FT-Raman spectra of cellulose and lignocellulose materials : “self-absorption” phenomenon and its implications for quantitative work

Abstract

The phenomenon of “self-absorption” was found to exist in the FT-Raman spectra of cellulose and thermomechanical pulp (TMP), but not in the spectrum of milled wood lignin. For cellulose and TMP, the effect was responsible for reducing the intensity of the Raman bands in the C-H stretch region. Several factors including sampling position, sample thickness, and moisture content of the sample affected the band suppression due to self-absorption. The intensity reduction, detected only in the C-H stretch region, was largely due to the fact that the aliphatic- and water- hydroxyl groups have nonfundamental vibration transitions in the near-IR frequency range that are coincident with the C-H Raman frequency shifts in FT-Raman. In light of these findings, ways are discussed to minimize or avoid the impact of self-absorption in quantitative work.

Citation

Agarwal, Umesh; Kawai, Nancy. 2003. FT-Raman spectra of cellulose and lignocellulose materials : “self-absorption” phenomenon and its implications for quantitative work. 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 127-130