Chemical modification of polyimides
AssigneeInstitute of Materials Research and Engineering
InventorsYe Liu, Dong-Fei Li, Rong Wang, Tai-Shung Chung
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Abstract
A process for chemically modifying a dual-layer hollow fibre, wherein said fibre comprises a first layer consisting essentially of a polyimide and a second layer consisting essentially of a polymer which is substantially unaffected by the chemical modification process, which process comprises contacting said polyimide layer with a polyamine. A process for chemically modifying a polyimide membrane in general, which process comprises contacting said membrane with an alcoholic solution of an aliphatic-aromatic polyamine.
Claims44
A process for chemically modifying a dual-layer hollow fibre, wherein said fibre comprises a first layer consisting essentially of a polyimide and a second layer consisting essentially of a polymer which is substantially unaffected by the chemical modification process, which process comprises contacting said polyimide layer with a polyamine.
A process as claimed in any preceding claim wherein the polyamine contacts only one side of the polyimide layer.
A process as claimed in any preceding claim wherein the polyimide layer is contacted with the polyamine at a temperature in the range of from 5° C. to 50° C.
A process as claimed in any preceding claim wherein the polyimide layer is contacted with the polyamine at a temperature in the range of from 15° C. to 30° C.
A process as claimed in any preceding claim wherein the polyamine is in the form of a solution in a suitable solvent when it is contacted with the polyimide layer.
A process as claimed in any preceding claim wherein, at the end of the process, the dual-layer hollow fibre is dried at a temperature in the range of from 5° C. to 80° C.
A process as claimed in any preceding claim wherein, at the end of the process, the dual-layer hollow fibre is dried at a temperature in the range of from 15° C. to 40° C.
A process as claimed in any preceding claim wherein the polyimide layer is an aromatic polyimide membrane.
A process as claimed in any preceding claim wherein the polyimide layer consists essentially of the following structural units:
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- where each of the n Ar1 groups is a quadrivalent aromatic moiety independently selected from the group consisting of:
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- and where each of the n Ar2 groups is a bivalent aromatic moiety independently selected from the group consisting of:
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- where Z is selected from the group consisting of:
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- and where X, X1, X2 and X3 are each independently selected from hydrogen, C1-5alkyl, C1-5alkoxy, phenyl or phenoxy.
A process as claimed in any preceding claim wherein the polyamine is an aliphatic-aromatic polyamine.
A process as claimed in any preceding claim wherein the polyamine is an aliphatic-aromatic diamine.
A process as claimed in any preceding claim wherein the polyamine is an aliphatic-aromatic diamine having the general structure:
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A process as claimed in any preceding claim wherein the polyamine is selected from m-xylylenediamine or p-xylylenediamine.
A process as claimed in any preceding claim wherein the polyamine is contacted with the polyimide layer in the form of a solution having a concentration of polyamine of from 2 wt % to 50 wt % based on the total weight of the solution.
A process as claimed in any preceding claim wherein the polyamine is contacted with the polyimide layer in the form of a solution having a concentration of polyamine of from 2 wt % to 20 wt % based on the total weight of the solution.
A process as claimed in any preceding claim wherein the polyamine is contacted with the polyimide layer in the form of a solution having a concentration of polyamine of from 5 wt % to 10 wt % based on the total weight of the solution.
A process for chemically modifying a polyimide membrane, which process comprises contacting said membrane with an alcoholic solution of an aliphatic-aromatic polyamine.
Dependencies are inferred from the claim text.