Morphology and toughness/stiffness balance of nanocomposites based upon anhydride-cured epoxy resins and layered silicates

Basic correlations between polymer morphology, silicate superstructures, gl ass temperature, stiffness and toughness of thermoset nanocomposites were i nvestigated as a function of layered silicate type and content. The nanocom posites were based upon hexahydrophthalic anhydride-cured bisphenol A digly cidyl ether and layered silicates such as synthetic fluoromica (Fmica), pur ified sodium bentonite and synthetic hectorite, all of which were rendered organophilic by means of ion-exchange with various mono- and difunctional a lkyl ammonium ions. Enhanced toughness was associated with the formation of dispersed anisotropic laminated nanoparticles consisting of intercalated l ayered silicates. Nanocomposite superstructures were imaged by means of tra nsmission electron microscopy (TEM) and atomic force microscopy (AFM).