Recent advancements in nanostructured flame-retardants: Types, mechanisms, and applications in polymer composites

Abstract

Nanostructured flame-retardants offer an innovative approach to improve the fire safety of materials while addressing performance, environmental, and health challenges associated with traditional flame-retardants (FRs). By utilizing nanoscale FRs such as CNTs, nanoclays, nanoparticles, graphene, and metal-organic frameworks, unique flame retardancy mechanism can be obtained. Nanostructured flame-retardants enhance the fire resistance of polymer and polymer composites through heat dissipation, barrier effects, and char promotion, significantly reducing heat and gas transfer. Furthermore, the high specific surface area of nanostructured flame-retardants ensures effective dispersion within the polymer matrix without compromising thermal or mechanical properties. These materials also provide multi-functional properties such as electrical conductivity and thermal conductivity along with flame retardancy. Due to its multi-functional properties, these materials have various applications in different industries such as construction, electronics, automotive, and aerospace. However, challenges such as compatibility with polymers, potential environmental impacts and scalability are the critical areas, which need more focus in ongoing research. This review is mainly focused on nanostructured flame-retardants and their types, mechanisms and applications of flame-retardant polymer composites, emphasizing recent advancements. It also highlights their role in improving material sustainability and discusses challenges and future directions. Nanostructured flame-retardants offer a promising path toward safer, more efficient, and sustainable fire-resistant materials, meeting the increasing demand for multifunctional and ecofriendly solutions across key industries.