Study on volume change and scanning electron microscopy observation of silica-filled solution polymerized...

Solution polymerized styrene-butadiene rubber/cis-1,4-polybutadiene rubber (SBR/BR) blends filled with silica is widely used system in tread compounds for passenger tires. The application of silane coupling agents greatly improves the interaction between polymer and filler through chemical bonds. By testing a series of SBR/BR blends filled with different specific surface area and content of silica, we measured the volume change data of the compounds upon stretching and plotted the corresponding ΔV/V-ε curves. In order to normalize for stress differences, ΔV/(Vσ)-ε curves were also plotted using stress-strain data. Scanning electron microscopy (SEM) was used to observe the microstructures in the vulcanizate in situ when stretched. The dispersion, agglomeration, and vacuole formation process can be visualized clearly in the SEM images.