木纤维表面醛基化改性及自胶合性能评价  

Modification of Wood Fiber Surface by Aldehyde Groups and Property Evaluation of Self-Bonding Fiberboards

作　　者：张轶媛 陈媛[1] 李改云[1] 吴义强[2] Zhang Yiyuan;Chen Yuan;Li Gaiyun;Wu Yiqiang(Research Institute of Wood Industry,Chinese Academy of Forestry,Beijing 100091;College of Materials Science and Engineering,Central South University of Forestry and Technology,Changsha 410082)

机构地区：[1]中国林业科学研究院木材工业研究所,北京100091 [2]中南林业科技大学材料科学与工程学院,长沙410082

出　　处：《林业科学》2024年第8期174-183,共10页Scientia Silvae Sinicae

基　　金：国家自然基金重大项目(31890771);国家重点研发项目(2023YFD2200503)。

摘　　要：【目的】以杨木纤维为材料,通过氧化改性增强纤维表面反应活性位点,建立纤维表面羟基、醛基多位点网络结构,制备高强度、低吸水厚度膨胀率无胶纤维板,实现全生物质低碳、可循环生产利用。【方法】采用高碘酸钠氧化改性木纤维表面基团,建立高反应活性醛基网络位点,通过醛基含量测定、扫描电镜(SEM)、傅里叶红外光谱(FTIR)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、热重分析仪(TG)、差示扫描量热仪(DSC)分析反应前后及不同醛基含量木纤维的微观结构和化学成分变化规律;利用化学键交联在低温热压条件下制备自胶合纤维板,探究醛基化木纤维制备无胶纤维板的力学性能和吸水厚度膨胀率。【结果】通过反应时间、温度、氧化剂浓度等条件控制,可实现木纤维醛基化定量改性;与原纤维对比,醛基化纤维表面粗糙度增大、纤维尺寸变短、纤维素聚合度下降,纤维素-半纤维素-木质素包覆结构疏松,木纤维表面产生大量孔隙;纤维素结晶区随反应强度增加逐渐被破坏,醛基化木纤维的热稳定性随醛基含量升高逐渐降低,有利于无胶纤维板的低温热压成型。醛基化木纤维在热压过程中通过化学键交联可实现自胶合,热压温度和醛基化木纤维醛基含量对无胶纤维板的性能具有显著影响,通过优化原料和工艺条件制备的无胶纤维板具有优异的力学性能和耐水性。【结论】通过控制反应条件可得到不同醛基含量的醛基化木纤维,实现对木纤维表面醛基的可控改性;自胶合过程中温度过低(50℃)易导致醛基化木纤维耐水性差,温度过高(125℃)易造成醛基化木纤维降解,引起鼓泡、膨胀、碳化,降低纤维板力学性能。当高碘酸钠浓度0.07 mol·L^(−1)、反应温度30℃和反应时间6 h时,木纤维醛基含量为1.86 mmol·g^(−1);在热压温度100℃、压力20 MPa和热压5 min时,制备的自胶合醛【Objective】Taking poplar wood fiber as material,enhance the reactive sites on the fiber surface by oxidative modification,establish the multi-site network structure of hydroxyl and aldehyde groups on the fiber surface,and prepare highstrength,low-absorbent thickness expansion rate of self-bonding fiberboard,so as to achieve the whole biomass low-carbon and recyclable production and utilization.【Method】The surface groups of wood fiber were oxidatively modified by sodium periodate to establish highly reactive aldehyde group network sites,and the aldehyde group content was determined by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetric analyze(TG),and differential scanning calorimetry(DSC),which analyzed the microstructure and chemical structure of wood fiber before and after the reaction,as well as the content of different aldehyde groups.Using chemical bond cross-linking in low temperature hot pressing conditions to prepare self-glued fiberboard,to explore the mechanical properties of dialdehyde wood fibers to prepare self-bonding fiberboards and absorbent thickness expansion rate.【Result】The quantitative modification of dialdehyde wood fibers can be realized by controlling the conditions of reaction time,temperature,and concentration of oxidizing agent;comparing with the original fibers,the surface roughness of dialdehyde wood fibers increased,the fiber size became shorter,and the degree of cellulose polymerization decreased,the cellulose-hemicelluloselignin encapsulation structure was loosened,and a large number of pores were produced on the surface of wood fibers.The cellulose crystallization zone was gradually destroyed with the increase of reaction strength,and the thermal stability of dialdehyde wood fibers increased with the increase of reaction strength.The thermal stability of dialdehyde wood fibers gradually decreases with the increase of aldehyde content,which is conducive to the low-

关 键 词：醛基化木纤维 无胶胶合 力学性能 

分 类 号：S781.4[农业科学—木材科学与技术]