SOLUBILITY OF CELLULOSE-III IN SODIUM-HYDROXIDE SOLUTION

Studies on cellulose III solubility have been conducted in 8.5% NaOH s olution with and without the presence of added substances, such as acr ylamide, acrylic acid, acrylonitrile, and thiourea. The highest value of cellulose III solubility was obtained as a result of the introducti on thiourea and acrylamide in a 5% ratio of NaOH into NaOH solution. M oreover, dissolving conditions proved to be of great importance. Cellu lose III introduced into NaOH solution and repeatedly frozen and unfro zen three times dissolved 50% (dissolving with 5% thiourea). The solub le cellulose fraction showed significantly lower molecular mass in com parison with its insoluble fraction. Comparative studies on cellulose crystallinity using the CP/MAS C-13-NMR method showed a satisfactory c ompatibility of results with determinations obtained from the X-ray me thod. (C) 1993 John Wiley & Sons, Inc.