The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 27, 1991
Filed:
Mar. 21, 1990
Applicant:
Inventors:
Assignee:
W. R. Grace & Co.-Conn., New York, NY (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
B01D / ; B01D / ;
U.S. Cl.
CPC ...
55 16 ; 55158 ; 528313 ;
Abstract
A novel class of polyimides useful in making semipermeable membranes for gas separation is synthesized by the reaction of 4,4'-[hexafluoroisopropylidene]-bis-[phthalic anhydride] (6FDA) with 3,7-diamino-2,8-dimethyldiphenylenesulfone (AMPS). In lieu of the two methyl groups the diamine may be substituted by H or C.sub.2-4 alkyl. Membranes made from the polyimides have high permeability for CO.sub.2 from mixtures containing CO.sub.2 and other gases such as CH.sub.4 and have commercially acceptable selectivity.