,0.135mm。远红外对木材的穿透深度弦向大于径向,且与木材的密度、含水率有关。木材对远红外的吸收遵守朗伯定律,但吸收系数径向比弦向大。本文还根据木材远红外光谱分析提出木材纤维素、木素远红外吸收,主要是分子含氧基团等键链间的振动吸收。这些为木材远红外干燥及其机理研究提供科学依据。

On the basis of analysing far infra-red spectra of 22 major tree species of Fujian, for most tree species, the far infra-red radiation which caused the maximum depth of penetration in wood was around 1840 cm^(-1) wave number (5.43μm wave lenth) . Having measured the depth of far infra-red penetration of 22 tree species, we learent that the maximum one was in the tangetial section of 'Albizzia kalkora' 0.71 mm; and the minmum one was in the radial section of 'Photinia davidsonia' 0.135 mm. We also learnt that depth of the penetration was deeper in tangetial section than in radial section and it varied with the density and moisture content of the wood. The law of wood absorbing the far infra-red radiation corresponded with the Lambert's law of absorption, but the coefficient of absorption was larger in radial section than in tangetial section. According to analysing far infra-red spectra, we suggested that the absorption of wood cellulose and lignine unit is mainly caused by the vibration of the equivlent chains of molecular oxygenic group. These results offered a scientific basis for the study of the fundamentals of wood far infra-red drying.