POLYIMIDE BLEND MEMBRANES FOR GAS SEPARATIONS

摘要

The polyimide blend membrane in the present invention was prepared by blending a first aromatic polyimide with high permeability and a second aromatic polyimide with high selectivity for gas separation. The polyimide blend membrane in the present invention showed improved permeability compared to membranes made from the second aromatic polyimide and improved selectivity compared to membranes made from the first aromatic polyimide.

主权项

1. A process for separating at least one gas from a mixture of gases, the process comprising
(a) providing a polyimide blend membrane comprising a miscible blend of a first aromatic polyimide that comprises a plurality of repeating units of formula (I) and a second aromatic polyimide that comprises a plurality of repeating units of formula (II), wherein formula (I) is represented by: wherein n, m, o, and p are independent integers from 20 to 500; and wherein formula (II) is represented by: wherein q and r are independent integers from 20 to 500; and wherein the weight ratio of said first aromatic polyimide to said second aromatic polyimide is in a range from about 10:1 to 1:10 wherein said polyimide blend membrane is permeable to said at least one gas; (b) contacting a mixture of gases to one side of the polyimide blend membrane to cause said at least one gas to permeate the polyimide blend membrane; and (c) removing from an opposite side of the polyimide blend membrane a permeate gas composition comprising a portion of said at least one gas which permeated said membrane.