Abstract
The comparative investigations on the behaviors of cellulose in phosphoric acid, in xanthation, and in acetylation were carried out microscopically. The similarity of swelling state was noticed in phosphoric acid and xanthation. The behavior of cellulose in acetylation, however, differed from those in the former two reagents, The fact may be ascribed to the higher rate of degradation and solubilization of cellulose than the rate of access (i. e. Penetration and esterification) of acetylating reagent. It was noticed that the susceptive “weak points” in outer layer of fiber were the cause of “baloon like swelling” in phosphoric acid or xanthation, and they also caused cracks perpendicular to fiber-axis in acetylation. It was also stated that the swelling test with phosphoric acid is a convenient method to know the inhomogeneity of accessibility in interfiber or intra-fiber and the reaction “Processability” (cf. R. C. Blume et al.; Tappi, 37, 28 (1954)) of dissolving pulp in xanthation and acetylation.
