Effect of mixing conditions and montmorillonite content on the mechanical properties of a chloroprene rubber

Abstract

The effect of organomodified montmorillonite (MMT) content and mixing conditions on the mechanical properties, structure, and morphology of a chloroprene rubber was investigated. Nanoparticles were mechanically mixed with a plasticizer, followed by ultrasonic homogenization before compounding of all ingredients of the mixtures in two-roll mills. Mechanical tests were carried out on samples prepared with three sonication amplitudes and containing different amounts of montmorillonite. The tensile strength and energy to break were found to increase by 15 and 70%, respectively, at the highest nanoclay content but the crack growth rate and tearing energy decreased. Variations in the mixing amplitude and MMT content did not influence the DSC and TGA thermograms, confirming an unchanged thermal stability of the nanocomposites. The highest sonication amplitude led to rubber mixtures with more uniform and homogeneous morphologies, with clay nanoparticles well dispersed and embedded in the rubber matrix.