Epoxy—Vermiculite Nanocomposites as Gas Permeation Barrier

Abstract

Epoxy nanocomposites with organically modified vermiculite were synthesized using a solution casting approach and the microstructure of the composites as well as the gas barrier properties through the cast films were analyzed. Ammonium ions of different chemical architecture were employed in order to analyze the effect on the final composite properties. The modified vermiculite mineral had much higher basal plane spacing than the montmorillonite platelets modified with the same ammonium ions owing to smaller area per cation available on the surface. The basal spacing values were enhanced after nanocomposite synthesis confirming the intergallery polymerization, though a complete exfoliation could not be achieved. Transmission Electron Microscope (TEM) analysis indicated the presence of mixed morphology with tactoids of varying thicknesses present along with a small number of single layers. The permeation properties were significantly improved, even though the pure matrix itself was resistant to oxygen and water vapor permeation. No significant effect of the chemical architecture was observed on the composite properties which were more affected by filler matrix interactions.