| Abstract: | ![]()
The dissolution of cellulose in solutions of liquid ammonia and ammonium thiocyanate is discussed. Viscosity measurements on dilute solutions of cellulose in this solvent over a range of shear rates and shear stresses are reported. A four-bulb Ubbelohde suspended level viscometer was used for the measurements. Plots of log [η] versus log M gave Mark-Houwink coefficients of a = 0.95 and K = 6.686 × 10?5 at 25°C for [η] as dl/g. The Bloomfield equation was used to calculate effective bond lengths (b) from limiting viscosity numbers of cellulose in solutions of ammonia/ammonium thiocyanate and Cuene, respectively. Results indicate that cellulose may have similar configurations in both solvents and also that the ammonia solutions are true cellulose solutions. Miscibility of the cell- ulose/ammonia/ammonium thiocyanate solutions with organic solvents, such as glycerol, is also reported. Further, a few interesting characteristics of the liquid ammonia/ammonium salt solutions, discussed briefly, are the convenient boiling point, the rheological behavior, and the relatively high concentration of cellulose obtainable. |
