Study On The Effect Of The Bromination Conditions On The Property Of The Brominated Hutyl Rubber

Brominated isobutylene-isoprene rubber(BIIR)is a new popular material that has been widely used for electrical cable protection,auto tire casing and medical production in recent years.Due to the monopoly of foreign technology,the current technology for BIIR production is relatively immature and still on the groping stage in China.In addition,the stability of comprehensive performance is still unsatisfactory.Thus,the BIIR in the domestic market mainly depends on imports.Therefore,it is important to investigate the effects of bromination reaction conditions on the BIIR performance.The BIIR was manufactured using solution method.In briefly,brominated butyl rubber was firstly dissolved in hexane,and then stirred with liquid bromine.The BIIR was generated with substitution reaction.The BIIR samples were further characterized,and their performance metrics were obtained,such as bromine content,unsaturation,relative molecular weight,BIIR structure,Mooney viscosity,and vulcanization properties.We also investigated the influences of technology parameters(e.g.reaction time,temperature and additives dosage)on the microscopic and macroscopic properties of BIIR.Based on the attained performance metrics,the BIIR with better comprehensive performance was obtained.The results provided the basic data for the operation condition of BIIR production.The result showed that the BIIR with superb performance was obtained at the reaction time of 7 min,temperature of 40?,epoxy soybean oil dosage of 1.6%,and calcium stearate dosage of 2.5%.The performance metrics of the BIIR were as followed:bromine content,2.0%;viscosity,35;unsaturation of 0.90,molecular weight,3.292;vulcanization time,8.9.Under the optimized condition,the bromination reaction was relatively complete,and the three microstructures of BIIR were in a relatively stable state.Among them,the content of the bromo primary allyl structure(structure ?)and the bromo primary allyl structure(structure ?)tend to be stable.This could be the reason that the primary halogen in BIIR was more stable than the secondary halogen.The primary halogen was difficult to be placed by the secondary halogen.The number of primary substitutions in the substitution reaction was positive related with vulcanization rate.The more substitutions by bromo primary allyl enhanced vulcanizing adhesion with other unsaturated rubbers,which was favorable for mix and match.