Inter- and intramolecular order in regenerated cellulose

✍ Scribed by A. J. Pennings; W. Prins; R. D. Hale; B. G. Rårnby

• Publisher: John Wiley and Sons
• Year: 1961
• Tongue: English
• Weight: 773 KB
• Volume: 5
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1961.070051810

✦ Synopsis

Abstract

Cellulose was regenerated from technical viscose as bulk gels and thin films (never dried) and then conditioned by repeated swelling with sodium hydroxide solutions and steam treatments. These extraction and conditioning treatments of the gels increased the crystallinity and decreased the accessibility to water as measured by x‐ray, infrared, and density measurements. The density of the gels increased more during these treatments than one would expect from the increase in crystallinity as measured from x‐ray diffraction. Supported by the combined density, infrared, and D~2~O‐exchange data, this was taken as evidence that the conditioning also gives a closer packing or an increased order in the so‐called amorphous regions. Both steam‐conditioning and drying decreased the accessibility of thin films as measured by a combination of infrared analysis and swelling with sodium deuteroxide solutions in heavy water (NaOD in D~2~O). Reports in the literature that regenerated cellulose is completely accessible in dilute aqueous alkali solutions (about 1%) have not been verified. The intensity ratios of the different infrared absorption bands were measured during the gradual swelling and exchange with NaOD of increasing concentrations from 1 to 16% in D~2~O. The few data available now seem to indicate that hydroxyl groups assigned to intrachain hydrogen bonds in crystalline regions are more resistant to deuterium exchange than hydroxyl groups assigned to interchain hydrogen bonds. Based on these studies the concepts of crystallinity, order, and accessibility to water and swelling agents for regenerated cellulose are discussed.