Systematic investigation of methods to suppress membrane plasticization during CO2 permeation at supercritical conditions

The suppression of CO2-induced plasticization in polyimide membranes at supercritical conditions up to 120 bar is investigated. Three approaches (polymer blending, thermal treatments and chemical crosslinking) known from relatively low-pressure applications are applied their effectiveness suppress membrane high CO2 pressures under systematically identified. sorption measurements reveal that especially Henry promotes the corresponding parameter (kD) correlates with d-spacing Tg membranes. A lower higher results a reduced kD thus resistance plasticization. interchain rigidity required highly plasticizing liquid-like densities. Chemical thermo-oxidative crosslinking largest decrease mobility therefore shows highest plasticization, but also significantly permeability. Thermally treating N2 retains permeability, while still displaying significant resistance. Polymer blending does increase resistance, strongly reduces All three methods manage conditions, offers superior However, proper tailoring strategies combine