Polystyrene-clay and polystyrene-graphite nanocomposites have been prepared and used to explore the process by which the presence of clay or graphite in a nanocomposite enhances the thermal stability of polymers. This study has been designed to determine if the presence of paramagnetic iron in the matrix can result in radical trapping and thus enhance thermal stability. Nanocomposites were prepared by bulk polymerization using both iron-containing and iron-depleted clays and graphites, and they were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and cone calorimetry. The presence of structural iron, rather than that present as an impurity, significantly increases the onset temperature of thermal degradation in polymer-clay nanocomposites. Intercalated nanocomposites show an iron effect, but this is less important for exfoliated systems. Polymer-graphite nanocomposites show no difference between iron-free and iron-containing nanocomposites, presumably because the iron is not nanodispersed in the graphite.
This paper is NOT THE PUBLISHED VERSION; but the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in th citation below.
This paper is NOT THE PUBLISHED VERSION; but the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in th citation below.
UV-curable polymer films were prepared containing a commercially available, organically modified montmorillonite (MMT). It is believed that nanoclay-containing UV-curable polymers can find wide ranging applications in future microelectronic materials. Polymer films containing the commercially available MMT clay (Nanomer) exhibited enhancements in properties. The polymer films were studied with various microanalytical techniques including XRD, TEM, and SEM to determine their micromorphology. Physical properties and curing kinetics were examined using FTIR and thermal analysis. It was found that the incorporation of clay reduced cure time. Tensile modulus, strength, and glass transition temperature all increased with clay content. Dimensional stability improved with addition of clay. Adhesion between the UV-curable film and polysulfone substrate also dramatically improved. The presence of commercially modified MMT clay, however, rendered the polymers more susceptible to thermal degradation.
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