Modification of Polystyrene/Polybutadiene Block Copolymer Films by ChemicalReaction with Bromine and Effect on Gas Permeability

摘要

Permeability coefficients (P) for several gases were measured in heterogeneouspolystyrene/polybutadiene (PS/PB) block copolymer films before and after reaction with aqueous bromine. Films reacted to low and very high extents exhibited decreases in P and increases in selectivity compared to the starting material. At intermediate reaction extents, effective permeability coefficients in the reacted materials were higher than those in the unmodified films, resulting in membranes which exhibited both selectivity and permeability enhancement relative to the starting PS/PB system. These effects on permeability are the combined result of physical and chemical changes in the block copolymer films caused by the bromination reaction. Keywords: Block copolymers, Membranes, Bromination of polymers, Gas separations, Fluid mechanics, Polystyrene/polybutadiene, Chemical reaction, Gas permeability, Packaging materials, Modification. (JG)