Development of hexagonal boron nitride and zinc oxide nanocomposite for fire retardant and anti-electromagnetic construction coatings

Abstract

Fire retardant and anti-electromagnetic construction material with nanoscale additives are suitable for contemporary buildings and infrastructures. This work adopts an effective homogenizing approach to develop nanocomposites for fire retardant and anti-electromagnetic construction coatings. The nanocomposites composed of two-dimensional (2D) hexagonal boron nitride (h-BN) sheets and zero-dimensional (0D) zinc oxide (ZnO) nanoparticles. Further, these nanocomposites (2D + 0D) were combined with a sodium metasilicate and gypsum matrix for evaluating the flame retardancy and EMI shielding properties. The enhanced flame retardancy and EMI shielding characteristics were observed, when utilized in construction coatings on both wooden and wallpaper substrates. The results of studies on fire injection at 1050 °C indicate that adequately engineered h-BN + ZnO nanocomposites significantly mitigate flame propagation and charring, consequently decreasing carbonization regions. Furthermore, thermal investigation of the nanocomposite coating showed extensive char residue (83.5%) at 800 °C, indicating increased thermal insulation due to the composite's excellent architectural design. Nanocomposite coatings exhibit a substantial reduction in both electromagnetic and electric fields, demonstrating their effectiveness in EMI shielding. Especially, h-BN:ZnO (3:1) coatings, suggested best fire coating (carbonization fraction) and higher electromagnetic absorption. This improved EMI shielding performance attributed to the design of the nanocomposites, which played a crucial role in tuning resistance and dielectric loss, primarily facilitating electromagnetic absorption by ZnO nanoparticles.