A Novel Approach towards Highly Exfoliated Natural Rubber-Clay Composites: Preparation and Characterization

The accomplishment of high degree of exfoliation of layered clay minerals in non-polar rubber matrix is a major issue in rubber science and technology. In the present investigation, natural rubber (NR)-organomodified montmorillonite (OMt) nanocomposites with high degree of exfoliation were achieved, utilizing the so called ‘Propping-open approach’, which is a rather simple, straightforward and even industrially viable procedure. Premixing of fatty acids with OMt expanded the interlayer space of the clay mineral layers. This expanded clay mineral was successfully utilized to develop and understand a model truck tire formulation. A synergy in reinforcement between EOMt and CB was attested by the marked enhancement in mechanical properties. A detailed fracture mechanical analysis has also been carried out to understand the effect of expanded clay on the fatigue and fracture behavior of the CB filled NR-clay (filler hybrid) nanocomposites. A significant improvement in crack growth rate was noticed in the presence of only 5 phr of EOMt. We found a beneficial impact of our expanded clay on the tear fatigue properties of the investigated rubber compounds.