| This thesis summarizes the research into processing polymers using supercritical carbon dioxide, conducted at the Georgia Institute of Technology from September 1993 to December 1996. The main tools utilized in this research are FTIR spectroscopy and novel high pressure cells that were designed by M. F. Vincent and S. G. Kazarian and constructed at the Georgia Institute of Technology School of Chemical Engineering machine shop by J. Andrews. Through this research we have demonstrated that carbon dioxide is not an inert species, indeed it actually participates in specific interactions with functional groups present in glassy polymers through a Lewis acid base type complex. We have utilized the plasticization ability of CO{dollar}sb2{dollar} to study the enhanced diffusion of deuterated water in CO{dollar}sb2{dollar}-swollen poly(methyl methacrylate). The implications of the diffusion work relate directly to the polymerization of polyacrylates and polystyrene in supercritical carbon dioxide. We have also analyzed the viability of supercritical fluid chromatography as a tool to measure thermophysical properties. This work has shown reliable and accurate measurements require knowledge of the partitioning of all species present in the system, in the general case this includes the fluid, solute and cosolvent. In lieu of this information, predictive equations of state for the polymer phase may prove beneficial in measuring thermophysical properties via supercritical fluid chromatography. |
