Combined Infrared and Electron Diffraction Study of the Polymorphism of Native Celluloses

Abstract

In this study, 10 cellulose samples of various origins were subjected to heat annealing in 0.1 N NaOH at 260 °C. The initial and annealed samples were analyzed by electron diffraction experiments. It was confirmed that the initial samples contained various proportions of la (triclinic) and 10 (monoclinic) phases. They could be classified into two families: a family I where the amount of the phase lα was either small or below detection and a family II where this phase was the major component. The annealing treatment revealed that the lα phase was metastable as it could be converted totally to the stable Iβ phase. The conversion lα →1β was also followed by Fourier transform infrared (FT-IR) spectroscopy. Absorption bands near 3240 and 750 cm−1 were assigned to the lα phase whereas bands near 3270 and 710 cm−1 corresponded to the Iβ phase. © 1991, American Chemical Society. All rights reserved.