Tires Black rubber formulations

Tire tread rubber formulations were prepared by Parker [4] and consisted of poly(styrene-co-butadiene) rubber terminated with iV-isopropylphenylnitrone, (III), to promote interaction between the polymer end-groups and carbon black and silica fillers to reduce hysteresis. 

A typical tire rubber formulation for tire tread will contain various rubbers, mainly styrene-butadiene (50%) and cA-polybutadiene (12%), various processing aids (2%), softeners (3%), vulcanizing agent (mainly sulfur 1%), accelerators, and reinforcing filler (namely carbon black 30%) so that by bulk, carbon black is the second most used material. 

Ultraviolet light initiates free radical oxidation at the exposed surface of an elastomeric product to generate a layer of oxidized rubber. Heat, moisture, or high humidity can then initiate crazing of the surface, which subsequently can be abraded off. Such degradation of the surface is more severe with nonblack stocks than with black compounds. Nonblack compounds such as white tire sidewalls thus require higher levels of nonstaining antioxidants than carbon black-loaded formulations. 

Extensive fiirther work was needed to develop synthetic tire rubber from mixtures of mono- and di- ethenes but the empirical nature of the work toward a fimctional tire is well illustrated by efforts to understand the reinforcemerrt of the total rubber formulation by various grades of carbon black. 

This scries of robbers includes monomer ratios up to about 50% styrene. The addition of more than 50% styrene makes the materials more like plastic than robber. The most commonly used SBR rubbers contain about 25% styrene, which is polymerized in emulsion systems at 5-l0°C. Most SBR goes into tires, but the type for the tread differs from that of the sidewall or carcass. SBRs for adhesives, shoe soles, and other products also differ. The formulation permits vast varieties of end products. Among the processing variables that can be manipulated tu provide different end characteristics are temperature, viscusily. use of different emulsifiers and solvents, use of different antioxidants for stabilization, different oils, carbon blacks, and coagulation techniques. 

Antioxidant for natural and synthetic rubber, tires, automotive and appliance molded goods, polyamides and carbon black filled olefin formulations for use in geomembranes, wire and cable jacketing, and irrigation piping. 

In most tire formulations, sulfur plus an accelerator forms the vulcanizing system. The rubber is reinforced with carbon black, and a number of other specialized ingredients are added, as shown in Table Although... 

Where great mechanical strength is not required, and thus carbon black not used, rubbers can be colored with pigments, just as plastics. A typical radial passenger-tire tread formulation is shown in Table 19.1. Notice that the additives (everything except SBR polymer and cw-polybutadiene) make up 122.25 parts per hundred parts polymer or more than half of the tire ... 

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