Thermoset-layered silicate nanocomposites. quaternary ammonium montmorillonite with primary diamine cured epoxies

The role of various quaternary ammonium-modified montmorillonites in epoxy/diamine nanocomposite formation is examined to further refine the criteria for selection of organic modifiers necessary to enable fabrication of thermoset resins containing nanoscale dispersions of inorganic phases. Utilization of a hydroxyl-substituted quaternary ammonium modifier affords flexibility to combine both catalytic functionality, which increases the intragallery reaction rate, with enhanced miscibility toward both reagents. The rheological implications of these processing techniques are discussed with regards to using thermoset nanocomposites as a matrix in conventional fiber reinforced composites. The use of a low-boiling solvent to enhance mixability and processability of the initial mixtures is shown not to alter the structure or properties of the final nanocomposite. Also, the use of autoclave techniques enabled fabrication of high-quality specimens containing up to 20 wt % organically modified layered silicate (OLS). Finally, exfoliated and partially exfoliated epoxy/diamine nanocomposites were produced with enhanced heat-distortion temperature and increased flammability resistance.