Analysis and evaluation of thermal hazards for 2,2′‐azobis (2‐imidazoline) dihydrochloride (<scp>AIBI</scp>) and its mixtures with incompatible substances

Abstract 2,2′‐Azobis(2‐imidazoline) dihydrochloride (AIBI) is a widely used initiator in emulsion polymerization. As a water‐soluble azo initiator, AIBI offers high initiation efficiency and has more environmental protection. However, its heat sensitivity poses a potential risk of fire or explosion. Additionally, the accidental mixing of incompatible substances may increase the risk of thermal runaway accidents during the storage and application of AIBI. In this study, the thermal properties of AIBI, AIBI with toluene, and AIBI with hydrochloric acid (HCl) were examined using differential scanning calorimetry (DSC) and adiabatic accelerated calorimetry (Phi‐Tech II). Kinetic triplet states were determined from experimental data using thermodynamic methods. The risk of AIBI and AIBI‐Toluene was assessed by semi‐quantitative analysis. Finally, the energy changes during the initial pyrolysis of AIBI and its mixtures were investigated by theoretical calculations. The results of the study emphasize the influence of impurities on the thermal hazards associated with AIBI and provide valuable theoretical insights for the protection of personnel and equipment.