机构地区:[1]Key Laboratory of Science and Technology of Eco-textile,Ministry of Education,College of Chemistry and Chemical Engineering,Donghua University [2]State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,College of Materials Science and Engineering,Donghua University
出 处:《Journal of Donghua University(English Edition)》2007年第6期707-712,共6页东华大学学报(英文版)
基 金:Shanghai Nano Special Project(No.0452nm079)
摘 要:It has been reported that natural cellulose (cellulose I) can not be oxidized by TEMPO - NaOCI - NaBr system, one of TEMPO-mediated selective oxidant systems, but regenerated cellulose (cellulose Ⅱ ) can be completely selectively oxidized. In the present work, natural cellulose pulp was treated with NaOH solution, which concentration is lower than 20 wt%. The alkaline celluloses obtained were oxidized by TEMPO - NaOCI - NaBr system and the factors which influence the selective oxidation reaction rate have been investigated. The structure of the oxidized products has been characterized by Fourier transform-infrared (FTIR), nuclear magenatic resonace (NMR) and wide angle X-ray diffraction (WAXD) methods, and their adsorption properties for Cu^2+ and Cd^2+ in aqueous solutions have been preliminarily examined. The results show that after the alkaline treatment, the primary hydroxyl at C6 position of natural cellulose can be selectively oxidized to carboxyl group in the reaction medium at pH 10.8, the oxidation rate becomes greater with the NaOH concentration and alkaline treatment time increasing. The alkaline treatment has a great effect on the crystal structure of natural cellulose, but the crystal structure of alkaline cellulose keeps almost unchanged after oxidation. The adsorption capacity is enhanced by introducing carboxyl groups into the cellulose macromolecular chains.It has been reported that natural cellulose(cellulose I)can not be oxidized by TEMPO-NaOCl-NaBr system,one of TEMPO-mediated selective oxidant systems,but regenerated cellulose(cellulose Ⅱ)can be completely selectively oxidized.In the present work,natural cellulose pulp was treated with NaOH solution,which concentration is lower than 20 wt%.The alkaline celluloses obtained were oxidized by TEMPO-NaOCl-NaBr system and the factors which influence the selective oxidation reaction rate have been investigated.The structure of the oxidized products has been characterized by Fourier transform-infrared(FTIR),nuclear magenatic resonace(NMR)and wide angle X-ray diffraction(WAXD)methods,and their adsorption properties for Cu2+and Cd2+ in aqueous solutions have been preliminarily examined.The results show that after the alkaline treatment,the primary hydroxyl at C6 position of natural cellulose can be selectively oxidized to carboxyl group in the reaction medium at pH 10.8,the oxidation rate becomes greater with the NaOH concentration and alkaline treatment time increasing.The alkaline treatment has a great effect on the crystal structure of natural cellulose,but the crystal structure of alkaline cellulose keeps almost unchanged after oxidation.The adsorption capacity is enhanced by introducing carboxyl groups into the cellulose macromolecular chains.
关 键 词:natural cellulose pulp alkaline treatment TEMPO-mediated oxidations structure
分 类 号:TS74[轻工技术与工程—制浆造纸工程]
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