Effect of cationic-surfactant-modified Saudi bentonite on the thermal and flammability properties of poly(vinyl alcohol)-based nanocomposite films

摘要

In this study, poly(vinyl alcohol) (PVA)-modified Saudi bentonite nanocomposite films were preparedusing the solution method. Two surfactants, cetylpyridinium chloride and tetrabutyl phosphoniumbromide, were used to modify the clay after the ion-exchange process by Na+ ions.The effect of the addition of modified Saudi bentonite (2.5%) on the thermal and flammabilityproperties of the nanocomposite films was investigated. The prepared samples were characterizedusing Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electronmicroscopy. Thermogravimetric analysis and differential scanning calorimetry were carried outto observe the thermal behaviour of the PVA-based nanocomposite films. Vertical flammabilitytests (UL94 VB) were also carried out to study the flame retardancy behaviour of the nanocompositefilms. The nanocomposite films showed better flammability than pure PVA, wherein theignition time of the nanocomposites increased and flame propagation rate decreased. The thermalstability of the nanocomposites increased by approximately 10% for the onset and endsettemperature of decomposition. The type of surfactant played an important role in dispersion ofthe clay into the polymeric matrix and enhancing the flammability properties of the films whereinthe tetrabutyl phosphonium bromide was better flame retardant than cetylpyridinium chloride.