The supercritical conditions of CO2 are easily reached
Supercritical CO2 is the most common of these applications. It is a clean, versatile solvent and promises to replace toxic organic solvents and chlorofluorocarbons. Just as in the field of polymer processing, as a supercritical fluid in the synthesis, due to its attractive physical properties, it has attracted people's special attention. Carbon dioxide is non-toxic, non-flammable, chemically inert, and inexpensive. Carbon dioxide is non-toxic, non-flammable, chemically inert, and inexpensive. Although carbon dioxide is abundant in the atmosphere, a large amount of carbon dioxide can also be obtained as a byproduct from ammonia, hydrogen and ethanol.
The supercritical condition of carbon dioxide is easily reached (critical temperature 304K, critical pressure 7.38 MPa). And can be separated from the system by a simple step-down. In addition, many polymers react with CO2 to become highly swelled and plasticized, allowing the process to proceed at low temperatures. Because of the recovery during processing, the use of supercritical CO2 does not cause greenhouse effect problems.