Effect of clay type on structure and properties of poly(methyl methacrylate)/clay nanocomposites

PMMA nanocomposites using natural Cloisite 6A and synthetic Lucentite SPN clays were produced via melt blending. The degree of intercalation or exfoliation was measured for both composites using transmission electron microscopy (TEM) and the results were confirmed with small angle X-ray scattering (SAXS). The smaller dimensions of the synthetic SPN, as well as the complete absence of Pe ion impurities allowed for the production of a composite which was optically clear and completely colorless. TEM and SAXS measurements were performed on samples heated to high temperatures. The data showed that in both cases large ribbons composed of the individual platelets were formed. We postulated that these ribbons formed a barrier against spreading of the flame and hence the smaller clays, which are more mobile, had a higher efficiency.