Copolymer of isobutylene and para-methylstyrene

Brominated Copolymer of Isobutylene and para-Methylstyrene (BIMSM) 73... 

Brominated copolymer of isobutylene and para-methylstyrene (DIMS) is the latest new class of synthetic rubber that has been developed for the rubber industry. The sole producer of this new class of elastomer is ExxonMobil, which commercialized it successfully under the trade name Exxpro in the first decade of this new century. The advantage of this new polymer class vs. bromobutyl rubber is that this new elastomer possesses a completely saturated backbone and possesses more reactive benzylic bromine functionality than the bromine sites on the conventional bromobutyl backbone. This means that DIMS reportedly gives superior performance in service vs. BUR. This superiority is shown as better high-temperature resistance, better aging stability than either BUR or EPDM, better weathering resistance, and better ozone resistance. Also, BIMS provides the potential of imparting superior air permeability resistance. 

This new commercial rubber is produced from the carefully controlled bromination of the copolymer of isobutylene and para-methylstyrene, which forms a terpolymer as shown in Figure 4.9. 

ExxonMobil first commercially Introduced DIMS (bromlnated copolymer of Isobutylene and para-methylstyrene) In the 1990s. In 2004, ExxonMobil and Yokohama, through a cooperative arrangement, announced the development of a new TPV based on DIMS and nylon to produce a less expensive tire Innerllner with better air permeability resistance and less weight. This new TPV can actually be blown Into a film to be used as the innerliner to reduce the loss of air from the tire. This film Is made by ExxonMobil at their Pensacola, Florida, mixing plant, where the dynamic vulcanization process Is carried out. 

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