Characterization of the incorporation of a granular medium into elastomer matrices during mixing process

Mixing of filler particles with elastomers is one of the most important steps in tire manufacturing process. Precipitated Silica (Si), as a filler, shows enhanced properties compared with carbon black when incorporated with an elastomer such as low rolling resistance, high wet grip performance, and high wear resistance. According to the standard rubber mixing process, the fragmentation of the filler particles in an elastomer during mixing must yield to breakage of particles to a size that enables homogenous mixing of the material. Hence, this experimental study is concerned with understanding the behavior of silica during its incorporation in the elastomer. Incorporation is done through shear forces present in the Internal Mixer. Different experimental methodologies are used to measure the particle size distribution. For free silica particles that have been fragmented but not incorporated, we use Laser granulometry. Silica embedded in elastomer is analyzed using X-ray tomography. The results obtained suggest that free silica and silica embedded in elastomer follow erosion mechanism.