利用X射线衍射技术与红外光谱分析真菌侵蚀的木材

Analysis of Decayed Wood by Fungi with X-Ray Diffractometry and Fourier Transform Infrared Spectroscopy

为了弄清真菌侵蚀木材的微细结晶构造与主成分官能团的变化,利用X射线衍射技术和红外光谱研究了分别经过黄孢原毛平革菌(PC)和棉腐卧孔菌(PP)侵蚀不同时间后毛白杨木材的结晶度、晶胞内层间距、晶粒宽度和主成分官能团的变化情况。结果表明:(1)PC与PP的侵蚀对木材纤维素结晶区的晶格构造没有影响,纤维素结晶区衍射2θ角和层间距基本保持不变,但纤维素结晶度和晶粒宽度随侵蚀时间增加而呈减小的趋势,并且受PP侵蚀的要比受PC侵蚀的明显,表明PP侵蚀对纤维素的破坏程度要大于PC侵蚀;(2)半纤维素在侵蚀过程中其木聚糖被不同程度的降解,使得产物中羰基含量增加,PC与PP对半纤维素的降解效果与纤维素几近相同;(3)木质素受PC侵蚀后苯环被氧化裂解生成链烃,而受PP侵蚀的变化不明显。

In order to make clear the changes in the micro crystal structures of celluloses and the functional group of main components including cellulose,hemicelluloses and lignin in wood decayed by fungi,the crystallinity,layer spacing d in crystalline unit cell,width of crystallite and functional group of main components of Populus tomentosa Carr wood,which was decayed by Phanerochaete Chysosporium （white-rot） and Postia Placenta （brown-rot） with various durations,for two weeks,four weeks,six weeks,eight weeks and ten weeks,respectively,were investigated by means of X-ray diffraction and FTIR spectroscopy methods.It was concluded that the lattice structures of crystallite in wood cellulose were not destroyed by PC and PP,and the two theta angles and layer spacing d in crystallite were constant,although the decaying treatment times were different for each other when decayed by the same fungi.However,the crystallinity and width of crystallite decreased with the decaying treatment times increasing,and the decaying effects by PP were more significantly than those by PC,which showed that the damage extent of celluloses decayed by PP was greater than that by PC.It was estimated that the xylan in hemicelluloses had been degraded to various extents with the process of decaying in wood,resulting in the carbonyl content increasing,and the effects of degradation on hemicelluloses and celluloses by PC and PP were almost the same.Furthermore,benzene rings in lignin,which had no remarkable changes by PP,were oxidized into chain hydrocarbon after decaying by PC.