Abstract
Powdered Cellulose is high alpha-pulp hydrolyzed to the crystalline region and pulverized by mechanical process. High-alpha was hydrolyzed with nitric acid and the effects of hydrolytic conditions (concentration of nitric acid, time and temperature) on the degree of polymerization and carboxyl content of the hydrolyzed pulp were examined mainly from the standpoint of the manufacture of powdered cellulose.
(1) From the viewpoint of the degree of polymerization of the hydrolyzed pulp, the suitable concentration of nitric acid is about 5 to log (10g) /100cc and the suitable time of hydrolysis is about 0.5 to 1 hour at the hydrolytic temperature of 90°C. It is possible to reuse the spent liquor by making up for the loss of nitric acid of the previous hydrolytic process.
(2) In case of the hydrolysis with nitric acid solution at the concentration of 0.1 g/100 cc at the hydrolytic temperature of 150°C and treatment of 3 hours, the degree of polymerization of the hydrolyzed pulp is nearly equal to that of the pulp hydrolyzed at 90°C, 10 g nitric acid/100 cc and 3 hours.
(3) Only a little formation of acidic oxidized cellulose takes place at the mentioned hydrolytic processes with dilute (under 10 g/100 cc) nitric acid.
(4) The stronger the condition of nitric acid treatment is, the easier pulverizes the acid treated cellulosic fibre and the more crack can be observed on the surface of the fibre.
