Colloidal Gibbsite Nanoparticle/Polyacrylamide Composites for Flame-Retardant Materials

Two-dimensional (2D) nanomaterials have many potential applications. Herein, 2D colloidal gibbsite (GS) nanoparticles, [γ-Al(OH) 3 ], dispersed easily in water, are used as an effective filler for polyacrylamide (PAM) to improve their thermal degradation behaviors for applied fields in flame retardants. A composite containing 10.0 wt % GS retains more than 30.8 wt % noninflammable residues after pyrolysis (900 °C). The kinetics and thermodynamics of PAM and GS/PAM have been elaborately investigated using thermogravimetric analysis for the first time. The kinetic (activation energy, pre-exponential factor, reaction order) and thermodynamic (Δ H, Δ G, Δ S ) parameters during the major decomposition zone (330–460 °C) are determined by applying Van Krevelen, Horowitz–Metzger, Coats–Redfern, Broido, Madhusudanan, Arrhenius, and Bagchi models. The results show that as the content of GS or acrylamide in composites increases, their activation energy increases or decreases, respectively. For a composite containing 10.0 wt % GS and 30.0 wt % acrylamide, compared to PAM, the activation energy reaches the highest value of 362.720 kJ/mol, the ignition time is 125 s longer, and the peak heat release rate and total heat release diminish by 44.5 and 68.8%, respectively. The presence of a kinetic compensation effect is also evident. The as-prepared GS/acrylamide is an aqueous dispersion and is hence easily surface-coated onto other flammable foams or materials by blade-coating or dipping. Our studies contribute to understanding 2D GS-blended nanocomposites in their applications as flame retardants or fire-resistant membranes.