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Cellulose Studies : XII. The Degree of Polymolecularity of Acid-Modified Celluloses

Mehta, P.-C., Pacsu, Eugene
Textile research journal 1949 v.19 no.11 pp. 699-703
acetone, cellulose, cotton, fabrics, hydrolysis, nitrates, rayon, textile fibers
For the determination of the degree of polymolecularity in acid-modified celluloses the nitrates of hydrocelluloses from native cotton, surgical cotton, and viscose rayon were frac tionated from dilute acetone solutions. The results indicate that a large proportion of the hydro celluloses are uniform in that almost 33% of the methanolyzed native cotton consists of mole cules with D.P. 252, about 70% of the hydrocellulose from surgical cotton has D.P. 260, and some 36% of the material from viscose rayon possesses D.P. 62. Moreover, the most important fractions were found to be integral multiples of the assumed "limit hydrocellulose" with D.P. 64. Integral- and mass-distribution curves were constructed from the experimental data according to the procedure outlined by Schulz and were compared with the theoretical mass-distribution curves calculated on the basic assumption of random hydrolysis of a long-chain molecule with uniform hydrolyzable bonds. In all three cases the experimental curves show pronounced peaks, which can be readily interpreted only on the basis of the new concept of cellulose structure.