Fabrication of co-continuous morphology of polysulfone/nylon 6, 6 nanocomposites by varying the concentration of organically modified clay content

Abstract

A unique morphology was fabricated using melt mixing of polysulfone (PSU) and nylon 6, 6, as well as organically modified clay to produce two blended nanocomposite compositions (80/20 and 60/40 w/w) of polysulfone and nylon 6, 6. The morphology of PSU/Nylon 6, 6 blend nanocomposites with various amounts of clay has been examined using scanning electron microscope (SEM), transmission electron microscope (TEM), and wide-angle X-ray diffraction (WAXD). In the case of 80/20 (w/w) PSU/Nylon 6, 6 without clay, the Nylon 6, 6 is dispersed in the PSU matrix with an average particle size of about 6.81 micrometers (μm). After adding clay (2%, 4%, and 8%), the domain size of nylon 6, 6 decreases, although the decrease rate is much slower than initially observed. However, we discovered that when the organoclay level exceeds 2%, the matrix-domain structure transforms into a co-continuous morphology for the 60/40 (w/w) blends. The TEM studies clearly demonstrate that the organoclay preferentially positions itself in the nylon 6, 6 phase, exhibiting a high degree of exfoliation, while the PSU phase of the nanocomposites remains devoid of clay, irrespective of the amount present. This study indicates that the size of clay platelets dispersed in the PSU/Nylon 6, 6 blend plays an important role in determining the morphology and stability of these blends. Moreover, the co-continuous structures were stable against further annealing at high temperatures, thus inhibiting the coalescence of the dispersed phase in addition to reducing interfacial tension.