Comparative studies on the effects of casting solvent on physico‐chemical and gas transport properties of dense polysulfone membrane used for CO₂/CH₄ separation

Abstract

The effects of casting solvents on the physico-chemical and transport properties of polysulfone membranes were investigated. Comparative analysis of the properties of membranes prepared from a new solvent (diethylene glycol dimethyether, DEG) and other commonly used solvents (1-methyl-2-pyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide and N,N-dimethylformamide) were performed using gas permeation, X-ray diffraction, scanning electron microscopy, thermogravimetric, and Fourier transform infrared spectroscopy analyses. The degree of polymer-solvent interaction was evaluated using the solvent molar volume, and Hansen and Flory-Huggins parameters. Membrane prepared from DEG displayed a relatively higher permeability of 29.08 barrer and CO 2 / CH 4 selectivity of 23.12 compared to membranes prepared from other solvents. This improved performance was attributed to the better interaction between the DEG solvent and polysulfone than other solvents that were considered. DEG has the highest molar volume of 142.

The effect of amine substituent chain length on POSS/Polysulfone mixed matrix membrane

“…Attributed to its unique structure, the repeating phenylene rings provides a rigid backbone that is resistance towards mol y y [9,10]. Furthermore, observations of high resistance towards plasticization is made with PSf membrane whereby a good permselectivity of CO 2 /CH 4 was maintained above an operating pressure of 30 bar [11,12].…”

Pebax membrane for CO2/CH4 separation: Effects of various solvents on morphology and performance

“…As explained by Kesting, during the fabrication process and film formation, the solvent acts as a transient template (spacer) and decreases the packing density of polymer chains. This can be due to the fact that at a molecular level, internodular chain segments displacements strongly depend on the size of the solvent molecules, which fold macromolecules in solution . As stated before, the d ‐spacing parameter is a measure of these interchain molecular distances, which have been reported to be one of the most important factors responsible for gas permeability through polymers.…”

“…In general, the separation properties of the membranes mainly depended on the structure and morphology of the final fabricated films. On the basis of this statement, three different mechanisms are often explained for gas transport through membranes, both porous and dense . The mechanisms include Knudsen flow, molecular sieving, and solution–diffusion.…”

Morphological control of porous membranes based on aromatic polyether/water soluble polymers

“…According to literature, the increased molar volume of the casting solvent leads to an increase in the free volume size distribution of the polymer membrane, after solvent removal. Consequently, by increasing the free volume of the membrane, the glass transition temperature ( T g ) of the polymeric system is decreasing depending on the molar volume of the casting solvent used for its preparation.…”