Entrapped Styrene Butadiene Polymer Chains by Sol–Gel-Derived Silica Nanoparticles with Hierarchical Raspberry Structures

A sol-gel transformation of liquid silica precursor to solid silica particles was carried out in a one pot synthesis way where a solution of styrene butadiene elastomer (S-SBR) was present. The composites, thus produced, offered remarkable improvements of mechanical and dynamic mechanical performances as compared with precipitated silica. The morphological analysis reveals that the alkoxy-based silica particles resemble a raspberry structure when the synthesis of the silica was carried out in presence of polymer molecules and represent a much more open silica-network structure. However, in absence of polymer the morphology of the silica particles is found to be different. It is envisaged that the special morphology of the in-situ synthesized silica particles contributes to the superior reinforcement effects which are associated with a strong silica-rubber interaction by rubber chains trapped inside the raspberry-like silica aggregates. Therefore, the interfaces are characterized in detail by low-field sol...