The particle size, structure and surface activity of carbon black are important factors in controlling rubber compound properties. In accordance with technical analyses advances, several new parameters are proposed in carbon black characterization. Aggregate size distribution control is an effective measure to adjust the tangent delta (tan δ) of rubber compounds. The hydrogen content (Hc) of carbon black is used for a simplified parameter of surface activity. The amount of Hc is used to quantify reinforcement and electrical conductivity for a rubber compound. AFM analysis is used to explain the carbon black surface nano-structure, and to examine the interaction with rubber molecules. These new parameters are used in combination with conventional characteristics to improve carbon black. Rigorous control of carbon black properties satisfies the customers' demands for diversified rubber products.

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Carbon nanotubes (CNTs) have been drawing much attention as fillers for composites because they have extraordinarily high strength, elastic moduli, flexibility and aspect ratios as well as superior electrical and thermal properties. In this article, author review the studies on composites fabricated with CNTs and resin, metal or elastomer matrices including the latest researches on CNT-filled aluminium composites and elastomer composites. When CNTs were uniformly incorporated in elastomers, isotropic enhancement in their tensile strength and moduli were observed. The flow phenomena at high temperatures disappeared in non-cured rubber matrix composites and thermoplastic elastomer matrix composites with uniform CNT dispersion. These CNT reinforcements are thought to be applicable for producing high efficiency rubber products and their recycling.

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It is demonstrated that the use of silane coupling agents in silica-filled rubber compounds results in a strong increase in reinforcement1). This increase in reinforcement is due to the formation of silica-silane-rubber bonds. The mixing is a key process for the optimized bond formation. Both the silica-rubber coupling and the matrix crosslinking proceeds during the vulcanization of compounds. Therefore, the two crosslinking networks are formed, which cannot be varied independently. In the case of the silica-rubber coupling, this immobilization of rubber on the surface of the silica results in the formation of“in-rubber structure”. In addition to these chemical networks, which result in high moduli at all strains, the physical silica-silica networks also contribute to the modulus at low strains.
The major application of the silica-silane filler system is modern passenger tread compounds for reduced fuel consumption and strongly improved wet traction. Besides tire applications, this unique filler system is also used in various industrial rubber goods. The system will continuously contribute to further improvement in the performance of rubber compounds.

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The author summarizes Synthetic Calcium Carbonate, especially Ultra-fine precipitated calcium carbonate (UF-PCC) and its function as Rubber Additive as follows: within Rubber formulation where Precipitated Silica was applied, the small amount of UF-PCC accelerated integration between Rubber and Precipitated Silica.
Also UF-PCC provided the better properties such as dispersion, tear strength and heat build-up to Rubber Compoundas well.
In the case of Carbon Black applied above formulation instead of Precipitated Silica, UF-PCC reduced BIT in mixing the rubber compound.
We also found that UF-PCC played a role of acid acceptor in the halogenated rubber utilizing UF-PCC and its alkaline property.

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A lot of studies on inorganic-organic complexes have been widely done to develop the materials with new functions. As a result, many inorganic-organic complexes play an important role in several industrial fields. The syntheses of inorganic filler and polymer at the molecular level as nanocomposite have been tried from several years ago. The most suitable inorganic materials with nano-particle size are clay. Montmorillonite, among various clays, acts as nano- filler in polymer because of their high aspect ratio (length: diameter) of about 1000:1. The mechanical and the thermal properties such as strength, modulus, heat resistance, dimensional stability, gas barrier, recyclability of polymer, can be improved by means of dispersion or exfoliation of the layered crystal structure of Montmorillonite to nano-particle size level in the polymer. The exchange of the interlayer inorganic cations such as Na⁺ with organic cations such as alkylammonium cations is required to improve the compatibility of hydrophilic layered crystal of Montmorillonite with polymer matrix.
In this paper, the characters of the layered clay mineral Montmorillonite and its organophilic analogue, organo-Bentonite are reviewed. Preparation, valcanization, and mechanical properties of the rubber/organo-Bentonite nanocomposite are also summarized.

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The surface treatment of the filler with the silane coupling agent (silane agent) is composed of three basic reactins, hydrolysis of silane agent by water, self condensation of silane agent, and the reaction between filler surfaces and silane agent molecules. Because the mechanical properties of elastomer are influenced largely by the filler surface structure formed by silane agent molecules, control of the above mentioned reactions are indispensable to manufacture a elastomer in a constant quality. Effect of the chemical structure of filler surface, adsorbed water on the filler surface and surface treatment condition on these reactions were summarized in this paper. In addition to this, our recent results obtained by atomic force microscope measurement of mica surface, that is, the treatment condition has significant effect on the the structure of the silane agents on the surface of filler, is also introduced.

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The effect of silane coupling agent (CA) as an additive for rubber is of considerable interest because it plays an important role in the silica-filled rubber tires, where both low rolling resistance and wet grip properties are improved. The first silica-filled rubber tire was commercialized in 1991, and bis-triethoxylpropyl tetrasulfide (TESPT) was mainly used. In recent years, bis-3-triethoxysilylpropyldisulfide (TESPD) has been developed since it has higher thereto-stability that makes higher temperature mixing possible. Although the physical properties of the rubber compound containing the later CA is reported to be close to those containing TESPT by controlling the sulfur content, there are some differences in the behavior, and there are many reports to interpret origin of the differences. In this article, relationship between the chemical structure of CA and physical properties of the silica-filled rubber, recent studies on the new type of devlopments are reviewed.

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