Morphology and rheology of (styrene-butadiene rubber/acrylonitrile-butadiene rubber) blends filled with organoclay: The effect of nanoparticle localization

Abstract

In this study, immiscible acrylonitrile butadiene rubber/styrene butadiene rubber (NBR/SBR) blends and their nanocomposites with cloisite 15A (C15A) and cloisite 30B (C30B) nanoparticles were prepared via a melt mixing method. The structure and morphology of the prepared samples were investigated by theoretical methods and by using equipment including X-Ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The experimental results proved that the C30B, the more hydrophilic organoclay (OC) tended to confine in the NBR, the more polar rubber phase, and in the interface whereas C15A, the less hydrophilic one was located at the SBR and interface. This was in agreement with the results obtained by the calculation of the wetting parameter. The EDS results showed that the average area of the NBR droplets in the SBR/NBR (80/20) blend decreased from 1.13 to 0.8 and 0.76μm2 in the presence of C30B and C15A, respectively. The use of epoxidized natural rubber (ENR) in conjunction with the OC caused more reduction of the NBR droplet size. Rheo-mechanical spectroscopy displayed the significant effect of OC localization on viscoelastic properties of the blends. Meanwhile, the rheological behavior of the blends was quantitatively similar to that predicted by Palierne's model extended to filled immiscible blends. This model was applied to obtain morphological and interfacial information for the SBR/NBR nanocomposite.