| Recently, with the demand of energy conservation and emission reduction in our country and the increased requirements of security, energy-saving, and comfort for cares, their high-performance tires should have good wet-skid resistance, abrasion resistance and low rolling resistance. However, The three performances are hard to be improved simultaneously, (i.e., one or two properties are improved whereas another two or one property will be decreased), which are often called "magic triangle" in the tire industry. Accordingly, it is a hard problem for the researchers all over the world to develop an ideal tread compound to balance the "magic-triangle" properties. It should have new breakthrough in molecular structure and reinforced structure of rubber. As is well-known to us, the internal friction losses among macromolecular chains and relaxation characteristics are the main factors. Therefore, the design of molecular structure of energy-saving rubber is one of research focuses. Besides, SiO2 is widely used in the tire tread compound for reinforcing function and the significant energy-saving effect and high wet-skid resistance are obtained. However, another problem comes, that is, it is easy to accumulate static. Therefore, how to get better filler dispersion and antistatic property and balance the "magic triangle" properties of the tire tread through molecular structure design, nano-filler reinforcement and adding other conductive fillers is the main research direction of this thesis.In the first part, we mainly studied the structure-property and antistatic characteristics of five kinds of tread compounds, SBR/CB composites. The results showed that the mechanical properties and wet-skid resistance of the four SSBR are similar with those of ESBR, however, the lower heat build-up and rolling resistance are superior to those of ESBR. By comparation of these four kinds of SSBR, the mechanical properties the star-shaped SSBR are excellent, its internal friction loss is the lowest, its wet-skid resistance is high and its rolling resistance is low, followed by SL552,2305 and YL950. Mooney viscosity of YL950 is low, its processing ability is better and vulcanization time is short, with excellent antistatic properties. It indicated that Sn-coupled SSBR have significant energy saving characteristics. In addition, we also studied the structure-property relationship and its antistatic characteristics of oil-extended SSBR with high molecular weight, which exhibited better CB dispersion and lower rolling resistance. The resistivity of all the researched SSBR composites with 50 phr pure CB could meet the antistatic requirements, therefore, the changes of molecular structure parameters and end-modification technologies have less effect on the antistatic property. The conclusions of this part are in favor of selecting novel tire tread compounds and have significance on the subsequent parts.In the second part, we mainly studied the formulations of energy-saving, high-performance and antistatic tread compounds. First of all, we investigated the antistatic characteristics of SSBR with pure CB or SiO2 and the technics of SSBR composites filled with SiO2. It was found that SSBR composites with 50 phr CB exhibited excellent antistatic and mechanical properties, however, the SSBR/SiO2 composites displayed insulation property. Secondly, we studied the structure-property and antistatic characteristics of SSBR YL950 and ESBR 1500 composites filled with different ratios of SiO2/CB. The experimental results showed that CB is 30 nm transparent and spherical particles and form bead-chain network structure. Its Payne effect and dynamic loss are high, and have excellent antistatic property; SiO2 powder exhibited 20-40 nm black and irregular particles, and SSBR/SiO2 composites displayed excellent wet-skid resistance, lower internal friction loss, however, larger static accumulation. SSBR/SiO2/CB composites presented "synergistic effect" effect, especially when the ratio of SiO2/CB is 20/50, the mechanical properties, lower heat build-up, wear resistance, wet-skid resistance and rolling resistance are well balanced, and the antistatic requirement could be met. SiO2/CB (35/35) is the percolation threshold of the composites for antistatic property. Furthermore, when the total amount of fillers is changed, with SiO2/CB in 1/1, the SSBR composites could not meet the antistatic requirements, because of the long distance of fillers or poorer dispersion of the nano-fillers. Then we investigated the CB and ZnO-W effect on the antistatic property, mechanical properties and heat build-up of the SSBR/SiO2/CB composites. It could be found that when the amount of conductive CB was rising, the antistatic property was improved, however, the mechanical properties were decreased, the filler dispersion was poorer and the heat build-up was higher. As for SiO2/CB (40/30), the least amount of the conductive CB is 3 phr in order to meet the antistatic requirement. Nevertheless, ZnO-W was easy to be broken during processing, which went against the formation of conductive networks and presented poor reinforcement. Therefore, the technics should be improved. Moreover, the different storage time of the vulcanizates have less effect on the antistatic property and high aromatic oil could improve the mechanical properties and lower heat generation, however, did harm to the antistatic property. In the third part, we studied the structure-property of end-modified SSBR and its interaction with CB. On one hand, SSBR with tert-Butylchlorodiphenylsilane (TBCSi, large-volume functional groups) at the two ends of macromolecular chains (T-SSBR) were prepared by anionic polymerization. The molecular structure parameters of T-SSBR and SSBR were characterized and the ratio of the amount of macromolecular chain ends connected with TBCSi to total macromolecular chain ends (i.e., end-capping efficiency) was calculated. The results showed that T-SSBR composites presented lower better CB dispersion than those of SSBR composites, which led to decrease in hardness, internal friction, dynamic compression heat built-up and permanent set of T-SSBR composites, significant increase in tensile strength, elongation at break, tear strength and resilience of T-SSBR composites, and excellent balance between wet-skid resistance and rolling resistance. All the above, owing to the end-capping of TBCSi, which could immobilize the free chain ends of T-SSBR (i.e., to reduce the friction loss of molecular chains and create a greater degree of orientation in the force field), and adsorb CB, the comprehensive performances of T-SSBR were better than those of SSBR, therefore the former was suitable for the tread of green tires. On the other hand, we used p-benzoquinone to simulate the transferring of Sn-C bond to CB surface and DSC, FTIR, GPC-UV and 1H NMR technologies were adopted to trace the reaction mechanism of star-shaped PB and p-benzoquinone. It could be found that Sn-C bond of Sn-coupled SSBR is more instable than C-C bond and easy to be broken in 180℃(air) and 198℃(nitrogen). The free radical was produced and caught by p-benzoquinone, and then the molecular chain with benzene-ring structure on the end was formed. Thus the transfer mechanism of Sn-C bond of Sn-coupled SSBR to CB surface and its internal loss essence were achieved. The theoretical principle for the application of end-modification SSBR could be provided.
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