Organic montmorillonite as a substitute for aerosilica in addition-type liquid silicone rubber systems

A novel addition-type liquid silicone rubber (SR)/organic montmorillonite (OMMT) nanocomposite has been synthesized. N,N-Di(2-hydroxyethyl)-N-dodecyl-N-methylammonium chloride was used as an intercalation agent to treat Na+-montmorillonite and form a novel kind of OMMT. Three types of SR/OMMT composites were synthesized with different amounts of OMMT, and were compared with an aerosilica-modified SR system. Tensile strength, and other properties determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), were compared. A combination of Fourier-transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electronic microscopy (TEM) studies showed that SR/OMMT composites were on the nanometer scale, and the segmented structure of the SR was disrupted by the presence of OMMT, as a result of the reaction between the monomer and the intercalation agent. Results showed that the physical and mechanical properties of an SR system with 1 phr of OMMT were nearly equal to that of an SR system with 3 phr of aerosilica because of the exfoliation of the OMMT and the resultant nano-effect in the system.