Barrier properties of polypropylene/organoclay nanocomposites

Polypropylene/clay nanocomposites are attractive candidates for applications requiring good barrier properties because of the inherent features of the polymer matrix. To assess their potential, systematic research relating the barrier performance to the structural characteristics of polypropylene/montmorillonite samples has been conducted. The nanocomposites have been tested in the presence of helium, water vapor, toluene, and methanol, and the unmodified matrix has been found to exhibit better properties than its mixtures with the compatibilizer and/or clay. The method for the interpretation of the results proposed in this study considers the composition of the samples, the morphology of the semicrystalline polymer matrix, and the state of dispersion/exfoliation of the clay layers, along with the specific interactions between the solvent molecules and the system components. In this way, several points have been identified for understanding and improving the performance of the nanocomposites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 618–625, 2007