(164a) Dispersion of Nanoclay in Linear Low-Density Polyethylene (LLDPE) and Maleated Linear Low-Density Polyethylene (LLDPE-g-MA) in Supercritical Carbon Dioxide

Addition of nanoclay to polymer is often desirable due to the ability of the nanoclay to improve the thermo-mechanical and barrier properties as well as flame retardancy of the polymer. The degree of property enhancement by the nanoclay is largely dependent on how well it is dispersed throughout the polymeric system. However, complete or nearly complete dispersion is difficult to achieve. Supercritical carbon dioxide is one technique that has the potential to achieve a high level of dispersion. Organo-nanoclay Cloisite 93A dispersion was attempted in linear low-density polyethylene (LLDPE) and linear low-density polyethylene grafted with maleic anhydride (LLDPE-g-MA) via supercritical carbon dioxide at various processing conditions. According to x-ray diffraction (XRD) analysis, both LLDPE and LLDPE-g-MA pellets experience nanoclay dispersion into the pellet, but these polymers have different run conditions that result in a better nanocomposite. This is most likely due to the grafted maleic anhydride that increases the compatibility between LLDPE and Cloisite 93A. Besides being a means of effective dispersion, it is conceivable that supercritical carbon dioxide may be used to exfoliate nanoclays which can further enhance the resultant nanocomposite properties.