Novel nanocomposites based on chlorinated styrene butadiene rubber and manganous tungstate: focus on curing, mechanical, electrical and solvent transport properties

The present work investigates the influence of loading of manganous tungstate (MnWO₄) nanoparticles on the rheometric processing characteristics, crystallinity, morphology, glass transition temperature, oil resistance, transport behavior, mechanical and electrical properties of chlorinated styrene butadiene rubber (Cl-SBR). The reduction in the overall amorphous nature of Cl-SBR has been observed with the addition of nanofillers, as confirmed by X-ray diffraction studies. The maximum uniform dispersion of nanofiller in Cl-SBR has been noted at 7-phr loading, while at higher loadings, filler agglomerations have been observed in the scanning electron micrographs. An increase in the glass transition values with the addition of nanoparticles proves the reduced flexibility of the elastomer systems. The reduction in optimum cure time with the loading of nanoparticles has been found to be beneficial as far as the production rate of articles using these nanocomposites is concerned. Among the mechanical properties studies, tensile strength, modulus and tear strength registered an increase in the loading of nanofillers up to 7 phr due to the reinforcement of elastomer by the nanoparticles. The AC conductivity of Cl-SBR/MnWO₄ nanocomposite increased with increasing the frequency and loading of nanoparticles. It is important that at 7-phr loading of nanoparticles, the conductivity value reaches the range of semiconductors. The superior reinforcement of Cl-SBR with 7-phr nanoparticles has been supported by the results of solvent diffusion and transport studies also. Values of solvent sorption parameters such as the energy of activation and enthalpy of diffusion have been found to be complementary to each other supporting the results obtained earlier. The reinforcing ability of the nanoparticles in Cl-SBR has been correlated with Lorentz and Park model.