碳化温度对应压木细胞结构与化学成分的影响  

Effect of carbonization temperature on cell structure and chemical composition of compression wood

作　　者：代博仁 石江涛 刘星 夏重阳 DAI Boren;SHI Jiangtao;LIU Xing;XIA Chongyang(College of Materials Science and Engineering,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学材料科学与工程学院,南京210037

出　　处：《林业工程学报》2022年第4期52-57,共6页Journal of Forestry Engineering

基　　金：江苏省林业科技创新与推广项目(LYKJ[2020]20)。

摘　　要：以樟子松的应压区和对应区木材为原料,探究碳化温度对两者结构与化学成分的影响,为应压木在炭材料领域的应用提供理论基础。利用高温管式炉在氮气保护下碳化,设置220,375,600和900℃4个温度,计算两类木材的碳化产率,并采用扫描电镜、红外光谱和X射线衍射仪研究细胞壁结构、化学官能团和晶体结构在不同碳化温度下的变化。应压木炭材料产率高于对应木,碳化产率随碳化温度升高而降低;375℃时应压木出现细胞收缩和局部破裂,而对应木则表现为较为光滑的炭材料断面;900℃时应压木细胞壁破裂严重,细胞壁上出现类似微晶的颗粒状物质,对应木细胞收缩明显且细胞间隙增大,但还保持细胞结构。红外光谱显示,在低于375℃时两类木材均出现半纤维素和纤维素的热降解,木质素骨架结构也发生变化。随着碳化温度的升高,木质素苯环骨架降解重构,有石墨化趋势。X射线衍射分析表明:220~375℃时木材组织中的晶体结构被破坏,600~900℃时出现新的晶体构型。应压木与对应木对于碳化温度的响应是不同的。碳化过程中,应压木更容易出现细胞收缩、细胞间隙增大、细胞壁破裂等,有利于制备规则序态结构和石墨化的炭材料。The compression wood and opposite wood of Pinus sylvestris var. mongolica Litv. were used to investigate the effect of carbonization temperature on cell structure and chemical composition of the char material, providing a theoretical basis for the application of compression wood in carbonization. The carbonization was carried out under the nitrogen protection using a high-temperature tube furnace with four temperature settings of 220, 375, 600 and 900 ℃. The carbon yields of the two types of wood were calculated, and the changes of cell wall structure, chemical functional groups, and crystal structure under different charring temperatures were investigated using the scanning electron microscope, infrared spectroscopy, and X-ray diffraction. The carbon yield of the compression wood was higher than that of the opposite wood, and the carbonation yield decreased with the increase of carbonization temperature. The cell shrinkage and local rupture were observed in the compression wood at 375 ℃, while the opposite wood showed a smoother section of the char material. The cell wall rupture was severe at 900 ℃ in the compression wood, and granular material resembling microcrystals appeared on the cell walls, while the cell shrinkage and cell gap increased in the opposite wood, and the cell structure was still maintained. The infrared spectra showed that the thermal degradation of hemicellulose and cellulose in both types of wood started before reaching 375 ℃, and the lignin skeleton structure changed. As the carbonization temperature increased, the chemical substances and internal chemical bonding of the sample transformed progressively, such as the ether bond within the carbon material broke, the phenol, alcohol structures and marginal C—H regenerated, the lignin benzene ring skeleton degraded and reconfigured, with a tendency towards graphitization. The X-ray diffraction analysis showed that the crystal structure in the wood tissue was disrupted between 220 and 375 ℃, and a new crystal configuration appeared

关 键 词：樟子松 应压木 碳化 细胞壁结构 化学成分 

分 类 号：S781.29[农业科学—木材科学与技术]