Also, a type of sulfidic linkage of the cross-linked composites is focused in this study and was investigated by using synchrotron X-ray absorption near-edge structure (XANES) spectroscopy. Generally, the type of sulfidic linkage of the rubber products is well known to affect their physical properties. Therefore, it must be useful to study the effect of cross-linking sulfides as well as that of in situ silica on the sulfur cross-linked composite. Significant progress of sulfur K-shell XANES spectroscopy has been made over the last several years[17-19] and there are numerous XANES studies to clarify local geometric and electronic environment of sulfur atoms in sulfur materials.[20-30] Also, several studies have been reported on NR vulcanizates[27-29] and styrene-butadiene rubber vulcanizates.[30] These results have been used to identify the characteristics of the cross-linked NR composites in this study. Transmission electron microscopy (TEM) and dynamic mechanical analysis (DMA) are also conducted to investigate the morphology and dynamic mechanical properties of new soft composites, respectively.