Supercritical fluids have received widespread attention as processing fluids, but virtually no attention as media in which to carry out chemical transformations. The potential advantages of using a supercritical fluid reaction as a medium are that it may be possible to increase the selectivity of a reaction while maintaining high conversions, to dissolve reactants and catalyst in a single fluid phase so that the reaction occurs homogeneously, and to improve or greatly facilitate the separation of products from reactants, catalyst, and unwanted byproducts by utilizing the phase behavior exhibited by the mixture in its critical region. The goal of this research is to determine how the variables in supercritical fluids affect the products and kinetic parameters of photoinitiated polymerization processes. Systematic studies to determine chain-reaction parameters, such as initiator cage effects, oligomer/polymer dispersivity, oligomer/polymer stereochemistry, inhibition rate constants, and initiator energy-transfer quenching parameters will be carried out in carbon dioxide as a function of temperature and pressure.
