Preparation of natural rubber/ pristine clay nanocomposites by co-coagulating natural rubber latex and clay aqueous suspension

Natural rubber (NR)/ sodium- montmorillonite (Na-MMT) nanocomposites were prepared by cocoagulating NR latex and various amounts of Na-MMT aqueous suspension. Tapping mode AFM and XRD were applied to characterize the microstructure of the nomocomposites. It was observed that fully exfoliated structure could be obtained by this method only when the low loading of layered silicates is used. With increasing Na-MMT content, both non- exfoliated (stacked layers) and exfoliated structures can be observed simultaneously in the nanocomposites. The vulcanized nanocomposites were subjected to the mechanical test. The results showed that nanocomposites present initial moduli and tensile strength greater than NR. Furthermore, initial moduli increased with increasing the Na-MMT loading, indicating the reinforcement effect of Na-MMT on the mechanical properties of NR/ Na-MMT nanocomposites. Compared to the pure NR, the nanocomposite exhibits a higher glass transition temperature and lower tan peak value. TGA results indicated an improvement in main and end decomposition temperature but there is no effect on the suppression of the initial decomposition.