Suppression of gas separation membrane plasticization by homogeneous polymer blending

Plasticization is a phenomenon frequently encountered in the application of glassy polymeric materials for. solution - diffusion membranes. Convention al methods for stabilising the membrane are either annealing or cross-linki ng, which hardly influence rite selectivity of the membrane, but decrease t ire permeability. For single-gas experiments, the literature shows that pla sticization can be stabilized by blending a polymer with high plasticizatio n tendencies with one that is hardly affected by the sorbed molecules, Most permeation experiments are carried out with pure CO2, but little is known about the transport properties determined front mixed gas experiments. Stab ilization of plasticization in mixed-gas experiments for polymer blends of the polyimide Matrimid and polysulfone is reported as well as transport pro per-ties of a new homogeneous polymer blend based on Matrimid and the copol yimide P84. Experimental results show that the material is stabilized again st carbon dioxide plasticization and selectivity for a carbon dioxide/metha ne mixture significantly improves.