Research On Ramie Hemicellulose Component

Ramie was known as “China grass”.Ramie, with high strength and excellent moisture absorption, is one kind of textile raw materials. Non-cellulosic gummy metarials needs to be removed from raw ramie in order to get fibers. Gum in ramie contained wax, water soluble, pectin, hemicellulose and lignin. The degumming process was selected according to gum properties.Pectin and hemicellulose were polysaccharide in ramie gums.Hemicellulose, which takes up about half amount of total gummy components, was the important component in ramie. Hemicellulose is a mixture of various kinds of polysaccharide. A study of ramie hemicellulose composition and the effect of different kinds of polysaccharide on fiber properties can provide useful message in reasonably removing the gummy substances.In this research,the influence of different kinds of gums on ramie was studied. The chemical compositions of hemicellulose in ramie fibers were thoroughly investigated. The effect of polysaccharide on fiber properties was systematically explored. The effect of chemical treatment on polysaccharide in ramie was researched. Ammonium oxalate-sodium hydroxide degumming craft was explored. This research can provides suggestion for formulated a degum craft with the low cost and the low pollution.The effects of different kinds of gum on fiber properties were researched.The effects of wax and water soluble on fiber separation were not significant. The effects of pectin and hemicellulose on fiber separation were significant. The effects of pectin and hemicellulose on fiber fineness were also significant. The break elongation and the breaking tenacity increase after hemicellulose removed from ramie.The chemical compositions of ramie hemicellulose were researched. An alkaline method was used to extract the hemicellulose from ramie. The best extract process was: Extraction was repeated three times with solution of 24%(w/w)KOH, then another repeated three times with a mixed solution of 17.5%(w/w)Na OH and 4%(w/w)H3BO3 at 25℃ for 48 h. The total yield of hemicellulose was 14.43%.GC analysis indicated that there are no hemicellulose in ramie residual after extraction.GC, FTIR and paralysis analysis were used to study composition and structure of ramie hemicellulose. GC analysis indicated that ramie hemicellulose mainly contained the components of galactose, mannose, glucose, xylose, arabinose and rhamnose. Among them, galactose, mannose and glucose were the major sugar monomers in ramie hemicellulose. FTIR analysis indicated the sugar units in ramie hemicellulose were connected by β-glycoside bond. The paralysis’ products of ramie hemicellulose mainly consist of the carbon dioxide, the small molecular organic substance and pyranose. Xylan, glucomannan and galactoglucomannan was successfully separated and extracted from ramie with high alkali concentration methods. The components of galactoglucomannan, glucomannan and xylan, accounted for about 79.0% of total weight in ramie hemicellulose, were the major sugar monomers in ramie hemicellulose. FTIR analysis indicated the xylan in ramie was arabinoglucuronoxylan.The influence of hemicellulose content on fiber performance indicated that with the increase of hemicellulose content, fiber linear density decrease. The break elongation and the breaking tenacity increases gradually along with the hemicellulose content decrease. Considered fiber fineness, break elongation, break tenacity and degum cost, the hemicellulose content in ramie lower than 1.22% is suitable. The effects of polysaccharide(galactoglucomannan, glucomannan and xylan) content on ramie fiber properties were systematically discussed. With the increase of galactoglucomannan, glucomannan and xylan contents, the fiber linear density and unseparated fiber percentage showed increase trend, while the fiber tenacity exhibited decrease trend under the same condition. Additionally, it was demonstrated that the contents of these three components were insignificant on friction coefficient, breaking elongation, modulus and resilience of ramie fibers.The effect of chemical treatment on polysaccharide in ramie gum was discussed. The research indicates that the solubility of pectin in sulfuric acid, sodium hydroxide and hydrogen peroxide solutions is higher then that of hemicellulose different. The solubility of galactoglucomannan, glucomannan and xylan is different in sodium hydroxide solutions. Galactoglucomannan was more easily soluble than glucomannan in 10g/L sodium hydroxide solution.The method of gradually remove different kinds of ramie gum was applied to indicate the influence of other ingredients on the sodium hydroxide removing polysaccharide in ramie. The water-soluble substance and pectin have the hindrance function on the sodium hydroxide removing hemicellulose. Water soluble and wax has the hindrance function on the sodium hydroxide removing pectin. These results can provide new degumming method that we can try to remove most of water soluble and pectin first, and then remove the hemicellulose by sodium hydroxide solutions with low concentration. The ramie degumming process of fist treated by ammonium oxalate solution then treated by sodium hydroxide solution was explored in this paper. Optimized craft of the process obtain by the single factor and the orthogonal experiment were: First step ammonium oxalate treatment: ammonium oxalate concentration 8g/L, treatment time 1.5h, bath ratio 1:10, temperature 100℃, second step sodium hydroxide treatment: bath ratio 1:10, temperature 100℃, sodium hydroxide concentration 10g/L and process time 3h.After degummed by this process, the pectin and hemicellulose in ramie and the fiber property was close to the fiber degummed by traditional chemical methods. Compared to traditional chemical methods, optimized craft of ammonium oxalate process reduce the alkaline dosage and treatment time.