Influence of organically modified clays on the barrier properties of bromo butyl rubber composites for tyre inner liner application

The barrier and mechanical properties are the primary requirement of a rubber for tyre inner liner application that can be fulfilled by incorporation of organically modified clay (OMC) into rubber matrix. In this work, functional rubber composites with an improved gas barrier performance were prepared using bromobutyl rubber (BIIR) and natural rubber (NR) as the elastomer phases, and OMC and carbon black (CB) as the functional fillers by employing standard solid-state mixing and vulcanization methods. CB was partially replaced by OMC to achieve adequate barrier and mechanical properties. OMC modified composite showed ~35% improvement in the barrier properties as compared to the control compound (60 phr carbon black, 10 phr NR and 90 phr of BIIR loaded rubber compound). The dispersion of the nano clays were investigated by transmission electron microscopic (TEM), scanning electron microscopic (SEM) and X-ray diffraction (XRD) studies. The XRD study revealed that higher d- spacing and crystalinity of the nano clay composites ease the exfoliation tendency. The mechanical properties of the clay filled nano composites, such as hardness tensile strength, modulus and air barrier properties were superior to the control compound. The developed BIIR/nanoclay composites with improved barrier properties prepared by conventional mixing method in line with common industrial practice can be used in rubber products such as tire inner liner.