Synchrotron X-ray structures of cellulose I and regenerated cellulose II at ambient temperature and 100 K
Authors: Langan, Paul; Sukumar, Narayanasami; Nishiyama, Yoshiharu; Chanzy, Henri
Source: Cellulose, Volume 12, Number 6, December 2005 , pp. 551-562(12)
Abstract:Synchrotron X-ray data have been collected to 1.4 Å resolution at the NE-CAT beam-line at the Advanced Photon Source from fibers of cellulose I and regenerated cellulose II (Fortisan) at ambient temperature and at 100 K in order to understand the effects of low temperature on cellulose more thoroughly. Crystal structures have been determined at each temperature. The unit cell of regenerated cellulose II contracted, with decreasing temperature, by 0.25%, 0.22% and 0.1% along the a, b, and c axes, respectively, whereas that of cellulose I contracted only in the direction of the a axis, by 0.9%. The value of 4.6×10−5 K−1 for the thermal expansion coefficient of cellulose I in the a axis direction can be explained by simple harmonic molecular oscillations and the lack of hydrogen-bonding in this direction. The molecular conformations of each allomorph are essential unchanged by cooling to 100 K. The room temperature crystal structure of regenerated cellulose II is essentially identical to the crystal structure of mercerized cellulose II.
Document Type: Research Article
Affiliations: Email: firstname.lastname@example.org
Publication date: December 2005