关键词:

黄麻纤维, 木质素, 漆酶, TEMPO, 氧化

Abstract: In this paper, jute fibers were catalytically oxidized by the laccase/TEMPO system, the lignin content in jute fibers before and after the treatment was determined through the Klason method, and the molecular weight and distribution, element content as well as the chemical structure of lignin extracted from jute fibers by the dioxane method were determined using gel permeation chromatography, organic elemental analysis and hydrogen nuclear magnetic resonance spectroscopy, respectively. The results showed that the lignin content in jute fibers decreased from 10.83% to 8.59% after the laccase/TEMPO treatment. The lignin remaining on jute fibers was also degraded, with the weight average molecular weight decreasing from 439,938 Da to 238,704 Da. For the lignin of laccase/TEMPO-treated jute fibers, its carbon content increased, oxygen content and OCH3 content decreased, and the number of alcohol hydroxyl groups decreased, while the number of phenolic hydroxyl groups decreased slightly. Besides, the connection type between structural units of lignin also changed, with the proportion of β-β, β-1and β-O-4 structure decreasing and the proportion of β-5 structure increasing. The results indicated that the laccase/TEMPO catalyzed oxidation reaction of jute fiber lignin was accompanied by some demethylation, and β-β, β-O-4 and β-1 bonds were mainly broken during lignin degradation and then β-5 links were formed.

Key words:

jute fiber, lignin, laccase, TEMPO, oxidation