Intercalation and in situ polymerization of poly(alkylene oxide) derivatives within M+-montmorillonite (M = Li, Na, K)

Abstract

We have synthesized a range of montmorillonite-based clay–polymer nanocomposites by intercalation of a variety of functionalized molecules having poly(ethylene oxide) and poly(propylene oxide) backbones from aqueous solution using a facile batch process. We focus on montmorillonite clays charge-balanced by cation exchange with Li+ and K+, but otherwise unmodified. Analysis by X-ray diffraction and thermal methods showed that intercalation occurred in all cases and that the composites displayed a range of interlayer spacings and organic content, from monolayer arrangements to pseudo-trilayer arrangements. Intercalated K+-montmorillonites had a propensity to exfoliate, in marked contrast to their resistance to swelling by water. Large-scale molecular dynamics simulations of selected composites were used to elucidate possible interlayer arrangements of the composites. Materials property studies showed that these clay–polymer composites had significantly increased Young's moduli compared to the unfilled polymer.