Ultrasonic degradation of cellulose nitrate: Relation between initial and final average and distribution of DP

Abstract

Abstract Cellulose nitrates of average DP 130 to 2400 and of various DP distributions were degraded in ethyl acetate solutions by ultrasonic energy at 400 kilocycles. A method of comparing degradation rates of samples degraded at different concentrations is described. The degrees of degradation found were in accord with the theory of Schmid and co‐workers, and the minimum degradable chain length was calculated to be 980 DP in this system. Where compared with degradation by alkaline aging, ultrasonic degradation gave a much more uniform chain length distribution. After ultrasonic treatment, 60% of the sample was of DP 700 to 1200, while the alkaline aged sample had less than 40% in this same range and a much larger amount of short chain length material. The results do not give any indication of the presence of any physically or mechanically weak chain links at any interval near 500 DP.