Clay modification and its effect on the physical properties of silicone rubber/clay composites

Sodium montmorillonite (MMT) was modified with benzyldimethyltetradecylammonium* chloride (B13) to prepare M‐MMT. Treatment of MMT and M‐MMT with bis(3‐triethoxy silylpropyl) tetra sulfide (TEPTS) introduced tetra sulfide groups (TS) on the surface of the clays and yielded MMT‐TS and M‐MMT‐TS, respectively. A high temperature vulcanization silicone rubber (HTV) was compounded with MMT, MMT‐TS, M‐MMT, and M‐MMT‐TS, and the morphology of the resulting HTV/clay composites was analyzed by using the corresponding TEM images. The degree of swelling of the HTV composites in the toluene solution was measured to gauge their crosslinking density and thus to exclude the possibility that the enhanced mechanical properties came from increase in the crosslinking density. The greatly improved mechanical properties, as a result of the incorporation of the TEPTS‐modified clay into HTV, were attributed to the enhanced interaction owing to the plausible chemical reaction between the TEPTS‐modified clay and the HTV matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012