Effect of the Silicon-Containing Phase on the Hierarchy of the Structure of Epoxy-Silica Nanocomposites

Structural features of epoxy-silica nanocomposites obtained by cationic polymerization were studied by small-angle X-ray scattering. An increase in the amount of the inorganic phase in this system leads to greater aggregation of the silica particles. The structure of such systems is described satisfactorily be a model with multilevel fractal aggregation. Fractal analysis was used to identify the type of fractal aggregates of each structural level and to determine their dimensions. Aggregates with mean radius 10-13 nm are formed at the first structural level, while silica particles form aggregates with mean radius 55-67 nm at the second level. The mean radius of aggregates at the third level exceeds 250 nm.