| Aging behavior of brominated butyl rubber(BIIR) were studied in thermal-oxidative,UV irradiation,solvent immersion and salt spray environments,and the mechanism in the environment of thermal-oxidative and UV irradiation were predicted.Different Evaluating indicators were adopted to predict the service life of BIIR in various environments.In thermal-oxidative environment, crack and powder were produced on the surface of BIIR after aging.The higher the temperature and the wider the crack.When the temperature were during 25～60℃,the crosslink denstiy,hardness,tensile strength and elongation at break rarely changed with aging.The hardness and crosslink density increased,while the tensile strength and elongation at break decreased at 70℃and above with the elongation of aging time.When the temperature reached 110℃,the hardness increased,while the tensile strength and elongation at break were almost lost,and crosslink density began lower.The thermal-oxidative stability was deteriorated after aging in this environment.From the results of ATR-FTIR spectroscopy it can be concluded that the increasing strength of the peak of carboxy groups and hydroxyl groups of BIIR,but the decreasing of double bonds, isopropyl groups and methylene groups of its with the increasing temperatures. The bond energy of -C-Br is low and first fractured in the process of BIIR thermal decomposition,the reaction of hydrogen bromide off happened. Then, the main strand broke and formed -C-C-bond.In the late period,the oligomers at the presence of oxygen generated hydrocarbon gas molecules. In the UV irradiation environment,crack and powder appeared on the surface and the crack density increased gradually with aging.The hardness and crosslink density tended to increase while the tensile strength and elongation at break decreased.The thermal-oxidative stability was not deteriorated upon exposure to UV. The spectroscopy of ATR-FTIR illustrated oxygen took part in the aging and the increasing strength of the peak of carboxy groups and hydroxyl groups,but the decreasing of methylene groups and isopropyl groups of BIIR with aging-C-Br bond in BIIR is low and the bond was broken first to generate gas under UV irradiation. After that peroxide reaction center formed in the position of a of methyl hydrogen connected with double bond resulting in strand breaks later.Under 50℃, the swelling rate of the brominated butyl rubber reached more than 100% after 10 days in 93# gas, and the surface was sticky. It indicated the oil resistance of BIIR was poor.Under the same temperature in cyclohexane as the non-polar solvent, swelling rate was 96.2% after 7 days and the surface did not appear sticky,while in polar solvents ethanol, the swelling rate of BIIR was 0.45% after 6 days almost insoluble or swelling.In the environment of salt spray at 35℃, with increasing of aging time, the surface of BIIR became uneven and cavity, and micro-cracks. Rate of quality change increased.The hardness gradually increased, while the tensile strength and elongation at break decreased gradually.With the elongation of time,these change gradually flattened.In thermal-oxidative environment,the service life of BIIR is 68d,107d,63d and 54d when crosslink density,hardness,tensile strength and elongation at break are used as evaluating indicators,respectively.In UV irradiation environment,its service life is 47d,540d,41d and 34d when crosslink density,hardness,tensile strength and elongation at break are used as evaluating indicators,respectively. In the solvent environment, selected the rate of quality change as evaluating indicator, its service life in the 93# gasoline and in cyclohexane is 1d respectively, while in ethanol is longer. In the salt spray environment, the service life of BIIR is 24195d,4359d and 622d when rate of quality change,hardness and elongation at break are used as evaluating indicators respectively,and its service life is longer when tensile strength as evalutating indicator.
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