Nanocomposites were prepared with different grades of nitrile rubber with acrylonitrile contents of 19, 34, and 50%, with styrene–butadiene rubber (23% styrene content), and with polybutadiene rubber with Na‐montmorillonite clay. The clay was modified with stearyl amine and was characterized by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The XRD studies showed an increase in the gallery gap upon the modification of the filler by stearyl amine. The intercalation of the amine chains into the clay gallery gap was confirmed by the presence of some extra peaks (2928, 2846, and 1553 cm−1) in the FTIR spectra. The clay–rubber nanocomposites were characterized by TEM and XRD. The mechanical properties were studied for all the compositions. An improvement in the mechanical properties with the degree of filler loading up to a certain level was observed. The changes in the mechanical properties, with changes in the nature and polarity of the rubbers, were explained with the help of XRD and TEM results. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1573–1585, 2004

Rubber-based nanocomposites were prepared with octadecyl amine modified sodium montmorillonite clay and styrene-butadiene rubber with different styrene contents (15, 23, and 40%). The solvent used to prepare the nanocomposites, the cure conditions, and the cure system were also varied to determine their effect on the properties of the nanocomposites. All the composites were characterized with X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The XRD studies revealed exfoliation for the modified clay-rubber composites. The TEM photomicrographs showed a uniform distribution of the modified clay in the rubber matrix. The thickness of the particles in the exfoliated composites was around 10 -15 nm. Although the FTIR study of the unmodified and modified clays showed extra peaks due to the intercalation of the amine chains into the gallery, the spectra for the rubber-clay nanocomposites were almost the same because of the presence of a very small amount of clay in the rubber matrix. All the modified clayrubber nanocomposites displayed improved mechanical strength. The styrene content of the rubber had a pronounced effect on the properties of the nanocomposites. With increasing styrene content, the improvement in the properties was greater. Dicumyl peroxide and sulfur cure systems displayed similar strength, but higher elongation and slightly lower modulus values were obtained with the sulfur cure system. The curing of the samples at four different durations at 160°C showed that the cure time affected the properties.

Polymer nanocomposite is one of the highly discussed research topics in recent time. In this paper, we have reported the preparation and the properties of different nanoclays based on sodium montmorillonite, bentonite and potassium montmorillonite and organic amines of varying chain lengths, and Styrene Butadiene Rubber (SBR)-clay nanocomposites. The clays and the rubber nanocomposites have been characterized with the help of Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). X-ray results suggest that the intergallery distance is increased by incorporation of various amines. There is a great improvement in mechanical properties like tensile strength, elongation at break, modulus, work to break, and hysteresis on incorporation of nanoclay in SBR. TEM photographs show exfoliation of the clays in rubber to 5–10 nm range. The X-ray diffraction peak observed in the range of 3°– 10° for the control and the modified clays also disappears in rubber nanocomposites. Increasing chain length of clay modifiers and loading and nature of clays affect the mechanical and thermal properties significantly.

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In this work, preparation and properties of different nanoclays modified by organic amines (octadecyl amine, a primary amine, and hexadecyltrimethylammonium bromide, a tertiary amine) and brominated polyisobutylene-co-paramethylstyrene (BIMS)-clay nanocomposites are reported. The clays and the rubber nanocomposites have been characterized with the help of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The X-ray diffraction peaks observed in the range of 3°-10°for the modified clays disappear in the rubber nanocomposites. TEM photographs show predominantly exfoliation of the clays in the range of 12 Ϯ 4 nm in the BIMS. In the FTIR spectra of the nanocomposites, there are common peaks of virgin rubber as well as those of the clays. Excellent improvement in mechanical properties like tensile strength, elongation at break, and modulus is observed on incorporation of the nanoclays in the BIMS. Structure-property correlation in the above nanocomposites is attempted.