圆盘豆热处理材颜色变化及其变化机理

试验采用过热蒸汽作为传热介质和保护气体,对圆盘豆木材进行热处理,热处理温度为160℃、180℃、200℃、220℃,热处理时间为2h、4h、6h、8h,并采用紫外光谱和气-质联用对圆盘豆木粉抽提物进行分析。结果表明,热处理后圆盘豆木材颜色发生明显变化。随着热处理温度升高,木材明度L*下降,红绿色品指数a*变化不明显,黄蓝色品指数b*下降,色差△E*增大,木材表面颜色加深,其主要原因是木素及木材抽提物发生了氧化、还原反应。

Color Change and Relevant Mechanism of Okan Wood after Thermal Treatment

With superheated steam as a heat transfer medium and a protective gas,the termal treatment of okan wood is conducted at different temperatures of 160℃,180℃,200℃,and 220 ℃ for 2h,4h,6h andd 8h respectively,with UV spectroscopy and gas chromatography-mass spectrometry used for the analysis of okan wood powder extract.The results show that the color of okan wood changes obviously after thermal treatment.With the increase in heat treatment temperature,the wood brightness parameter L* decreases sharply,red and green index a* doesn’t change noticeably,yellow and blue index b* declines and color difference △E* increase evidently with the darkening of wood surface color.These are mainly caused by the oxidation and reduction reactions of lignin and wood extract.