XRD Study of Intercalation in Statically Annealed Composites of Ethylene Copolymers and Organically Modified Montmorillonites. 1. Two-tailed Organoclays

TLDR: In this paper, the effect of the preparation conditions has also been addressed through the characterization of selected samples with similar composition prepared by melt compounding or solution blending, and the results show that intercalation of the copolymer chains occurs rapidly within the galleries of most of the investigated organoclays, independent of whether shear stress is applied to the molten mixtures.

Abstract: Ethylene copolymers with different polar comonomers, such as vinyl acetate, methyl acrylate, glycidyl methacrylate, and maleic anhydride, have been used to prepare polymer/clay nanocomposites by static annealing of their mechanical mixtures with different organoclays containing two long alkyl tails. The nanostructure of the products and the dispersion of the silicate particles have been monitored by X-ray diffraction and microscopic analyses. The effect of the preparation conditions has also been addressed through the characterization of selected samples with similar composition prepared by melt compounding or solution blending. The results show that intercalation of the copolymer chains occurs rapidly within the galleries of most of the investigated organoclays, independent of whether shear stress is applied to the molten mixtures. Solution blending, though leading to effective and uniform dispersion of clay primary particles within the polymer bulk, resulted unable, without subsequent thermal treatments, to lead to intercalation. However, the micron-sized polymer/clay mixtures prepared from solution change even more rapidly into intercalated nanocomposites upon static melting. Most of the polymer/organoclay couples gave thermodynamically stable intercalated/exfoliated structures. Nevertheless, the highest levels of exfoliation, together with excellent dispersion of the clay particles, have been obtained for the nanocomposites prepared by melt compounding from polymer–clay couples with optimal match of polar characteristics.