Intumescent coatings expand upon exposure to a flame to create a protective char layer between the flame and underlying substrate. Widely used commercially, these coatings are applied notably to steel load-bearing beams, significantly extending their time to failure. Boric acid has proved to be a particularly effective additive in the formulation in these coatings, although regulatory concerns are driving an urgent need for more environmentally friendly additives. We report here the characterization of poly(acrylic acid) (PAA) for its use as a novel material in flameretardant and intumescent coatings. Thermogravimetric analysis (TGA) and microscale combustion calorimetry (MCC) were performed on the novel flameretardant additives to evaluate individual degradation mechanisms and heat release rates. Promising compositions were immobilized in an epoxy binder and formulated with other intumescent additives such as ammonium polyphosphate (APP) and melamine (MEL) to evaluate performance in a coating system. These formulations were then evaluated via quantitative cone calorimetry. Particular PAA-containing formulations show peak heat release rates (PHRR) and total heat release (THR) of 283 kW/m 2 and 50.5 MJ/m 2 , respectively, which compare favorably to data for BA-containing systems, specifically PHRR = 229 kW/m 2 and THR = 43.1 MJ/m 2 . Results showed promise and need for further investigation into PAA as a multifunctional additive for use in flame-retardant and intumescent coatings.

Tannic acid (TA) has gained increased attention in recent years for its application in fire safety due to its natural abundance and char‐forming ability. In this paper, TA‐based composites were developed and evaluated against control composites containing pentaerythritol (PER), a common intumescent char‐forming agent. Individual component analysis was performed to provide a fundamental material understanding, followed by compounding in epoxy resin with other intumescent ingredients for intumescent testing (especially compared against PER control). In all TA systems, time to failure was elongated from seconds or minutes to over 15 min (up to 27 min). Quantitative analysis followed using cone calorimetry. TA composites displayed lower peak heat release values (211 vs. 108 kW/m2), lower total heat release values (37.2 vs. 24.4 MJ/m2), and lower fire growth rates (2.43 vs. 1.27 kW/m2s−1) relative to PER composites. X‐ray photoelectron spectroscopy analysis revealed that TA char is more carbonaceous, containing 54.71 at% C (relative to only 39.63 at% C in PER char). This work presents TA‐containing composites that offer superior fire protection as compared to previous reports using TA composites and hence offer significant advancement in fire protection related and packaging industries.