Composition of ramie hemicelluloses and effect of polysaccharides on fiber properties

Ramie, which is one of the most important natural fibers, possesses distinctive characteristics and excellent properties. In this study, the chemical compositions of hemicelluloses in ramie fibers were thoroughly investigated. The effect of NaOH treatment on polysaccharides in hemicelluloses and the effect of polysaccharides on fiber properties were systematically explored. It was found that the components of galactoglucomannan, glucomannan, and xylan accounted for about 79.0% of total weight in ramie hemicelluloses. Galactoglucomannan was more easily soluble than glucomannan in 1% (w/w) NaOH solution. Xylan possessed the lowest solubility in the same concentration of NaOH solution compared to the other two. Furthermore, with an increase of galactoglucomannan, glucomannan, and xylan contents, the fiber linear density and unseparated fiber percentage showed an increasing trend, while the fiber tenacity exhibited a decreasing trend under the same conditions. In addition, it was demonstrated that the contents of these three components have an insignificant effect on friction coefficient, breaking elongation, modulus, and resilience of ramie fibers. This study could provide useful information in understanding the nature of hemicelluloses and polysaccharides within natural fibers, as well as theoretically guiding the degumming process of ramie fibers.