Analysis of the thermal decomposition of a fire-retardant intumescent coating based on oxidized graphite

Introduction. The development of effective intumescent fire-retardant coatings (FRC) for steel building structures requires a deep understanding of their thermal decomposition mechanisms. Modification of classic fire-retardant systems, in particular by adding intercalated graphite to the formulation, is aimed at improving its thermal stability and fire-retardant effectiveness. A key tool for studying these processes is synchronous thermal analysis using thermogravimetry (TG) and differential scanning calorimetry (DSC) methods.

Aim. Study of the mechanism and kinetics of thermal degradation of a thermally expanding fire-retardant coating based on an epoxy dianic resin binder and an amine hardener, with oxidized graphite as the main intumescent filler in inert (argon) and oxidative (oxygen) atmospheres using TG/DSC methods for assessing its fire-retardant potential and identifying the key stages of thermal decomposition.

Materials and methods. Thermal analysis of the coating samples was carried out using a NETZSCH STA 449 F5 synchronous thermal analyzer in argon and oxygen atmospheres at a heating rate of 10 K/min up to 1000 °C. Qualitative characteristics, including thermal effects, were determined, and a comparative analysis of the coating’s behavior under pyrolysis and oxidation conditions was performed after processing the obtained data using Proteus Thermal Analysis software.

Results. Presented are the results of studies of the thermal properties of a thermally expanding fireretardant coating based on an epoxy dianic resin binder and an amine hardener, with oxidized graphite as the main intumescent filler, as well as the oxidized graphite itself. The thermal properties were determined in the temperature range from 24 to 1000°C. It was determined that the thermal decomposition of a thermally expanding fire-retardant coating based on an epoxy dianic resin binder and an amine hardener and oxidized graphite as the main intumescent filler is multistage. The critical temperature of the coating transition to an active state, corresponding to the initiation of intumescence, has been quantitatively determined.

Conclusions. It has been confirmed that the oxidized graphite in the analyzed fire-retardant coating provides a high endothermic effect, which confirms the effectiveness of the fire-retardant coating in fire conditions. The data obtained allow to quantitatively assess the impact of various decompostion stages in the fireretardant effectiveness of the formulation.

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