Preparation and Properties of Nanostructured Rubber-Clay Composites by Two Different Mixing Methods

Based on the unique character of montmorillonite, namely its layer structure and the ability of silicate particles to separate into nanometer size platelets, styrene butadiene rubber (SBR)/clay nanocomposites were prepared by direct latex coagulation and melt intercalation methods. In the former method, SBR/clay nanocomposites were prepared by co-coagulating the mixture of SBR latex and various amounts of Na-MMT aqueous suspension and the latter method is common in rubber industry. In rubber nanocomposites clay dispersion can significantly affect final properties. In order to characterize clay dispersion, X-ray diffraction (XRD) was employed. X-ray diffraction results of nanocomposite up to 5 phr of nanoclay showed the formation of an intercalated structure for melt intercalation method and partial exfoliation for latex method. With ash content test method, distribution of clay in nanocomposites SBR/clay was studied. Studying thermogravimetry analysis (TGA) showed that the main decomposition and end decomposition temperature shift to higher values with increasing MMT loading. Cure characteristics of nanocomposites showed increase in cure and scorch time for latex method and decrease in those in melt intercalation method. With comparing these two methods, one can point to a better dispersion in latex method rather than that in melt mixing method.