Polyimide nanocomposites: Comparison of their properties with precursor polymer nanocomposites

A precursor poly(amic acid) was obtained by solution polymerization of pyromellitic dianhydride and benzidine in N,N-dimethylacetamide. Poly(amic acid)/organoclay hybrids were prepared by the solution intercalation method with dodecylamine-montmorillonite. A polyimide hybrid was obtained from poly(amic acid) hybrid by heat treatment at various temperatures. The film type polyimide hybrids showed better thermal properties than poly(amic acid) hybrids. Also, the thermal stability of the two polymer hybrids were enhanced linearly with increasing clay content from 0 to 8 wt%. Tensile properties and gas barriers of the hybrids, however, were enhanced remarkably compared to pristine polymers. Intercalations of the polymer chains in clay were examined through wide angle X-ray diffraction PM) and electron microscopy (SEM and TEM). Transmission electron microscopy revealed that a partially exfoliated structure had been obtained from polyimide/organo-clay hybrids.