Gradute School of Frontier Sciences, The University of Tokyo, Japan^* SRI R&D ltd., Japan^**
○Yuya Shinohara^* Hiroyuki Kishimoto^** Yoshiyuki Amemiya^*

Carbon black and silica particles are widely used as filler to reinforce rubber. The mechanism of reinforcement, however, has not been clarified yet. The aggregation structure of filler is supposed to be one of the origins of the reinforcement, and now attracts much attention in rubber science. In order to elucidate the role of filler in the reinforcement, it is important to clarify (1) the structure of filler aggregates and (2) their dynamics in rubber. Two-dimensional ultra-small-angle X-ray scattering (2D-USAXS) and X-ray photon correlation spectroscopy (XPCS) are promising tools to investigate filler aggregate structure and filler dynamics, respectively. Filler aggregates show hierarchical anisotropic structure on the order of 0.1 - 10 μm. Conventional scanning-USAXS using Bonse-Hart camera is not appropriate to study the anisotropic structure. Recently, we have developed time-resolved 2D-USAXS at BL20XU, SPring-8 and have investigated the deformation process of aggregated filler in stretched rubber by 2D-USAXS. Also, we have investigated the dependence of the filler dynamics in rubber on temperature, the volume fraction of filler, vulcanization, and the size by XPCS. In this talk, we describe 2D-USAXS and XPCS of rubber filled with silica particles and show their potential for structural analysis.