Preparation of copolymer membranes from hydrophilic and hydrophobic monomers and permselectivities of their membranes for aqueous ethanol solutions by pervaporation and evapomeation.

Abstract

Copolymer membranes were prepared by bulk-copolymerization of polyethylene glycol methacrylate as hydrophilic monomer and benzyl methacrylate as hydrophobic monomer in a porous support. The permeation rates in both pervaporation and evapomeation increased with increasing hydrophilic polyethylene glycole (PEG) content in the copolymer membrane. This was attributed to the fact that the copolymer membrane was swollen by aqueous ethanol solution. Separation factor had a maximum value at about 15 wt% of the PEG content in pervaporation and at about 10 wt% in evapomeation. These results were explained by the individual permeation rates for two components such as water and ethanol. An optimum PEG content for both permeability and selectivity was assumed from the permeation data. Performance of the copolymer membrane was discussed from the viewpoint of physical and chemical structures.