溶剂抽提物对尾巨桉热变色的影响及光谱分析

为探讨溶剂抽提物对尾巨桉热变色的影响,在过热蒸气条件下对抽提物进行热处理,之后采用冷水、热水、乙醇、甲醇、丙酮、正己烷等6种溶剂对热处理前后的尾巨桉木粉进行抽提,对热处理前后经过抽提的木粉进行色度指数的测定和红外光谱分析,并对抽提物进行紫外光谱分析。结果表明:1极性溶剂抽提物对尾巨桉颜色及其热处理后颜色变化影响较大,其中热水抽提物对颜色的影响最显著;2抽提物热处理后共轭结构增加,共轭体系能量降低,吸收带延伸至可见光范围,是木材受热后颜色加深的重要原因;3热处理后,尾巨桉木粉ΔL*为负值,即颜色变深,木材颜色均匀美观,可提高利用价值。

Effect of Extractives on Color Changes of Eucalyptus urophyll a ×Eucalyptus grandis and Its SpectrumA nalysis

Overheating steam treatment can darken the color of Eucalyptus urophylla×Eucalyptus grandis wood and make it look like precious wood, which can improve its utility value.For studying the effect of overheating steam treatment on discolora-tion of Eucalyptus urophylla ×Eucalyptus grandis wood, we extracted the wood powder before and after heating treatment with cold water, hot water, alcohol, methyl alcohol, and acetone and n-hexane, and measured the color parameters of the samples before and after extracted.We used ultraviolet absorption spectrum and the FTIR spectra to evaluate chemical changes of extractives and wood powder.Polar solvents extract was more effective on color and color changes of E.grandis wood powder after heat treatment.Hot water extraction had the most important influence on wood color.The important rea-sons of color deepen after heat treatment were:after heat treatment, the conjugated structures of extractives increased, and the energy of conjugated system decreased, and the absorption band extended to the visible light range.After heat treat-ment,ΔL* value of E.urpoh ylla×E.grandis wood powder was negative, which meant the color was deepen, and the color of wood was uniform and beautiful with high utility value.