Investigating the effect of dianhydride type and pyrolysis condition on the gas separation performance of membranes derived from blended polyimides through statistical analysis

In this study, properly designed experiments are utilized to improve and optimize the main parameters including the selection of precursors with different molecular structures, blend composition of precursors and conditions of carbonization. Optimum conditions are met for UIP-R/PBI, at blend composition of 94% and pyrolysis temperature of 620 °C at 10−7 Torr. Under such conditions, the model estimated permeability of CH4 and CO2 equal to 26.7 and 310 Barrer, while measured selectivity responses of CO2/CH4 is 77.5, respectively. As a result, greater values of separation efficiency are achieved in the range of 0.88–0.97 polyimide content in these blends.