A comprehensive study has been made of the effect of time on the weight loss and degree of polymerization of ten representative samples of cellulose using both mild (5.0 l\f hydrochloric acid at 5°, 18°, and 40°C .) and drastic (2.5 N and 5.0 N hydrochloric acid at boil) conditions of hydrolysis. The samples were purified cotton, bleached cotton linters, cotton linters pulp, wood pulp, textile rayon, tire yarn, Fortisan, Fiber G, and two experimental rayons.

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Viscosity-concentration data are given for five samples of purified cellulose representing the degree of polymerization range from 300 to 3000. On plotting the data on semilogarithmic paper, linear relationships were found to exist, in each case, between (1) the viscosity function 22 ancj concentration, and (2) the relative viscosity function measured at 0.5% concentration and the degrees INDUSTRIAL AND ENGINEERING CHEMISTRY

Milder conditions of hydrolysis than have been heretofore generally used to characterize cellulosic structures chemically were employed for the purpose of comparing the hydrolytic accessibility of native and regenerated structures, respectively. It is assumed that the acces sibility of the fine cellulosic structure is related to the rate of drop of the average degree of polymerization of the cellulose with time of treatment. Using 5 N HCl at 18°C, the following samples of cellulose were evaluated: - 1. Cotton linters and acid-pretreated cotton linters, respectively, before and after non- degradative solution and regeneration. 2. Cotton linters and acid-pretreated cotton linters, respectively, before and after swelling in 18-percent NaOH at 18°C. 3. Viscose rayons made from cotton linters and acid-pretreated cotton linters, respectively.