Halloysite nanotubes as smart flame retardant and economic reinforcing materials: A review

Halloysite nanotubes (HNTs) are precious clay materials with a hollow nanotubular structure. They are used up to date latent for synthesizing polymeric nanocomposite because of high surface area, low cost and the natural existence. HNTs nanocomposites have been fabricated using different methods; however, the widely used is melt mixing technique. The functionalization of HNTs is very crucial to achieve the well dispersion in polymer. The flammability, thermal stability and mechanical properties were improved by the addition of HNTs. Because of the tube shape of HNTs, it can help in trapping the flammable volatiles besides, HNTs can form a strong barrier on the surface of polymer against heat and mass transport processes. The essential aim of this review is the latest researches on modified halloysite nanotubes as an efficient flame retardant for various polymer nanocomposites and their influence on the mechanical properties and thermal stability.