The adhesion of rubber an industrial problem

Abstract

This thesis is concerned with an industrial problem: in the manufacture of rubber tyres, unvulcanized rubber comes into contact with vulcanized rubber surfaces, and the two rubbers adhere. A method of treatment which eliminates this undesirable clinging action is necessary. Dunlop Rubber Co. Ltd., found that bromine in carbon tetrachloride and N - bromo-succinimide in methyl ethyl ketone prevent adhesion for a certain period of time. The problem considered is the mechanism by which treatment of the rubber with bromine and N - bromosuccinimide causes the rubber to become smooth and the most satisfactory way in which this can be achieved on the shop floor. The reaction of bromine and iodochloride with natural rubber has been considered as a model system. It has been found that these two halogens attack the rubber in such a way as to saturate the double bonds. The product rubber has the properties of hard, inert, nonelastic material with a smooth surface. In the early stages of the reaction, the rate was governed by the rate at which the solvent was imbibed into the rubber and it has been found, that bromine is the better reagent. With N - bromosuccinimide the reaction proceeds via the attack of molecular bromine on the double bonds of natural rubber. Application of these solutes and their solvents on the shop floor is difficult owing to their toxicity, and methods of overcoming this have been discussed.