Multifunctional and specific interactions of CNTs in NBR and HNBR

There are different techniques in practice to disperse multiwalled carbon nanotubes (MWCNTs) in elastomers. In the present work, commercially available MWCNTs NANOCYL NC 7000™ are used as filler. A synthetic Nitrile Butadiene Rubber (NBR) and Hydrogenated Nitrile Butadiene Rubber (HNBR) were used as polymer matrix for the composites prepared by melt blending. The filler dispersion in HNBR was studied through Transmission Electron Microscopy (TEM). The mechanical properties are investigated through strain sweep and tensile tests. Dielectric measurements are carried out to study electrical conductivity of the nanocomposites. Dynamic mechanical measurements showed an enhanced Payne effect and improvement in stiffness with increase in CNTs content into rubber matrix An improvement in electrical and mechanical properties in both NBR and HNBR system resulted by an increase in filler loading. The mechanical and electric percolation threshold of CNTs was found at very low filler volume fraction. Equilibrium swelling experiments were used to study polymer-filler interaction with the help of Kraus plot and diffusion coefficient. NBR showed higher polymer-filler interaction compared to HNBR. In NBR nanocomposites, CNTs showed higher interaction than carbon black. Good dispersion and effective interaction of the CNTs with the polymer led to significant mechanical reinforcing effects.