Structural characterization of hydrophilic polymer blends/montmorillonite clay nanocomposites

Abstract

The nanocomposite films comprising polymer blends of poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), poly(ethylene oxide) (PEO), and poly(ethylene glycol) (PEG) with montmorillonite (MMT) clay as nanofiller were prepared by aqueous solution casting method. The X-ray diffraction studies of the PVA-x wt % MMT, (PVA-PVP)-x wt % MMT, (PVA-PEO)-x wt % MMT and (PVA-PEG)-x wt % MMT nanocomposites containing MMT concentrations x=1, 2, 3, 5 and 10 wt % of the polymer weight were carried out in the angular range (2θ) of 3.8-30°. The values of MMT basal spacing d001, expansion of clay gallery width Wcg, d-spacing of polymer spherulite, crystallite size L and diffraction peak intensity I were determined for these nanocomposites. The values of structural parameters reveal that the linear chain PEO and PEG in the PVA blend based nanocomposites promote the amount of MMT intercalated structures, and these structures are found relatively higher for the (PVA-PEO)-x wt % MMT nanocomposites. It is observed that the presence of bulky ester-side group in PVP backbone restricts its intercalation, whereas the adsorption behavior of PVP on the MMT nanosheets mainly results the MMT exfoliated structures in the (PVA-PVP)-x wt % MMT nanocomposites. The crystallinities of the PEO and PEG were found low due to their blending with PVA, which further decreased anomalously with the increase of MMT concentration in the nanocomposites. The decrease of polymer crystalline phase of these materials confirmed their suitability in preparation of novel solid polymer nanocomposite electrolytes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40617. Copyright © 2014 Wiley Periodicals, Inc.