Morphology and structure of silica agglomerates in silica‐reinforced silicone rubber

Light‐scattering and optical microscope observations of silica‐reinforced silicone rubber have shown that the filler is dispersed in a complex manner. Much of the original material appears agglomerated into particles several microns in size. These particles apparently further cluster to form agglomerates of about 20 μ in diameter. In an earlier paper in this series it was shown that the thermodynamic function fe/f (the fraction of the retractive force due to internal energy changes) was a measure of the reinforcement level. It is now proposed that the corresponding physical mechanism of reinforcement may have its origin in the large amounts of energy required to deform the filler particle agglomerates.