2.5.4. Morphology examination
The morphology of silica in both uncompounded and
vulcanized samples was examined by using a scanning
electron microscope (model S-2500, Hitachi) at an accelerating
voltage of 15 kV and vacuum atmosphere. Newly
cryogenically fractured surfaces of the rubber specimens
were prepared before coating with Pt–Pd to prevent the
charging on the surface.