Shear-induced orientation in polymer/clay dispersions via in situ X-ray scattering

摘要: Abstract We report in situ X-ray scattering measurements of shear-induced orientation polymer–clay dispersions. Two different organically modified clays, montmorillonite and fluorohectorite, are dispersed a low molecular weight, viscous polymer melt, facilitating studies at room temperature. Orientation performed the flow-gradient plane, allowing characterization both average degree direction particle during shear. In all cases, angle is finite, indicating systematic misalignment long axes relative to flow direction. concentrated fluorohectorite dispersions, anisotropy roughly independent shear rate, negligible relaxation observed upon cessation. Conversely, lower concentration sample exhibits that more responsive flow, partially relaxes this sample, behavior interpreted light rotational diffusion clay particles. This same oscillatory structural dynamics reversal, attributed tumbling rotations disk-like particles Large-amplitude similarly demonstrated be capable inducing significant orientation; principally determined by applied strain amplitude. Complementary rheological properties exhibit many characteristics commonly reported nanocomposites. Based on here, phenomena arise from combination flow-induced rate- time-dependent destruction or reformation networks.