Physical properties and morphology of a series of hydrogenated polystyrene-block-poly (styrene-co-butadiene) -block-polystyrene (SSEBS) were investigated using tensile test, transmission electron microscope and pulse NMR. Physical properties and miscibility of the blends of SSEBS with isotactic polypropylene (PP) also were investigated using the same methods. These SSEBS were prepared by hydrogenation of anionically polymerized polystyrene-block -poly (styrene-co-butadiene)-block-polystyrene (S-SB-S). The content of styrene in the SB block was varied from 0 to 25% in order to examine effects of styrene content. The total styrene contents of two end polystyrene blocks were about 15%. Tensile strengths and scratch hunting resistance of the blends of those S-SEB-Ss with PP increased with increase in styrene content of SEB block. However, the miscibility of the blends slightly decreased with increase in the styrene content.

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Weak-interaction system takes change toward homogenization due to the principle of increase of entropy. In some cases, however, nature likes inhomogeneity. An example can be found in the great wall in universe. Recently, several studies on rubber materials are in progress from such the viewpoint. Some of them are introduced in this article.

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Usual rubber products are a composite from rubber and nano-filler (e.g. carbon black, silica, etc.), and it is believed that the good dispersion of the nano-filler is the most important issue determining the performance of rubber vulcanizates. So far, transmission electron microscopy (TEM) has been the most useful tool for evaluation of the dispersion. However, it affords images of the sample projected on an x, y-plane, and the information along the thickness (z-axis) direction is missing. Three-dimensional (3D) visualization of nanometer structure of nano-filler dispersion in a rubber matrix is what all rubber technologists have been dreaming of. This dream is at last realized, and described in this paper. Use of electron tomography combined with TEM (3D-TEM) enabled us to reconstruct 3D images of nano-filler aggregates in rubbery matrix. The 3D-TEM results on carbon black and silica in natural rubber were presented. Electrical resistivity of carbon black loaded natural rubber, as an example of physical properties, was measured, and explained by the structure elucidated by 3D-TEM. This technique will prove to be more and more important for the rational design of the nano-composites of rubbery matrix.

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This paper referred to the effects of silica and the water content included in the compounds on the vulcanization of silica loaded compounds. The vulcanization became slower with the loading of silica, but faster with increase of water content in the compounds. It was considered that the disturbance of vulcanization with silica was due to the acidity of silanol groups, and acceleration of the reaction between zinc oxide and stearic acid with water was responsible for the acceleration of the vulcanization.

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