Influence of Clay Surface Modification on Morphology and Rheology of Polyethylene Glycol/Montmorillonite Nanocomposites

The effects of surface modification of Na-montmorillonite (Na-MMT) on morphology and the rheological properties of polyethylene glycol/ organoclay nanocomposites are investigated. Dodecyltrimethylammonium bromide (DTABr) is used to modify the clay surface. Adsorption of DTABr on Na-MMT is monitored by zeta potential measurements. From zeta potential measurements, three DTABr concentrations, 1 × 10—3, 7.5 × 10— 3, and 5 × 10—2 mol/L, are chosen to fabricate the polyethylene glycol/organoclay composites. The morphology of three sets of organoclays (OMMT1, OMMT2, and OMMT3) is studied by X-ray diffraction (XRD) technique. The increase of basal spacing is found to be 0.2 nm as the DTABr concentration is increased to 7.5 × 10— 3 mol/L. The rheological properties of polyethylene glycol (PEG)/ organoclay nanocomposites are studied for three organoclays at different PEG concentrations. All nanocomposites show Bingham plastic flow behavior. The OMMT3 shows maximum viscoelastic properties in the polymer matrix. The...