According to their dimensions the polymeric parts (injection molded parts or pellets, powder etc.) are arranged in the high pressure autoclave (63 mL, 1,5 L, 2 L, 20 L, 1700 L). Depending on the aggregation state (e.g. liquid, powder form) the additive is added inside the autoclave. Pressurizing the autoclave with CO2 initiates the impregnation process. CO2 acts as a molecular lubricant enabling substances to pass the polymeric matrix. To intensify the absorbing capacity of the polymer the process chamber can be heated during the process (usually not above 100 °C). Finally the autoclave is depressurized (the CO2 can be reused in the next process) and the parts can be removed. The parts are now impregnated.