The Study Towatds The Process For Direct Bromination Of Butyl Rubber Synthesized By Solution Method

This paper studied on the process for direct bromination of butyl rubber synthesized by solution method. Starting from synthesizing the butyl rubber by solution method, the effects of the components of water/chlorinated ethylaluminum initiator system on synthesis of butyl rubber were investigated. The feasibility of terminating the polymerization reaction by water instead of methanol and the desired amount of water was discussed. A method for determination of the mass concentration of residual isobutylene in butyl rubber solution by headspace gas chromatography was described, and the effects of residual isobutene and water on bromination of butyl rubber were investigated. The contents of aluminum element of butyl rubber were measured by ICP-AES. Finally, the butyl rubber solution synthesized by4L reactor was brominated directly, the bromination processing conditions was further adjusted by changing the amount of bromine.The results showed that:(1) The concentration of water in the initiation system determined the number of active centers, and had a significant effect on the molecular weight and distribution of butyl rubber.(2) Headspace gas chromatography can effectively determine the concentrations of residual isobutylene and chloromethane in butyl rubber solution. The bromine content of BUR decreased rapidly with the increase of the concentration of isobutylene, and the mole ratio of structure Ⅱ and structure Ⅲ increased.(3) The initiator can be deactivated when the concentration of water in the system was more than0.33wt%, and the bromination reaction was not affected by water when it was less than0.5wt%, so using water to terminate the polymerization reaction is available.(4) All the butyl rubbers had a different degree of aluminum residues, the butyl rubber synthesized by ourselves and unwashed had a higher content of aluminum than butyl rubber product.(5) The molecular weight and unsaturation of butyl rubber synthesized by the4L reactor can meet the requirements of bromination, the bromine content and structure Ⅲ of bromobutyl rubber increased with the increase of the amount of bromine.