The study on dispersion of filler in rubber/filler system by ASAXS

In rubber/filler system, the dispersion of the filler greatly affects the mechanical properties. Zinc oxide (ZnO) plays an important role in the cross-linking reaction as a vulcanization accelerator, but also affects the dispersion of the filler, so the dispersion of ZnO is also important. In order to investigate the nm order dispersion of filler and ZnO, small angle X-ray scattering (SAXS) is a powerful technique. However, it is difficult to clarify the respective dispersion because the sizes of the dispersion of CB and ZnO are close. To solve this problem, we focused on anomalous small angle X-ray scattering (ASAXS). ASAXS is a technique for performing SAXS measurements with different contrasts by varying the incident X-ray energy near the element-specific X-ray absorption edge. Using this method, the partial scattering function of CB and ZnO in Ethylene Propylene Diene Methylene Linkage(EPDM)/CB/ZnO were obtained. In order to quantitatively estimate the dispersion of the CB, the partial scattering function of CB was fitted using the Unified Guinier/Power-Law Approach. As a result, it was found that the mass fractal dimensions of aggregates of CB differed depending on the kneading process. In addition, the distribution of ZnO changed with the kneading process.