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The effects of bound rubber on vulcanization kinetics were studied on poly(methyl vinyl) silicone rubber (VMQ) filled with three different types of silica, which was surrounded by different amount of bound rubber due to their morphological differences. Higher specific surface area (SSA) and content of silica corresponds to the more favorable formation of bound rubber. The results of cure kinetic behavior demonstrate that the loading of silica suppresses the vulcanization rate compared to neat rubber. Under the same filler content, the higher the bound rubber content, the more obvious the inhibitory effect on vulcanization reaction. A structure model of filler network mediated by bound rubber was proposed to account for the influence of the reinforcing particles on vulcanization kinetics and rheological behavior of silicone rubber, which may be adopted to analyze the properties of nanocomposites with different fillers.

For a better understanding of the influence of the immobilized rubber on the non-linear viscoelasticity of filled rubber, spherical silica without intensive filler–filler interactions and with weak silica–rubber interactions was introduced in order to compare the non-linear viscoelasticity of the commercial silica filled rubber. It was observed that the amplitude of Payne effect is related to the interfacial interaction characterized by the content of bound rubber. An interesting phenomenon was produced in the effect of temperature on the Payne effect for spherical silica filled rubber that the amplitude of Payne effect decreases with the temperature below 253 K but the storage modulus increases with the temperature above 253 K which performs the feature of entropic elasticity as pure rubber. The activation energy of the unstable chains can be also divided into two sections in the temperature range which is related to the critical value of immobilized rubber to influence the Payne effect. The results reveal that the number of immobilized rubber reduces with the temperature and it has a critical value to affect the Payne effect which is verified by Maier–Goritz model. The introduction of this kind of spherical silica provides an experimental method to study the non-linear viscoelasticity elaborately.