X-ray diffraction characterization of a distorted Debye–Scherrer film strip – the effect of deacetylation on cellulose triacetate and an improved structural model for cellulose II

A Debye–Scherrer film that had been stored for several years in an office environment file cabinet was observed to be shriveled and distorted in appearance. An investigation using X-ray diffraction was carried out to determine the cause of the physical change in the film strip. As expected, silver phases were detected, due to the photographic capture layer coated on the surface of all traditional X-ray films. An unexpected result was the presence of cellulose II, an indication that a chemical change had occurred in the original cellulose triacetate (CTA) polymer film base. Laboratory experiments used to demonstrate an accelerated method of deacetylation of CTA were carried out, resulting in phase pure cellulose II. A density functional geometry optimization allowed for the generation of an improved structural model for cellulose II. Calculated and experimental powder patterns for cellulose II have been submitted to the International Centre for Diffraction Data for inclusion in future releases of the Powder Diffraction File.