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.