熏蒸处理对落叶松木材颜色和力学强度的影响

为研究熏蒸处理对木材颜色和力学性能的影响，采用氧硫化碳(COS)、溴甲烷(MB)和硫酰氟(SF)分别在3种不同质量浓度下对落叶松材进行熏蒸处理，用色差分析、力学性能测试、电子扫描电镜(SEM)、能谱分析(EDS)和红外光谱分析(FTIR)对熏蒸前后木材的物理力学性能和官能团变化进行表征。结果发现:1)使用3种熏蒸剂处理后，落叶松材的颜色均发生明显变化，其中COS熏蒸处理对试样的明度(L*)、红绿轴色度指数(a*)的影响最小；2)落叶松材经过COS熏蒸处理后，顺纹抗压强度、静曲强度、弹性模量均下降，其中顺纹抗压强度下降最明显，在熏蒸剂质量浓度为124.2 g/m3时，顺纹抗压强度下降幅度达13.09%，而静曲强度和弹性模量分别下降9.38%、8.66%；经MB、SF熏蒸处理后，试样的顺纹抗压强度、静曲强度、弹性模量均无明显变化；3)熏蒸后的落叶松材表面微观结构未发生明显变化，但COS熏蒸后木材表面的S元素和SF熏蒸后木材表面的F元素分布密度均有所增加；4)在落叶松红外光谱图中，经MB、SF熏蒸后，碳氧双键和碳氢键明显增多；COS熏蒸后，半纤维素上的碳氧双键伸缩振动减弱，芳香环骨架上的碳氧双键的伸缩振动加强，木质素相对含量增加。 

Effects of fumigation treatment on wood color and mechanical strength of Larix gmelinii

In order to study the influence of fumigation processing on wood color and mechanical properties of wood, three kinds of fumigants ( carbonyl sulfide, COS; methyl bromide, MB; sulfuryl fluoride, SF) were used to process larch ( Larix gmelinii ) in three different mass concentrations, and the color difference detection, scanning electron microscope ( SEM) , energy dispersive spectrometer ( EDS) and Fourier transform infrared ( FTIR) spectroscopy were used to analyze the fumigation treatment influence on physical and chemical properties of larch samples. The results showed that:1) larch wood color was altered obviously after fumigation treatment, and COS fumigation treatment had minimal impact on brightness ( L*) , red and green chromaticity index ( a*) . 2 ) After COS fumigation treatment, the compression strength parallel to the grain, the bending strength and the elastic modulus of samples decreased significantly, and compressive strength had the greatest reduction at condition of mass concentration at 124. 2 g/m3 , decreased by 13. 09%, and the bending strength and the elastic modulus of samples fell by 9. 38% and 8. 66%, respectively. After MB fumigation and SF fumigation treatment, the compression strength parallel to the grain, the bending strength and the elastic modulus of samples hardly changed. 3) After fumigation processing, the surface microstructure of samples was maintained, but the surface S and F element distribution slightly increased after COS and SF fumigation treatment. 4) In the infrared spectroscopy of larch wood, =the C O and C—H bonds increased after MB and SF fumigation processing. After COS fumigation processing, =the C O stretching vibration of hemicellulose became weakened, =but the C O stretching vibration of aromatic ring skeleton became stronger, and the content of lignin increased.