Tannic acid based super‐intumescent coatings for prolonged fire protection of cardboard and wood

Abstract 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.