Patent ID: 11878284
Assignee: AVANPORE LLC
Field: Chemical engineering (Chemistry)
Classification: CPC B  C | IPC B  C

Claim 0:
1. A process of forming an asymmetric porous hollow fiber membrane comprising the steps of:
(a) forming a blend of a poly (aryl ether ketone) polymer with a polyimide;
(b) forming a hollow fiber shaped article from the blend by melt processing, wherein the article is substantially amorphous;
(c) subjecting a surface of the article to a solvent treatment step that induces mobility of polymeric chains in the blend to cause crystallization in the article only to a predetermined depth in order to define a surface layer and an interior portion, the surface layer exhibiting a crystallization morphology while the interior portion remains substantially amorphous;
(d) subjecting the article, subsequent to step (c), to a second crystallization step to complete crystallization such that both the surface layer and the interior portion exhibit crystallization morphologies, wherein the crystallization morphology exhibited by the surface layer is different as compared to the crystallization morphology exhibited by the interior portion despite both the surface layer and the interior portion being formed in step (b) from the same blend formed in step (a);
(e) bringing the article into contact with a solution of primary amine or hydrazine to affect decomposition of the polyimide; and
(f) removing products of polyimide decomposition from the article.