The synergistic effects between organophilic montmorillonites and graphene in poly(vinyl alcohol) based nanocomposites reduce the intrinsic flammability of these materials

Abstract A new approach has been developed to improve the dispersion of reinforcements in order to optimize the properties of nanocomposite materials based on poly (vinyl alcohol) (PVA) matrices. The approach consists of combining epoxy-functionalized graphene with organophilic clay (Mt@HTAB). X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM) reveal adequate dispersion of graphene sheets and clay layers throughout the PVA matrix. Various mixtures based on PVA (polyvinyl alcohol), montmorillonite modified with hexadecyltrimethylammonium bromide (Mt@HTAB) and graphene were prepared using a solvent mixing process.The flammability properties of these materials were evaluated based on thermogravimetric analysis (TGA) and cone calorimeter tests.The combination of graphene and Mt@HTAB increased thermal stability and reduced flammability (heat release rate (HRR), total heat release rate (THR), and ignition time (TTI)). The ternary mixture has a maximum heat release rate (PHRR) that is 53 % lower than that of pure PVA. The structure of the residues from the cone calorimeter tests was examined using scanning electron microscopy (SEM). This process revealed the presence of compact, dense carbon formed as a result of the combustion of binary and ternary nanocomposites. The ternary mixture has a maximum heat release rate (PHRR) that is 53 % lower than that of pure PVA. The structure of the residues from the cone calorimeter tests was examined using scanning electron microscopy (SEM). This process revealed the presence of compact, dense carbon formed as a result of the combustion of binary and ternary nanocomposites.