Butyl rubber solution directly can be obtained in the synthesis of butyl rubber by solution process,which shortens the bromination steps. While in this process it is difficult to remove the isobutylene monomer in butyl rubber solution completely because of the great airtightness of butyl rubber.The mass concentration of residual isobutylene in butyl rubber solution was effectively determined by Headspace Gas Chromatography. The effects of residual isobutene monomer on bromination of butyl rubber were investigated. The results showed that the bromine content decreased rapidly, while the mole ratio of structure II and structure III increased with the increasing of the concentration of isobutylene.

BIIR was synthesized by solution method and antioxidant 1520 was added in the process. In order to investigate the impact of antioxidant 1520 on the thermal degradation behavior of BIIR, the TG was used to investigate the thermal decomposition of BIIR under different heating rate. Kissinger method and FlynnWallOzawa method were used to calculate the apparent activation energy of the nonisothermal decomposition reactions of BIIR, and CoatsRedfern equation was used to deduce the thermal decomposition mechanism of BIIR added antioxidant 1520 before and after. The results showed that the activation energy calculated by Kissinger and FlynnWallOzawa methods was consistent, and the addition of antioxidant 1520 significantly improved the thermal degradation reaction apparent activation energy of BIIR. It can be deduced from the CoatsRedfern equation that the addition of antioxidant 1520 made the thermal decomposition reaction mechanism of BIIR change from the phase interface reaction mechanism into more complex chemical reaction mechanism of tertiary.