Preparation and Properties of Polysulfone–Poly(ethylene glycol) Graft Copolymer Membrane

In this study, Graft copolymers composed of PSf backbones and PEG side chains were synthesized to prepare gas separation membranes with enhancing permeability and selectivity on carbon dioxide separation. PSf-g-PEG copolymers were synthesized by two steps, chloromethylation and graft reactions. Grafted PEG segment of PSf was controlled by molecular weight of PEG. Thermal properties of prepared mebrane were studied by TGA and DSC. T_g of the copolymers was decreased with increasing of molecular weight of PEG. Hydrophilicity of PSf-g-PEG copolymer membrane was measured using contact angle method, and PEG grafted polymers showed lower contact angles due to higher hydrophilicity. Gas permeation properties of CO₂ and N₂ gases through the membranes were measured using time-lag method. The permeability of CO₂ was enhanced with PEG moiety contents and increasing of number of PEG segment. The selectivity of CO₂/N₂ was increased with introducing of PEG due to higher solubility with CO₂ gas.