A Quick Method for Assessing the Activity of Shungite Filler in Elastomer Composite Materials

A quick method for assessing elastomer-to-shungite bond strength is presented. An Instron 3365 tensile testing machine was used to measure the force needed to peel away a cotton strip impregnated with a rubber solution in CCl4 from the surface of shungite sheets. The rubbers included butyl rubber (BR), nitrile butadiene rubber (SKN-18), polyisoprene (SKI-3), a copolymer of ethylene and vinyl acetate (CEVA), polychloroprene (PC), chlorosulphonated polyethylene (CSPE), and chlorinated butyl rubber (CBR). The nature of the obtained results depends on elastomer functionality. Smooth curves of the dependence of the measured stress on the distance between the clamps of the tensile testing machine were obtained for elastomers not having functional groups interacting with the shungite, e.g. for BR; on the curves for elastomers interacting with the shungite, e.g. for PC, a series of peaks was observed on the curves. The obtained results make it possible to predict the strength of elastomer composite materials containing shungite.