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.

A novel intumescent fire‐retardant coating formulation has been developed by taking advantage of the inherent stability of large cyclic polyphenols (e.g., tannic acid) to remove the need for a dedicated blowing agent, specifically melamine. Cone calorimetry data indicate a lower fire growth rate (FIGRA) (5.0 ± 1.3 vs. 2.4 ± 0.7 kW m⁻² s⁻¹) upon removal of melamine. Total smoke release (TSR) increases following this removal (178 ± 21.4 vs. 305 ± 13.2 m² m⁻²), which indicates the role of tannic acid in gas generation. Thermogravimetric analysis resulted in similar residue yield from the examined systems (36 ± 1.3% vs. 34 ± 1.7%) despite removal of a dedicated blowing agent. These results indicate that tannic acids multistep degradation allows it to behave as both a char forming and blowing agent in intumescent systems. The observed reduction of acid loading between the melamine‐tannin system and the melamine‐free composition (15.6% vs. 10.6% wt. ammonium polyphosphate, respectively) is also significant. Tannic acid occurs in agricultural waste products, which is encouraging for the pursuit of sustainable chemistry and addressing potential adverse health effects in humans combined with reducing the overall phosphorous loading.Highlights: Melamine was removed from the intumescent without compromising stability. The resulting intumescent char was stronger despite less expansion. Tannic acid is attributed as both the charring and blowing agent. The tannin‐based coating requires a lower acid loading for similar performance.