Study of Filler Structure in Silica Filled SBR compounds by means of SAXS and AFM

The structure of silica particles network in two different solution styrene-butadiene rubbers (S-SBR) was studied by means of small angle x-ray scattering (SAXS) and atomic force microscopy (AFM). S-SBR compounds with different silica contents were analyzed in comparison with their oil extended counterparts. A study into the application of Small-Angle X-Ray Scattering experiments was defined in order to quantify the structures of silica primary particles and clusters in filled rubber compounds up to very high levels of filler content. We propose a modified structure model, which is physically sounder than the widely used Beaucage model and leads to more robust quantification of the silica structures. In addition, an independent characterization of the filler structure was performed by means of AFM. The cluster and particle sizes deduced from both techniques are in close agreement supporting the here proposed approach. The synergetic application of SAXS and AFM allows a consistent and robust characterization of primary particles and clusters in terms of size and structure. These results were compared and discussed in the framework of previously published works.