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为了系统探究速生材高得率浆发色系统在漂白过程中的变化,本实验采用差示紫外-可见光谱(DRUV)分析桉木CTMP浆在过氧化氢(H2O2)漂白、硼氢化钠(NaBH4)漂白和连二亚硫酸钠(Na2S2O4)漂白过程中的发色系统变化。结果表明,Na2S2O4漂白主要作用于发色基团的醌类结构,NaBH4可将不饱和双键还原为羟基,H2O2漂白效率较高,可作用于共轭羰基、碳碳双键和醌类结构。此外,在对桉木CTMP浆H2O2漂白的最佳条件进行探索时发现,增加H2O2用量可明显提高纸浆白度值和明度指数L*,当NaOH/H2O2的比值为0.9时,纸浆漂白效果最佳。
In order to systematically investigate the changes of fast-color high-yielding hair color system during bleaching, differential scanning UV spectroscopy (DRUV) was used to analyze the bleaching of hydrogen peroxide (H2O2), sodium borohydride (NaBH4 ) Bleaching and sodium dithionite (Na2S2O4) bleaching process changes in the color system. The results showed that Na2S2O4 bleaching mainly acted on the quinone structure of the chromophore. NaBH4 could reduce the unsaturated double bond to hydroxyl group. The bleaching efficiency of H2O2 was higher and could be used to the conjugated carbonyl, carbon-carbon double bond and quinone structures. In addition, exploring the optimum conditions for the bleaching of Eucalyptus CTMP pulp H2O2, it was found that increasing the dosage of H2O2 could significantly improve the pulp whiteness and lightness index L *. When the NaOH / H2O2 ratio was 0.9, the pulp bleaching effect was the best .