Patent ID: 8127936
Filing Date: 2012-03-06
Classification: B01D,B01J,C08G

Abstract:
1. A method for making cross-linked polybenzoxazole or polybenzothiazole polymer membranes comprising: a) first providing or synthesizing a polyimide polymer wherein said polyimide polymer contains pendent —OH or —SH groups ortho to a heterocyclic imide nitrogen and cross-linkable functional groups in a polymer backbone; b) fabricating polyimide membranes from the polyimide polymer; c) converting the polyimide membranes to polybenzoxazole or polybenzothiazole membranes comprising a first conversion step of heating between about 300° and 600° C. under inert atmosphere or vacuum for about 30 seconds to one hour; d) a second conversion step of exposing said polybenzoxazole or polybenzothiazole membranes to a crosslinking treatment; and e) coating a selective layer surface of the cross-linked polybenzoxazole or polybenzothiazole polymer membranes with a thin layer of high permeability material selected from the group consisting of a polysiloxane, a fluoro-polymer, a thermally curable silicone rubber, and a UV radiation curable epoxy silicone.