Optimizing Mechanical and Transport Properties of Carboxylated Nitrile Rubber Composites

The article describes a two-step technique that involves making a masterbatch that is 3:1 [by weight] carboxylated nitrile rubber (XNBR) and nanoclay (NC), compounding on a two-roll mill, and moulding at 150°C and 20 MPa pressure. Tensile strength (TS), elongation at break (EB), and modulus (M100, M200 and M300) all rises with the amount of nanofiller present, peaked at 5 phr, then fell off. The NC demonstrated a tendency to aggregate at greater concentrations. The amount of reinforcement provided by the NC filler can be determined by comparing the modulus of filled compounds (M100_f) to that of unfilled XNBR (M100_u). This ratio rises with the amount of NC present, peaked at 5-7.5 phr, and subsequently fell. Using sorption isotherms, the swelling behaviour of the solvent through the nanocomposites was studied. With increasing NC concentration, the solvent absorption fell, reaching a minimum at 5 phr NC. When toluene sorption for diffusion via XNBR-NC composites was measured, the amount of nanofiller was shown to lower the toluene sorption. Morphological investigation supported the association between the morphology of the nanocomposites and the dependence of different properties on NC content.