New nitrogen‐rich heterocycles for organo‐modified bentonites as flame retardant fillers in epoxy resin nanocomposites

New flame retardant organo‐modified bentonites, based on nitrogen‐containing compounds were synthesized via an ion exchange process starting from pristine bentonite with acidified 6‐(4‐butylphenyl)−1,3,5‐triazine‐2,4‐diamine (BFTDA) and 11‐amino‐N‐(pyridine‐2yl)undecanamide (APUA). The amount of nitrogen rich organic modifier in the obtained organoclays (Bento‐BFTDA and Bento‐APUA) determined by TGA is around 0.4 mmol/g for both samples. With the aim to study the effect of these additives on a commercial epoxy resin, nanocomposites containing 3 and 5 wt% of the nanofillers were prepared by solventless addition to the epoxy resin formulation. For the sake of comparison similar nanocomposites with plain unmodified bentonite were produced. The nanocomposite's thermo‐mechanical properties of all the produced samples were measured and they resulted slightly improved or practically unaffected. Finally, when the flame behavior was assessed in the cone‐calorimeter, an encouraging decrease of 17% in the peak heat released rate (pHRR) was obtained at 3 wt% loading level with Bento‐APUA. These promising results suggest that the APUA modified organoclay, prepared with low cost reactants and mild reaction conditions, might efficiently act as a flame retardant. POLYM. ENG. SCI., 57:621–630, 2017.