【作者】 刘毅；

【导师】 高建民； 郭洪武；

【作者基本信息】 北京林业大学 ， 木材科学与技术， 2015， 博士

【摘要】 木材染色单板的光变色机制及防护技术研究是木材调色领域的重要科学问题。本文以木材染色单板及其化学组分为研究对象,探讨了不同光源辐射下染色单板的光变色过程及响应关系,研究了染色单板发色体系中染料、综纤维素、木素和抽提物的结构变化历程及光氧化机制,同时开展了染色基质乙酰化处理、超声波辅助木材染色、水性透明涂料涂饰等防护技术的研究。主要结论如下：（1）染色单板的光变色度随辐射时间的延长而增加,辐射初期变色速率最快。光辐射过程中染色单板发生了淡色效应,染色单板对可见光的选择性吸收能力减弱。光辐射后染色单板K/S曲线呈下降趋势,光谱反射率曲线向长波方向发展,染色单板发生黄化。利用光谱反射曲线可快速直观地评估染色单板的耐光性。（2）染料和木材化学结构在对不同波长光的选择性吸收上起着复杂的协同作用。染色单板的光变色程度和速率与染料、木素和光辐射光的能量和波长密切相关。（3）染色单板在氙光、紫外光辐射下的光变色度与自然光辐射之间存在关系式：△E*x=1.095△E*N+3.005,AE*u=0.651△E*N+1.458。加速因子的实质是光辐射度的比率。（4）紫外光辐射过程中,染料发生了光氧化光降解反应。染色综纤维素的光氧化降解路径：纤维素葡萄糖基环的苷-OH（C₁）、伯-OH（C₆）、仲-OH（C₂、C₃）→醛-CHO或酮-C=O→羧酸-COOH。紫外光辐射使得纤维表面某些薄弱组织结构发生了严重劣化,纤维表面光刻蚀特征明显。（5）染色木素分子结构中的不饱和官能团发生苯氧自由基反应,形成羰基或醌类化合物,木素通过循环发生苯氧-醌-氧化还原反应而逐步光氧化降解。染色单板的光变色度△E^*与木材木素的降解及羰基基团的生成之间成线性关系。木材中某些抽提物具有抗氧化功能,经过氧化氢预处理后,染色单板的耐光性下降。（6）超声波辅助处理提高了木材单板的渗透性,创造了新的流体通道和染料吸附位点,提升了木材单板的上染率,同时提升了其耐光性。乙酰化处理能有效提高染色木材的抗光降解能力和热稳定性。水性涂饰处理对木质材料表面光变色具有良好的抑制效果,主要在于其能显著抑制材料表面黄蓝色品指数b^*的增加。更多还原

【Abstract】 Photo-chromic mechanism and protection technology are the important scientific problems in the development of plantation wood color modulation. This paper studied the dyed wood veneer and its chemical constituents. The color changing process and response relation of dyed wood veneer under different light source radiation were discussed. The structure changes, light oxidation and degradation mechanism of dyes, ensemble cellulose, lignin, and extractives were investgated. The dyeing matrix acetylation, ultrasonic assisted wood dyeing, transparent water coated were also studied. The main results are as follows:(1) The color change degree increased with radiation time prolong, the discoloration rate was the fastest at early radiation. K/S curves of dyed wood veneer sufferd a downward trend after optical radiation, and the direction of long wave spectral reflectance curve developed. Spectral reflection curve can used to quickly visually assess the light fastness of dyed wood veneer.(2) Dyes and wood chemical structure plays a complex synergy on the selective absorption of different wavelengths of light. The color fastness rate of dyed wood veneer was closely related to dyes, lignin, the optical energy and wavelength of optical radiation.(3) The color change relation of dyed wood veneer under the xenon, ultraviolet and natural light radiation was △E*x=1.095AE*N+3.005, △E*u=0.651 △E*N+1-458. The essence of the acceleration factor is the ratio of optical radiation degree.(4) The dyes suffered photooxidation photodegradation reaction. The light oxidation degradation path of cellulose as follow, cellulose glucose glycosides of base ring-OH (C1), OH (C6), para-OH (C2 and C3), aldehyde-CHO or ketone-C=O, carboxylic acid-COOH. Ultraviolet radiation made some weak dyed veneer fiber surface became more serious degradation, the organizational structure and wood cell wall portion such as the pit membrane was destroyed.(5) The unsaturation structure of the lignin were degraded by of benzene oxygen free radical reaction, the formation of carbonyl or quinone compounds, lignin by recurring benzene oxygen - quinone - light oxidation degradation of REDOX reaction. A linear relationship between the photochromic degree △E* of deyed wood vener and the lignin degradation and the formation of carbonyl group was founded.(6) Ultrasonic auxiliary treatment improved the permeability of wood veneer, created new fluid channels and the dye adsorption sites, and improved the light fastens of deyed wood, which is a gtreat wood dyeing method. Acetylation treatment effectively improved the ability to resist photodegradation of dyed wood and thermal stability. Water-based paint processing light discoloration of woodiness material has good inhibition effect, mainly depends on it inhibited the yellow and blue index b* incressed更多还原