Studies of chlorinated polyisobutenes. Part I. Investigations of structure by proton magnetic resonance and of thermal stability by thermal volatilization analysis

Polyisobutene was chlorinated in carbon tetrachloride solution at 60°C. with radiochlorine, and the degree of chlorination was determined radiochemically. The extent of chlorination was varied by using a wide range of chlorine/polyisobutene ratios in the reaction mixture. The products were examined by PMR spectroscopy, which showed that both methyl and methylene groups were chlorinated but that the methylene hydrogens were more readily substituted and some disubstitution of the methylene groups occurred. The effect of chlorination on the thermal stability compared to the original polymer was studied by the new technique of thermal volatilization analysis. All the chlorinated derivatives were found to degrade at lower temperatures than polyisobutene. The stability dropped progressively as the chlorine content was increased to one chlorine atom per isobutene unit and then showed less change with further increase in chlorine content.