Improving Co2 Separation Performances of Styrene-Butadiene-Styrene Triblock Copolymer Membranes by Tunning its Microstructure Via Varying Solvents And/Or Non-Solvents

Abstract

Microstructure in block copolymers has a critical impact on CO2 separation performances. In this work, styrene-butadiene-styrene (SBS) triblock copolymer membranes were made using various solvent/non-solvent combinations. It was found that the solvents changed their microstructure thus the CO2 separation performances were changed accordingly. CO2 permeability in the range of 203.4 to 282, and CO2/N2 selectivity in the range of 15.8 to 22.7. The highest CO2 separation performance (PCO2 282 Barrer with CO2/N2 selectivity of 20.5) was obtained using cyclohexane (CYH) as solvent. Furthermore, the CO2 separation performances of the membrane can be further improved by DI water-induced microstructure rearrangement (PCO2 343.5 Barrer and CO2/N2 selectivity 17.9). In addition, it was found that the rearranged membrane demonstrated stable gas separation performance after the membrane was stored under ambient conditions for about 120 days, clearly denoting that the CO2 separation performances of block copolymeric membranes can be tuned by varying the solvents/non-solvents.

Keywords: CO2 separation, membranes, block copolymer, microstructure rearrangement.