Acrylonitrile‐butadiene rubber (NBR) nanocomposites with layered silicate (LS), calcium phosphate (CP), and titanium dioxide (TO) of different particle size were prepared in an open two‐roll mixing mill at different filler loading in presence of sulphur as vulcanizing agent. The layered silicate (LS) filled system showed outstanding enhancement in mechanical properties in comparison with nanocalcium phosphate (CP) and titanium dioxide (TO). The variations in properties can be attributed to the extent of intercalation/exfoliation, which was highly influenced by the filler size. The layered silicate filled system at 20 phr showed nearly 349% increase in tensile strength compared to pure NBR whereas an increase of 110% and 84% were shown by CP and TO filled systems respectively. The modulus enhancements were in the order of 200%, 63% and 22%, respectively compared to the unfilled system. The increase in tear resistance was in the order of 230%, 115%, and 41% respectively for the filled systems in comparison with unfilled NBR. The significant enhancements in mechanical properties were supported by the morphological analysis. POLYM. COMPOS., 31:1515–1524, 2010. © 2009 Society of Plastics Engineers

No abstract

The dipping characteristics of prevulcanized natural rubber latex containing three different types of silicates (fluorohectorite, bentonite, and English Indian clay) were studied using a semiautomatic dipping machine. The effect of variation in the speed of immersion and withdrawal of the glass former, dwell time, and concentration of the coagulant, etc. on the thickness of the latex deposit were investigated. Characterization of the composites was done using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The viscosities of these compounds were measured using a Brookfield viscometer. The results of the studies showed that the deposit thickness depends on the withdrawal speed of the glass former, the concentration of the coagulant, dwell time, and the viscosity of the latex compound. Higher film thickness was noticed for the bentonite clay-filled composites. This was believed to be due to the formation of clay network formation in the composites.

The diffusion and transport behavior of nitrile rubber nanocomposites was studied with respect to different types of filler and also different types of solvents. The nitrile rubber nanocomposites showed considerable variations in the molecular transport owing to the tortuosity of path, decreased segmental mobility, and difference in particle geometry. As the matrix under consideration is polar, the behavior of the filled systems in aniline was also studied with a view to understand the polar–polar interaction between the filled matrix and the solvent. The oil repellency as a result of filler addition in the matrix was investigated by studying oil uptake of the nanocomposites. In all these investigations, it has been observed that the filler geometry played an important role in controlling the molecular transport through the polymer matrix. The layered silicate‐filled system showed better solvent resistance and hence minimum solvent uptake in polar and nonpolar solvents and better oil repellency followed by titanium dioxide and calcium phosphate filled systems. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

The viscoelastic properties such as damping behaviour, storage and loss modulus, etc. of polymer composites depend on matrix filler interaction, crystallinity and the extent of crosslinking. It was observed that the storage modulus of the composites increased with the addition of filler due to the enhancement in stiffness of the material. The damping behaviour was found to decrease as a function of filler loading and this was attributed to the restricted movement of the polymer segments. The higher surface area to volume ratio factor of the layered silicate resulted in the better interaction between the polymer matrix and the filler, which resulted in the change in glass transition temperature. The flow properties were studied with special reference to filler loading of different fillers at a specified temperature. It was observed that complex viscosity of filled systems is higher than that of unfilled system. Among the fillers, layered silicate filled systems showed higher viscosity in comparison with calcium phosphate and titanium dioxide fillers.