Effect of bonding agents on natural rubber-aluminium powder composites

The effects of various bonding agents, namely the hexamethylene tetramine-resorcinol system (HR), bis[3-(triethoxysilyl)propyl]tetrasulphide (Si-69), cobalt naphthenate (CoN), and toluene diisocyanate (TDI), on the mechanical properties of aluminium powder-filled natural rubber composites have been investigated. Studies were done both as a function of the bonding agent by keeping the loading of aluminium powder constant and as a function of the aluminium powder loading along with the bonding agents. Shore A hardness, rebound resilience, heat build-up, etc., are increased by the use of bonding agents, due to the improved adhesion between the natural rubber and aluminium powder. The addition of a bonding agent minimizes the DIN abrasion loss and percentage of compression set. The tensile properties can also be improved by adding bonding agents. Of the various bonding agents used in this study, the silane coupling agent (Si-69) and the hexamethylene tetramine-resorcinol (HR) system were found to be better for natural rubber-aluminium powder composites.