Calorimetric Techniques Combined with Various Thermokinetic Models to Evaluate Incompatible Hazard of <i>tert</i>-Butyl Peroxy-2-ethyl Hexanoate Mixed with Metal Ions

Abstract

tert-Butyl peroxy-2-ethyl hexanoate (TBPO), an organic peroxide broadly used as initiator for polymerization of ethylene, styrene, methyl methacrylate, and acrylonitrile, has the characteristic of triggering a highly exothermic reaction. Mixing with a contaminant, such as metal ions, may result in a runaway reaction and acceleration decomposition under an abnormal situation. We investigated how Cu2+, Ni2+, and Fe2+ individually affected the thermal decomposition of TBPO. Our aim was to explore the thermal hazard of TBPO mixed with metal ions by calorimetric techniques combined with thermokinetic models. We employed nonisothermal and isothermal calorimeters to determine various thermokinetic and safety parameters, including exothermic onset temperature (To), peak temperature (Tp), final temperature (Tf), heat of decomposition (ΔHd), and maximum heat flow (Qmax) by differential scanning calorimetry (DSC) and thermal activity monitor III (TAM III). Moreover, the isothermal and nonisothermal kinetic models were applied to predict time to maximum rate under adiabatic conditions (TMRad), adiabatic temperature rise (ΔTad), time to conversion limit (TCL), control temperature (CT), emergency temperature (ET), and self-accelerating decomposition temperature (SADT). From the experimental results, Cu2+ could significantly affect TBPO to increase Qmax more than 2-fold as compared to the rest and T0 was advanced as well. Therefore, TBPO contamination by Cu2+ should be avoided during every stage of the manufacturing process.