Characterizations of UV-Curable Montmorillonite/Epoxy Nanocomposites Prepared by a Hybrid of Chemical Dispersion and Planetary Mechanical Milling Process

Abstract

Ammonium salt, [2-(methacyloyloxy)ethyl] trimethylammonium methyl sulfate (MAOTMA), was adopted to modify montmorillonite (MMT) via the cationic exchange process in an acidic environment and a successful enlargement of MMT lamellar spacing from 1.18 to 1.39 nm was identified by x-ray diffraction and Fourier-transform infrared spectroscopy. Accordingly, UV-curable epoxy nanocomposite resins containing various amounts of MAOTMA-modified MMT were prepared with the aid of a planetary mechanical milling process. Transmission electron microscopy revealed a uniform dispersion of exfoliated MMT lamella in epoxy matrix, leading to the distinct improvements on thermal stability and thermal expansion property of nanocomposite samples. Calcium (Ca) test indicated that the good dispersion of MMT fillers in polymer effectively suppresses the moisture permeation in sample matrix. More than twofold increment on retention time of 5% Ca hydrolysis and 20% improvement on the permeation kinetic parameters were observed in the nanocomposite sample containing 8 wt % MMT in comparison with the pristine epoxy sample. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3199-3207, 2012