Preparation and Evaluation of the Microstructure and Properties of Natural Rubber/Sodiummontmorillonite Nanocomposites

Natural rubber (NR)/sodium-montmorillonite (Na-MMT) nanocomposites were prepared by co-coagulating the mixture of NR latex and various amounts of NaMMT aqueous suspension. Tapping mode AFM (for the first time in the present case) , TEM and XRD were applied to characterize the structure of nanocomposites. Results showed that at the low loading of layered silicates , fully exfoliated structure could be achieved by this method . Both non-exfoliated (stacked layers) and exfoliated structures were observed in the nanocomposites when the amount of Na-MMT increased to 10 phr. The mechanical results on the vulcanized nanocomposites showed that nanocomposites present initial moduli and tensile strength greater than Na-MMTfree NR compound. Furthermore, initial moduli increased with increasing the Na-MMT loading, indicating the reinforcement effect of Na-MMT on the mechanical properties of nanocomposites. The nanocomposites exhibit a higher glass transition temperature and lower tangent peak value in comparison with Na-MMT-free NR compound . TGA results indicated an improvement in the main and end decomposition temperature but there is no effect on the suppression of the initial decomposition temperature.