The Stability of Chlorinated Rubber and Its Fractions

Abstract

Abstract (1) In ultraviolet rays decomposition occurs in the upper surface of a layer of chlorinated rubber. (2) The amount of chlorine split off from a common commercial specimen of chlorinated rubber when heated dry for 30 days at 100° C was about 0.25 per cent. For the greater part, the chlorine was free of hydrogen chloride. (3) The rate of decomposition when dry heating was applied at 100°, 130° and 150° C leads to the conclusion that the speed of reaction diminishes rapidly at degrees below 100° C until there is soon no reaction at all. (4) The amount of chlorine split off when chlorinated rubber was heated in water at 100° C was about five times as large as when dry heating was applied. (5) From the curves indicating the amount of chlorine split off during “wet”and “dry”heating at 100° C, it is possible to calculate quantities which may be regarded as the maximum amounts of chlorine which can be split off from the respective specimens. These amounts are twice as large when the chlorinated rubber is heated wet as when dry heating is applied; with a given normal specimen about 1.5 per cent was obtained in wet heating. Only in one of eight specimens was a greater quantity found, viz., 3 per cent. (6) In a certain specimen 10 per cent of carbon tetrachloride was found. The splitting off of chlorine is not caused by decomposition of this substance.