Polyimide/silica hybrid-clay nanocomposites

A hybrid-clay nanocomposite was prepared by dispersing organically modified layered silicates (organoclay) into an organic-inorganic hybrid matrix. Layered silicates were dispersed in a hybrid matrix consisting of an alkoxysilane terminated amide acid oligomer and tetraethoxysilane. Transmission electron microscopy (TEM) and wide angle X-ray diffraction (WXRD) confirmed uniform dispersion and a high degree of predominantly exfoliated layered silicates. Storage modulus of the hybrid film containing 5 wt% exfoliated clay was 300% higher above the glass transition temperature and 30% higher at room temperature. The room temperature tensile strength and elongation to break decreased moderately with increasing clay loading. This approach provided a means of achieving excellent dispersion of predominantly exfoliated clay by reacting hydroxyl groups in the inorganic and organic precursors with hydroxyl groups at the edges of the clay layers. (c) 2005 Elsevier Ltd. All rights reserved.