Effect of supercritical carbon dioxide processing on layered-silicate nano-clays.

摘要

Several attempts to fully exfoliate layered-silicate nano-clays in a polymer matrix have been made by various research organizations in the past decade or so. The objective behind trying to fully exfoliate the nano-clay tactoids into individual bodies is to maximize the utility of their available surface area (∼760 m2/g) in the presence of favourable polymer-clay interactions to produce high-performance polymer nanocomposites with very little loading of nano-clays in the polymer matrix. Contemporary methods of nano-clay dispersion include in-situ polymerization, solvent casting and mechanical melt mixing.; In this MS Thesis, an attempt has been made to achieve nano-clay dispersion in primarily three nano-clays using supercritical carbon dioxide (scCO 2) as a process fluid. Two of these nano-clays are scCO2-philic and one is scCO2-phobic. By analyzing their X-Ray Diffraction (XRD) spectra and their Scanning Electron Microscopy (SEM) images before and after scCO2 processing, reasons for the observed change in the nano-clay morphology or lack thereof have been proposed. The effect of each processing parameter on the extent of dispersion produced has also been discussed.