INVESTIGATION OF THE RUBBER-METAL BONDING SYSTEM BY MEANS OF ANALYTICAL ELECTRON-MICROSCOPY AND COMPARISON WITH RESULTS OF TECHNICAL TEAR STRENGTH MEASUREMENTS

During vulcanization of sulfur-cure mixtures in contact with brass, a bonding layer consisting of sublayers of copper and zinc sulfides and oxides is formed. As the chemical composition and structure of the lay er are decisive for good adhesion, the rubber to brass bonding was inv estigated using an analytical electron microscope (AEM) coupled with a n energy dispersive X-ray (EDX) detector. Sublayers were found in the bonding layer between rubber and brass. Different crystallographic pha ses were identified in an etched bonding layer by electron diffraction . Technical tear strength measurements were carried out using rubber-b rass-rubber samples, showing correlations with the electron microscopi c investigations. This method is a new approach to the rubber-metal bo nding (adhesion) problem.