Department of Textile Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia.
Carbohydr Polym. 2013 Oct 15;98(1):444-50. doi: 10.1016/j.carbpol.2013.06.033. Epub 2013 Jun 26.
The effects of TEMPO-mediated oxidation, performed with NaClO, a catalytic amount of NaBr, and 2,2',6,6'-tetramethylpiperidine-1-oxy radical (TEMPO), were studied on lyocell fibers by means of GPC using multiple detection and group-selective fluorescence labeling according to the CCOA and FDAM methodology. The applied method determines functional group content as a sum parameter, as well as functional group profiles in relation to the molecular weight of the cellulose fibers. Both the CHO and COOH profiles, as well as molecular weight alterations, were analyzed. A significant decrease in the average molecular weight was obtained during the first hour of TEMPO-mediated oxidation, but prolonged oxidation time resulted in no strong additional chain scission. Significant amounts of COOH groups were introduced in the high molecular weight fractions by the oxidation with higher concentrations of NaClO (2.42-9.67 mmol NaClO/g fiber) after modification times of 1h or longer.
采用 GPC 多重检测和根据 CCOA 和 FDAM 方法进行的选择性荧光标记，研究了 TEMPO 介导的氧化（使用 NaClO、催化量的 NaBr 和 2,2',6,6'-四甲基哌啶-1-氧基自由基 (TEMPO)）对粘胶纤维的影响。所应用的方法将官能团含量作为总和参数确定，以及与纤维素纤维分子量有关的官能团分布。分析了 CHO 和 COOH 分布以及分子量变化。在 TEMPO 介导的氧化的最初一小时内，平均分子量显著降低，但延长氧化时间不会导致进一步的强烈链断裂。在用更高浓度的 NaClO（2.42-9.67 mmol NaClO/g 纤维）进行氧化后，在 1 小时或更长的改性时间后，在高分子量部分中引入了大量的 COOH 基团。
