用ESR研究纸张中的自由基

ESR Studies of Free Radicals in Paper

书刊纸和新闻纸经紫外线辐照，具有增强的ＥＳＲ信号，其谱线均为无超精细结构的单峰，属高斯型，线宽约为１０×ｌ０－４特斯拉，ｇ值为２．００５。经比较分析，增强的ＥＳＲ信号，主要来自纸张中的木素，其受紫外线辐照，不断产生新的自由基。此方法可以迅速检测纸张所含木素，并可预测纸经长时期日光光化作用的效果。

Under UV irradiation, printing grades for books, periodicals and newspaper gave off strengthening ESR signals. providing non-hyperfine structural single peak spectra typically of Gauss nature. Typical spectrum width is found to be around 10 10-4 tesla, and the g value is 2. 005, Comparative analysis disclosed that such strengthening ESR signals come mainly from the lignin in the paper. Free radicals are presumably being continuously emitted form lignin. The method of UV irradiation may be employed as a rapid approach for lignin content determinations in papers and serves as a means for the prediction of paper permanency under sunlight photochemical action.