| With the rapid development of automobile industry technology and the increasing interests in environmental protection, people make increasingly higher requirements for tire performance. It has become a key issue in the research of high performance tire tread to balance low rolling resistance, high wet traction and high wear resistance. Based on this background, the dissertation mainly focused on the influence of the rubber types, filler kinds, rubber-filler interactions and process conditions on the properties and structures of SSBR/silica composites. The results can provide guidance for the preparation of high performance tire tread.1. Two kinds of domestic solution polymerized styrene-butadiene rubber (SSBR2564S and SSBR2557S) with high vinyl content reinforced by silica were studied, compared with two foreign products (SSBR6270 and SSBR2550). Firstly, the molecular weights and its distributions along with the glass transition temperatures of four SSBRs were studied, and then the cure behaviors, filler dispersion, physical and mechanical properties, wear resistance, compression heat built-up, and dynamic mechanical properties of SSBR/silica composites were analyzed. The results showed that the molecular weights and its distributions of SSBR2564S, SSBR2557S were similar to foreign SSBR2550, while foreign SSBR6270 was coupled, having wider molecular weight distribution. The cure behaviors and scorch safety of all the samples were similar; SSBR6270 showed higher mechanical properties than the others. SSBR2564S, SSBR2557S and SSBR2550 exhibited better wet traction (tan? at 0?) than SSBR6270. Four kinds of SSBRs had good abrasion resistance, low compression heat built-up and low rolling resistance (tan? at 60?), so they can be used or even can be replaced by each other to achieve low rolling resistance as the rubber matrix.2. Five different silicas reinforced solution polymerized butadiene-styrene rubber were compared. Silica types purchased from two famous companies included high dispersive precipitated silicas (165GR,1165MP,7000GR) and conventional precipitated silicas (383, VN3). We observed the surface morphologies using SEM and studied weight losses of those silicas using TGA, and then we focused on the influence of different silicas on the properties of SSBR/silica composites. The results showed that there was no significant difference in the surface morphology of all the silicas; the absorbed water contents on the surface of 7000GR and VN3 were lower than that of 165GR,1165MP,383. Five SSBR/silica composites had similar curing charateristics, and process safety.7000GR had weak Payne effect in the compound, while the other four samples were similar. Five composites had silimar tensile strength; 7000GR showed lower modulus at 300% than the others; 383 had the lowest elongation at break and tensile strength.383 reinforced SSBR composite had the strongest rubber-filler interaction, and 383 provided SSBR/silica composites highest wet traction and lowest rolling resistance, moreover, the other four samples exhibited low rolling resistance, as well.3. Mercapto silane coupling agent Si747 is a new coupling agent, so we mainly investigated the temperature effects on the reactions of silica-silane-rubber via FT-IR, TGA and solid-state 13C NMR. The results showed that Si747 grafting degree on the silica surface increased with elevated temperatures; reaction between Si747 and SSBR occured at 130 ? and in the range of 130? to 160?, the reaction degree gradually increased with enhancing temperature. Moreover, the reaction between Si747 and SSBR was based on the thiol-ene-click reaction, and the vinyl content of SSBR plays an important role.4. The effects of heat treatment temperature on the bound rubber content, filler dispersion, mechanical properties, and viscoelastic properties of SSBR composites filled with silica were investigated. It revealed that bound rubber contents in SSBR/silica compounds with Si747 were much higher, compared with the result of SSBR/silica/TESPT compound in literature. Modulus at 100% and 300%, and the ratio of modulus at 300% to modulus at 100% firstly increased with increasing temperature from 130? to 150?, and then decreased at 160?; the elongation at break of vulcanize showed the maximum at 130? and it reached mimimum at 150?; tensile strength and tear strength showed no significant change with increasing temperature. Moreover, slightly pre-crosslinking between Si747 and SSBR lowered tan8 at 60? of SSBR/silane-silica composites, and a heat treatment temperature of 150? provided SSBR/silane-silica composite with lowest rolling resistance and highest wet grip. |
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