Epoxy-clay nanocomposites: Influence of the clay surface modification on structure

In this article, the effect of four different clay surface modifiers on the structure of epoxy-clay nanocomposites was studied. Various organoclays were prepared via cation exchange reaction between inorganic cations naturally occuring in the clay gallery and different alkylammonium ions. Epoxy-clay nanocomposites were prepared by in situ intercalative polymerization using a hardener of polyoxypropylenediamine type. It was found that various clay surface modifiers exhibit different catalytic effect on curing of epoxy inside the clay gallery as observed by measuring of the gel time with dynamic mechanical analysis. This was confirmed by monitoring the change in the d-spacing by wide angle X-ray scattering performed in situ during curing. Morphology of the cured systems was probed by transmission electron microscopy (TEM) and wide angle X-ray scattering (WAXS). The degree of dispersion observed by TEM and WAXS corresponds with achieved mechanical properties of cured composites.