STUDIES ON CELLULOSE PHOSPHATE

Effects of cellulose crystallinity on the preparation of water or N-NaOH soluble cellulose phosphate were studied. First it was confirmed that soluble Na cellulose phosphate could be obtained when the noncrystalline cellulose is used as raw material. Then, four kinds of low crystalline cellulose were prepared, and the phosphorylation under nearly the same condition was made. It was found that some portions of the product were soluble in N-NaOH, and in all the case the soluble portions showed a higher degree of esterification than the insoluble parts. Crystallinity of the soluble parts were ca. 40% for all the samples, regardless of the crystallinity of the original cellulose used, and from these results it became clear that this reaction advances not only in the amorphous region, but in the crystalline region, though the rate is very slow. From the result shown in a figure of percentage of soluble parts versus the degree of cellulose crystallinity, it would be expected under the condition employed that the cellulose having less than 20% of crystallinity will result in completely soluble cellulose phosphate, and the cellulose with more than 50% crystallinity, completely insoluble one.