Brominated Poly(2,6-diphenyl-1,4-phenylene oxide) and Its Silica Nanocomposite Membranes for Gas Separation.

Brominated poly(2,6-diphenyl-1,4-phenylene oxide) (BPPOdp) is synthesized as a new membrane material for gas separation. BPPOdpforms flexible membranes with higher CO2permeability (PCO278 Barrer) and selectivity (CO2/N230) than poly(2,6-dimethyl-1,4-phenylene oxide) (PPOdm) membranes. BPPOdpalso forms nanocomposite membranes with silica nanoparticles. The nanocomposite membranes have a greatly enhanced CO2permeability while maintaining the CO2/N2and CO2/CH4selectivities of the pure BPPOdpmembranes. The CO2permeability increases as the silica content increases in the membrane. The 10-nm silica nanoparticles are more effective at increasing the CO2permeability than the 30-nm silica nanoparticles. Mechanism studies show that the enhanced permeability results from the nanogaps between the silica nanoparticles and the polymer chains due to their incompatibility. [ABSTRACT FROM AUTHOR]