乙醇抽提物对刺槐木材热诱导变色过程的影响

Effect of Ethanol Extractive on Heat-induced Discoloration of Robinia Pseudoacacia

为了提高刺槐木材的利用率,通过热处理改性获得理想的木材颜色,分析了刺槐木材中乙醇抽提物的结构及其在热处理过程中对木材颜色的影响。研究表明,刺槐木材乙醇抽提物中C=C、C-O-C、-OH和苯环等基团的合成可导致木材红绿轴色品指数a*升高,黄蓝轴色品指数b*降低,但对于明度值L*几乎没有影响;同时,热处理后的木材中羟基被氧化成羰基,不饱和有机酸酯类结构生成。抽提后再加热处理的木材避免了羟基氧化反应和不饱和有机酸酯的生产反应,但苯环取代基在抽提后热处理的刺槐木材中减少了,所以变色程度下降。

To improve the utilization rate of Robinia pseudoacacia wood and obtain the ideal wood color through heat treatment modification,the structure of ethanol extractive from Robinia pseudoacacia and its effect on wood color during heat treatment were analyzed.In this paper,the ethanol extractive and the sample of Robinia pseudoacacia treated with saturated steam in advance were analyzed.The infrared spectrum analysis showed that the ethanol extractive contains C=C,C-O-C,-OH,benzene ring and other groups.The synthesis and decomposition of these groups lead to an increase in the wood red-green product index a*and a decrease in the yellow-blue product index b*,but it had little effect on the lightness value L*;meanwhile,the aromatic ring structure in the wood after heat treatment decrease,hydroxyl group was oxidized to carbonyl group,unsaturated organic acid ester structure was generated.The heat-treated specimens after extractiveion avoided the hydroxyl oxidation reaction and unsaturated organic acid ester production reaction,but the benzene ring substituents are reduced in the Robinia pseudoacacia heat-treated after extractive,so the degree of discoloration decreased.