变色泡桐木材脱色后组分及热稳定性  

Components and thermal stability of discolored Paulownia wood after decolorization

作　　者：许雅雅 常德龙 楚杰[3] 胡伟华 黄文豪 张云岭 陈妮[3] 谢非凡 XU Yaya;CHANG Delong;CHU Jie;HU Weihua;HUANG Wenhao;ZHANG Yunling;CHEN Ni;XIE Feifan(Key Laboratory of Non-timber Forest Germplasm Enhancement&Utilization,China Paulownia Research Center,National Forestry and Grassland Administration,Zhengzhou 450003,Henan,China;Nanjing Forestry University,Nanjing 210037,Jiangsu,China;Northwest Agriculture and Forestry University,Yangling 712100,Shaanxi,China)

机构地区：[1]国家林业和草原局泡桐研究开发中心,经济林种质创新与利用国家林业和草原局重点实验室,河南郑州450003 [2]南京林业大学,江苏南京210037 [3]西北农林科技大学,陕西杨凌712100

出　　处：《中南林业科技大学学报》2022年第1期167-174,共8页Journal of Central South University of Forestry & Technology

基　　金：中国林业科学研究院基本科研业务费专项(CAFYBB2017ZX003-13);国家林业和草原局林业科学技术推广项目([2019]-38,2020133140);陕西省农业科技攻关项目(2020NY-120)。

摘　　要：【目的】探究脱色伴随的变色泡桐木材材色、组分结构和热稳定性变化特点,旨在为泡桐脱色工艺方法提供科学依据和理论支撑。【方法】以兰考泡桐变色木材为试验材料,通过构建脱色处理体系(过氧化氢H_(2)O_(2)、次氯酸钠NaClO、亚氯酸钠NaClO_(2)为脱色剂,30、50、70℃为温度条件),分析脱色前后样品的色差指标和化学组分变化,采用热重分析仪分析脱色前后样品的热稳定性。【结果】H_(2)O_(2)脱色后色差值达到了23.84,亮度和白度均有很大程度的提高,H_(2)O_(2)脱色后纤维素含量达到了63.62%,增加了15.72%,抽提物由3.18%减少至0.12%;NaClO_(2)脱色后,木质素含量降低了4.78%;NaClO脱色后纤维素含量为51.02%,仅增加了4.02%,木质素共减少了2.15%,抽提物含量为2.75%,仅减少了0.43%。温度变化条件下,亮度和色差均在70℃时达到最大。傅里叶红外光谱特征显示,在不同脱色条件下,纤维素的红外吸收特征峰呈现不同的变化趋势,脱色样品中半纤维素的特征吸收峰羰基的C=O伸缩振动峰明显减弱,证明脱色一定程度降解了半纤维素,NaClO_(2)脱色后木质素酚醚键C—O—C的伸缩振动峰减弱,进一步验证了木质素含量降低的结果。TG和DTG曲线显示脱色前后以及不同脱色条件获得的样品热解特性有差异,H_(2)O_(2)和NaClO脱色后热解起始温度高于未处理材,NaClO_(2)脱色后热解起始温度低于未处理材,50℃条件下脱色后样品的热解起始温度略高于30℃和70℃条件下。【结论】不同脱色剂脱色条件下,H_(2)O_(2)脱色效果最佳;温度变化条件下,NaClO_(2)在70℃时脱色效果最好;脱色后纤维素相对含量大幅增加,木质素和抽提物相对含量减少;傅里叶红外光谱验证了脱色材主成分的变化,从基团变化的角度揭示材色变化的机理;H_(2)O_(2)和NaClO脱色的样品热稳定性有所提升,NaClO_(2)脱色使得热稳定性略有下降。【Objective】The aim of the study was to explore the changes of color,component structure and thermal stability of discolored Paulownia wood due to decolorization,to provide a scientific basis and theoretical support for the Paulownia decolorization technology.【Method】Taking the discolored Paulownia elongata wood as the research objects,this study conducted decolorization treatment with hydrogen peroxide(H_(2)O_(2)),sodium hypochlorite(NaClO),and sodium chlorite(NaClO_(2))as the decolorizing agents,and the experiments were performed at 30℃,50℃,and 70℃.The variation of color difference indexes and chemical composition of the samples were analyzed before and after decolorization,while the thermostability of the samples was determined via the thermogravimetric analyzer.【Result】After the decolorization with H_(2)O_(2),the color difference reached 23.84,with brightness and whiteness being greatly improved.The cellulose content reached 63.62%with a relative increase of 15.72%,while the content of lignin was reduced by 10.68%and the content of extracts was reduced to 0.12%.After the decolorization with NaClO_(2),the lignin content was reduced by 4.87%.After the decolorization with NaClO,the cellulose content reached 51.02%,exhibiting a relative increase of 4.02%in comparison with the untreated samples,and the lignin content was reduced by 2.15%,while the content of extracts was reduced to 2.75%,showing a decrease of 0.43%.Under the condition of temperature variations,the brightness and color difference reached the maximum value at 70℃.The characteristics of Fourier infrared spectroscopy showed that under different decolorization conditions,the infrared absorption characteristic peaks of cellulose showed different changing trends.The C=O stretching vibration peak of the carbonyl group in hemicellulose in the decolorized sample was significantly weakened,proving that the hemicellulose was degraded to a certain extent due to decolorization.The stretching vibration peak of the phenol ether bond C-O-C in li

关 键 词：木材脱色 色差 化学组分 红外光谱分析 热重分析 

分 类 号：S781.42[农业科学—木材科学与技术]