Polymer/clay nanocomposites based on MMT/ODA intercalates

Abstract

Natural Na-montmorillonite (MMT) with the formula (Na0.67K0.01Ca0.02)(Al2.90Mg0.59 Fe-0.49(3+) Ti-0.01)(Si7.92Al0.08)O-20(OH)4 was intercalated with octadecylamine (C18H39N) (ODA) with varied MMT/ODA ratios. The basal spacings d(001) of natural and intercalated Na-MMT with ODA were determined by XRD analysis. The set of basal diffractions: d(001) = 56 Angstrom, d(002) = 28 Angstrom, d(003) = 18 Angstrom, d(004) = 14 Angstrom, d(005) = 11 Angstrom for the saturated Na-MMT/ODA intercalate indicates existence of highly ordered periodic structure with the ODA double-layer intercalated in the silicate interlayer spacing. Molecular modeling calculations were applied to the Na-MMT/ODA saturated intercalation system. Stable structure with d-spacing 53 Angstrom has been calculated which is in a good agreement with the experimental data. Such structure gives good conditions for the organosilicate layered structure exfoliation and nanocomposite production. Na-MMT/ODA intercalates were compounded with polypropylene. In accordance with theoretical predictions, XRD analysis applied to compounded structures have proved that a high degree of the organoclay exfoliation was achieved.