Hierarchical NiO/Al2O3 nanostructure for highly effective smoke and toxic gases suppression of polymer Materials: Experimental and theoretical investigation

Abstract

There is still a lack of in-depth investigation of the suppression mechanism for polymeric materials. Herein, based on the density functional theory (DFT) study, the flame retardancy, smoke, and toxic gases suppression mechanisms of hierarchical NiO/Al2O3 nanostructures in thermoplastic polyurethane (TPU) are in-depth revealed. The incorporation of NiO/Al2O3-S into TPU leads to a significant reduction in total smoke release by 41.9%, and peak CO production rate by 47.8% (Cone calorimetry test results). Besides, the NiO/Al2O3-S results in a remarkable decrease of 48% in Dsmax during the smoke density test. Most importantly, based on DFT calculations, incorporating catalysts enhances the adsorption energy of CO, O2, and CO2 on the surface of TPU nanocomposites, thereby facilitating CO oxidation reactions. This is conducive to reducing flue gas emissions and toxicity levels. This work introduces DFT into the flame retardancy research of polymer materials, thus providing reliable guidance for designing highly effective smoke suppressants.