The utilization of supercritical fluids in the production and processing of polymers is a unique and emerging field. The Center has concentrated on the purification of polymers using supercritical fluids such as carbon dioxide. When a polymer is exposed to a supercritical fluid such as carbon dioxide, often the supercritical fluid enters the polymer and significantly swells it. This is even an effective method for inert polymers such as fluoropolymers. In the swollen state, impurities in the polymer-supercritical phase can diffuse relatively quickly and be absorbed into the external supercritical fluid. The Center has a patent that clearly shows that supercritical fluid extraction can be very effective in removing impurities from glassy polymers. In this case, there is a unique mechanism. When a supercritical fluid such as carbon dioxide is quickly removed from the polymer by depressurization, a meta-stable state exists in the glassy polymer. It takes a finite amount of time for the polymer volume to relax to its equilibrium state and during that period of time, the impurities can be quickly removed from the polymer.