路易斯酸预处理对木材热降解特性的影响  

Effects of Lewis acid pretreatment on thermal degradation characteristics of wood

作　　者：王旭洁 姚三川 雒翠梅 母军[1] 漆楚生 Wang Xujie;Yao Sanchuan;Luo Cuimei;Mu Jun;Qi Chusheng(Key Laboratory of Wood Material Science and Application,Beijing Key Laboratory of Wood Science and Engineering,School of Materials Science and Technology,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学木质材料科学与应用教育部重点实验室,木材科学与工程北京市重点实验室,北京林业大学材料科学与技术学院,北京100083

出　　处：《北京林业大学学报》2024年第11期133-140,共8页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(31971589)。

摘　　要：【目的】引入外源酸可解决热处理温度高、时间长的问题,提高热效率。本研究旨在明确外源酸对木材组分的影响以及不同木材的热降解特性。【方法】以两种针叶材(落叶松、杉木)和两种阔叶材(桉木、杨木)为研究对象,以路易斯酸中的AlCl_(3)为外源酸,采用傅里叶变换红外光谱(FTIR)、热重分析(TGA)和Flynm-Wall-Ozawa法研究了不同浓度AlCl_(3)溶液(0、0.1、0.3 mol/L)处理后木材的热降解特性。【结果】AlCl_(3)处理可对木材化学结构产生显著影响:半纤维素的特征峰显著降低并发生红移,木质素特征峰的峰值增加,总结晶度指数减少,OH/CH_(2)比值下降,以及氢键强度增加。其中,0.3 mol/L AlCl_(3)溶液处理试材的总结晶度指数减少了29.17%~52.67%,OH/CH_(2)比值降低了23.18%~51.01%,氢键强度增加了2.86%~13.27%,纤维横向有序度减少低于8%。在热解过程中,AlCl_(3)处理后木材降解温度均降低,降解速率增大,活化能降低。0.3 mol/L处理浓度下,木材起始降解温度均降低至110℃以下,且针叶材出现明显肩峰,在快速热降解阶段针叶材的活化能比阔叶材显著降低。【结论】引入AlCl_(3)能显著降低木材的热降解温度,从而有效提升木材热改性效率,且其对针叶材的催化作用相较于阔叶材更为显著。本研究可为路易斯酸在木材低温热处理领域的应用提供理论支持。[Objective]The introduction of exogenous acid can solve the problem of high temperature and long time during heat treatment and improve thermal efficiency.It is necessary to clarify how exogenous acid affects wood components and thermal degradation characteristics of different woods.[Method]Two types of softwood(larch,Chinese fir)and two types of hardwood(eucalyptus,poplar)were studied,and AlCl_(3) in Lewis acid was taken as exogenous acid.The thermal degradation characteristics of wood treated with different concentrations of AlCl_(3) solution(0,0.1,0.3 mol/L)were studied by Fourier transform infrared spectroscopy,thermogravimetric analysis and Flynm-Wall-Ozawa method.[Result]AlCl_(3) treatment had significant effects on chemical structure of wood,which showed that the characteristic peak of hemicelluloses decreased significantly,the redshift occurred,the intensity of lignin characteristic peak increased,the total crystallinity index(TCI)decreased,the OH/CH_(2) ratio decreased,and the hydrogen bond strength(HBI)increased.After 0.3 mol/L AlCl_(3) solution treatment,TCI of the samples decreased by 29.17%-52.67%,OH/CH_(2) ratio decreased by 23.18%-51.01%,HBI value increased by 2.86%-13.27%,and the lateral order intensity of fiber was reduced by less than 8%.During the pyrolysis process,the degradation temperature of samples decreased,the degradation rate increased,and the activation energy decreased after AlCl_(3) treatment.When the treatment concentration was 0.3 mol/L,the initial degradation temperature of wood was reduced to below 110℃,a obvious shoulder peak appeared in softwood,and the activation energy of softwood was significantly lower than that of hardwood at the rapid thermal degradation stage.[Conclusion]The introduction of AlCl_(3) can significantly reduce the thermal degradation temperature of wood,thereby effectively improve the thermal modification efficiency of wood.Its catalytic effect on softwood wood is more significant than that on hardwood.The research can provide theoretical support for the

关 键 词：降解 热处理 木材 热动力学 热重分析 催化 路易斯酸 针叶材 阔叶材 

分 类 号：S781.46[农业科学—木材科学与技术]