posted on 2023-01-06, 16:03authored bySomi Yu, Seong Jin An, Ki Jung Kim, Jae Hun Lee, Won Seok Chi
Poly(ethylene glycol) (PEG) is an amorphous material
of interest
owing to its high CO2 affinity and potential usage in CO2 separation applications. However, amorphous PEG often has
a low molecular weight, making it challenging to form into the membrane.
The crystalline high average molar mass poly(ethylene oxide) (PEO)
cannot exhibit CO2 separation characteristics. Thus, it
is crucial to employ low molecular weight PEG in high molecular weight
polymers to increase the CO2 affinity for CO2 separation membranes. In this work, poly(acrylic acid) (PAA)/PEG
blend membranes with a PEG-rich phase were simply fabricated by physical
mixing with an ethanol solvent. The carbonyl group of the PAA and
the hydroxyl group of the PEG formed a hydrogen bond. Furthermore,
the thermal stability, glass transition temperature, and surface hydrophilicity
of PAA/PEG blend membranes with various PEG concentrations were further
characterized. The PAA/PEG(1:9) blend membrane exhibited an improved
CO2 permeability of 51 Barrer with high selectivities relative
to the other gas species (H2, N2, and CH4; CO2/H2 = 6, CO2/N2 = 63, CO2/CH4 = 21) at 35 °C and 150
psi owing to the enhanced CO2 affinity with the amorphous
PEG-rich phase. These PAA/PEG blend membrane permeation characteristics
indicate a promising prospect for CO2 capture applications.