Effects of Epoxidized Natural Rubber on Gas Barrier and Mechanical Properties of NR/BIIR Composites

The mechanical properties and gas permeability of natural rubber/bromobutyl rubber blends were investigated when using epoxidized natural rubber (ENR) as a compatibilizer. The blend composites used in this study were composites of commercial precipitated silica. Several types of layered silicates were investigated here as secondary fillers due to their high-aspect ratio platelet structures, which could help delaying the gas permeation rate. These fillers include talcum, montmorillonite clay, and kaolinite clay. We found that, ENR could promote faster cure and could improve the mechanical properties, compression set, and abrasion resistance of the composites with significant improvement in its gas barrier property. Among different types of fillers, talcum could provide superior gas barrier property to other types of fillers, even though the strength and modulus of talcum composite were still inferior to those of other composites. However, the addition of ENR to talcum composite did not further improve its gas barrier property further, though it could improve the other properties.