Aromatic poly (ether sulfone imide) membranes for gas separations

A process for separating at least one gas from a mixture of gases or at least one liquid from a mixture of liquids comprising providing an aromatic poly(ether sulfone imide) polymer membrane or a cross-linked aromatic poly(ether sulfone imide) polymer membrane;

• contacting the mixture of gases or the mixture of liquids to one side of the aromatic poly(ether sulfone imide) polymer membrane or the cross-linked aromatic poly(ether sulfone imide) polymer membrane to cause at least one gas or at least one liquid to permeate said membrane;
• and removing from an opposite side of said aromatic poly(ether sulfone imide) polymer membrane or said cross-linked aromatic poly(ether sulfone imide) polymer membrane a permeate gas composition or a permeate liquid composition comprising a portion of said at least one gas or said at least one liquid that permeated said membrane wherein said aromatic poly(ether sulfone imide) polymer membrane comprises a plurality of repeating units of formula (I)
• wherein X1 is selected from the group consisting of
• and mixtures thereof;
• wherein Y1 is selected from the group consisting of
• and mixtures thereof;
• wherein Y2 is selected from the group consisting of
• and mixtures thereof;
• n, m, o and p are independent integers from 2 to 500;
• and the molar ratio of (n+o)/(m+p) is in a range of 1:10 to 10:1.