Nanostructure morphology and dynamic rheological properties of nanocomposites based on thermoplastic polyurethane and organically modified montmorillonite

Thermoplastic polyurethane (TPU) nanocomposites based on organophilic-layered silicates were prepared via melt blending. Wide angle X-ray diffraction (WAXD) and transmission electron microscope (TEM) were employed to investigate the state and mechanism of exfoliation of the layered silicate within TPU matrix. The TPU nanocomposites were found to have a partially exfoliated morphology at lower clay loading, whereas the morphology changed to an intercalated nanostructure at higher clay loadings. The effect of the state of dispersion of organoclay on rheological properties of the nanocomposites were carried out by rubber process analyzer (RPA), which exhibited more pronounced shear thinning behavior, and increased storage and loss modulus with the increase in organoclay content. The pseudo-plastic like behavior was observed due to change in liquid-like to solid-like behavior of nanoclay-filled systems.