Patent ID: 8132677
Filing Date: 2012-03-13
Classification: B01D,C08G,C08L,Y02C

Abstract:
1. A polymer membrane made from subjecting aromatic polyimide membranes first to a thermal treatment step followed by a crosslinking step wherein said aromatic polyimide membranes comprise at least one aromatic polyimide polymer comprising cross-linkable functional groups in a polymer backbone of said aromatic polyimide polymer and pendent hydroxyl functional groups ortho to a heterocyclic imide nitrogen within said aromatic polyimide polymer wherein said polymer membrane is a cross-linked polybenzoxazole or polybenzothiazole polymer membrane and wherein said aromatic polyimide polymer has a structure represented by a plurality of first repeating units of a formula (I), wherein said formula (I) is: where —X or mixtures thereof, —X or mixtures thereof, —X or mixtures thereof, —Z—, —Z′—, and —Z″— are independently —O— or —S—, and —R— is or mixtures thereof.