In situ and ex situ synthesis of poly(vinyl alcohol)-Fe3O4 nanocomposite flame retardants

Application of flame retardants is limited because of environmental requirements. This work introduces conventional magnetic nanoparticles as a new class of nontoxic and effective flame retardant. Fe3O4 enhanced both the thermal stability and flame retardant properties of a poly(vinyl alcohol) matrix. Nanoparticles were synthesized via a simple precipitation reaction without using an inert atmosphere at room temperature. The effects of different precursors and acrylamide on the morphology of the products were investigated. Nanoparticles exhibited a ferrimagnetic behavior at room temperature. To prepare the magnetic nanocomposite, Fe3O4 nanoparticles were added to the poly(vinyl alcohol). In the presence of a flame, the magnetic nanoparticles remained together, showed resistance to dripping and protected the polymer matrix. Dispersed nanoparticles play a role of a magnetic barrier layer, which slows product volatilization and prevents flames and oxygen from reaching the sample during decomposition of the polymer. (C) 2016 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.