Influence of stearic acid treated nano-CaCO₃ on the properties of silicone nanocomposites

The aim of the work reported here was to study the influence of treated nano-CaCO₃ on the silicone:dicumyl peroxide system. Thermal degradation was studied using TGA of treated and untreated nano- and commercial CaCO₃:silicone rubber composites. Thermal stability as well as % char yield increased with increasing content of treated nano-CaCO₃ as compared to untreated and commercial CaCO₃. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed to study the degree of dispersion of treated and untreated nano-CaCO₃ and commercial CaCO₃ in silicone rubber composites. Moreover, the nanocomposites were subjected to various tests, such as those for tensile strength, % elongation at break, flammability and abrasion resistance. The tensile strength (8.5 kg/cm²) and elongation at break (780%) showed their greatest improvements at 10 wt% loading with treated nano-CaCO₃ in comparison to the untreated nano- and commercial CaCO₃:silicone rubber composites. The improvements in the properties of treated CaCO₃:silicone composites compared to the untreated nano- and commercial CaCO₃ silicone rubber composites were due to the uniform dispersion of nanoparticles in the treated composites and their good compatibility with the rubber chains, as shown by AFM and SEM studies.