Raman microprobe analysis of single ramie fiber during mercerization

Abstract

The Raman microprobe technique was applied to structural analysis of single ramie fibers during mercerization. Polarized laser beam was irradiated on a ramie fiber in 0-30 % NaOD/D2O with the electric vector at 0 or 90° to the fiber axis, and Raman spectra thus obtained were studied in relation to the concentration of NaOD in D2O. Conversion of -OH to -OD in ramie cellulose with NaOD/D2O proceeded with an increase in the concentration of NaOD, and almost all OH groups in ramie cellulose were converted to -OD by the treatment with NaOD/D2O of more than 15 %; almost all intra- and inter-molecular hydrogen bonds originally present in native ramie cellulose are cleaved by NaOH during mercerization. Polarized Raman spectra of ramie fibers showed that clear orientation of cellulose chains along the fiber axis was present in both original and mercerized ramie states. On the other hand, Raman spectra of ramie fibers swollen in 17.5- 0 % NaOD/D2O showed isotropic patterns, indicating that the orientation disappeared in the swollen Na-cellulose states.

Citation

Isogai, Akira; Agarwal, Umesh P.; Atalla, Rajai H. 2003. Raman microprobe analysis of single ramie fiber during mercerization. 12th ISWPC International Symposium on Wood and Pulping Chemistry : Madison, Wisconsin, June 9-12, 2003, proceedings. Volume III, Poster presentations. [Madison, WI : University of Wisconsin--Madison, Dept. of Forest Ecology and Management, 2003]: Pages 263-266