Modification of Montmorillonite with Alkyl Silanes and Fluorosurfactant for Clay/fluoroelastomer (FKM) Nanocomposites

Abstract

AbstractThe main objective of the present work was to functionalize nanoclays with organosilanes and surfactant in order to facilitate the dispersion of the nanofillers in the host fluoroelastomer (FKM) polymer matrix. Better dispersion was achieved by improving interaction between the clay polymer nanocomposite (CPN) constituents. The first part of this study investigated modification of montmorillonite (Mnt) using different saturated and unsaturated alkyl silanes and an alkyl hydrocarbon ammonium quaternary surfactant. Silicon magic angle spinning nuclear magnetic resonance spectroscopy, thermal gravimetric analysis (TGA), elemental analysis, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy were used to characterize the silane-grafted clays. Results indicated that the amount of silane grafted depended on the specific structure of the silane. Silane-grafted Mnt was also modified with ionic surfactants intercalated between the clay layers. A 169% increase in the clay basal spacing (from initial spacing of 10.0 Å to 26.9 Å) was achieved. The second part of the study successfully synthesized FKM nanocomposites containing custom-functionalized Mnt, with the aim of producing reinforced high-performance materials. The effects of clay modification on the morphology and thermal properties of the CPN were studied using XRD, TGA, scanning electron microscopy, and transmission electron microscopy. The CPN made with the modified clay exhibited greater thermal stability than the CPN of the commercially available modified Mnt, with a degradation onset point ~ 40°C higher.