NIR FT Raman spectroscopy - a rapid analytical tool for detecting the transformation of cellulose polymorphs

This is a report of the combined use of NIR FT Raman spectroscopy and X-ray diffraction measurements (WAXS) to investigate the polymorphic transformation of cellulose I into cellulose II. For this reason samples of cellulose I were swelled in different concentrations of NaOH and dissolved in different molten inorganic salts hydrates (LiCl . 2ZnCl(2). 6H(2)O, LiClO4. 3H(2)O, LiSCN .2,5H(2)O and ZnCl2. 4H(2)O). NIR FT Raman spectra of the alkali treated samples were recorded. They characterize the pure modifications cellulose I and II as well as mixtures of the two polymorphic phases. The results of the Raman measurements were confirmed by X-ray scattering. The paper demonstrates that FT Raman vibrational spectroscopy is a powerful, rapid analytical method which may be used to follow the polymorphic transformation of cellulose I into cellulose II.