Optimisation of bio-based PIN intumescent

Heat barrier effect of tannic acid - ammonium polyphosphate (APP) intumescent increases with porosity and char. These PIN FR compounds were tested in DGEBA resin with a polyamine hardner. Heat transfer was tested using heat flow meter tests with the intumescent coating on a metal sheet subjected to a methane torch. The intumescent layer’s heat barrier effect increased as its porosity increased (measured by SEM scanning electron microscopy with MATLAB-based image analysis) and with formation of a thermally stable char layer at around 400°C. This research is supported by a pinfa-NA scholarship (see pinfa Newsletter n°170).

“Thermal Insulation Performance of Epoxy-Based Intumescent Coatings: Influence of Temperature-Induced Porosity Evolution on Heat Transfer Resistance”, T. Hafiz et al., Polymers 2025, 17, 1426, https://doi.org/10.3390/polym17111426  Photo: Taher Hafiz.