The high damping rubber was prepared by the structural modification (isomerization and cyclization, etc.) of natural rubber (NR). The structural modification was carried out by using p-toluenesulfonic acid. The modified NR which generated under reduced pressure has about 2_??_3 times hysteresis loss as compared with that of NR. In the actual compounding, the hysteresis loss of the modified NR increased in 11.5 to 13.4% at third cycle. Also, the Young's modulus was nealy same that of NR, however, the 400% modulus on a large deformation range decreased in 7.3 to 6.8 MPa. By the structural modification, the high damping was simultaneously appeared, while which was kept the low compression set as same as that of NR.

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In this study, Substituent variations Sulfilimines were prepared from sulfides and chloramine T and the delayed action in vulcanization was examined for sulfur cure and peroxide cure. The result showed that as it was already reported the sulfilimine with β-hydrogen(No.5) was effective inhibitor for sulfur cure. And it was proven that the sulfilimine with β-hydrogen (No.5) showed effect as scorch reterder for peroxide cure. This is supposed that the sulfilimine which would prove from the result of PGC-MS decomposes thermally, and olefin is formed. Therefore, it is supposed showing the effect. It seems to be effective for sulfur cure and peroxide cure combined system because the sulfilimine with β-hydrogen has delayed action in vulcanization both sulfur cure and peroxide cure.

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It is known that silica-filled rubbers improve the trade-off between wet traction and the rolling resistance of tires, compared with carbon black-filled rubbers. It is generally considered that the adhesion component of the friction of silica-filled rubbers is higher than that of carbon-filled rubbers, however there are few reports that show this difference in the adhesion components of friction.
In this paper, the adhesion component and the hysteresis component of friction for carbon black-filled and silica-filled rubbers are investigated. Comparing the friction force-frequency curves (F-ω curves) and the viscoelastic properties establishes that the friction force F has the form:
F=As+kE'^-1/3tanδ
where A is the area of contact, s is the shear strength of the rubbers and k is constant. The first term represents the adhesion component of the friction and the second term represents the hysteresis component. It is found that the adhesion component of silica-filled rubbers is higher than that of carbon black-filled rubbers.

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