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:
Nov. 19, 1991
Filed:
Jul. 12, 1990
Binay K Dutta, Calcutta, IN;
Subhas K Sikdar, Boulder, CO (US);
The United States of America as represented by the Secretary of Commerce, Washington, DC (US);
Abstract
The present disclosure is directed to composite membranes formed by casting thin (about 8 to about 20 microns) film of perfluorosulfonic acid (PFSA) polymer on a porous matrix of polytetrafluoroethylene (PTFE). The ion exchange groups in these membranes are protons and can be substituted with metal ions such as Na.sup.+, Ca.sup.+, Ag.sup.+, etc. or by organic ligands. Alternatively, even thinner membranes (from about 1 micrometer or thinner up to 20 micrometers) can be formed by spraying a PPSA polymer solution on a porous matrix. The porous matrix may comprise polytetrafluoroethylene alone or in combination with a thermobonded polypropylene support. Both the acid and the substituted membranes have remarkable affinity for polar compounds or mixtures of polar and non-polar compounds such that azeotropic mixtures of organic compounds as well as close-boiling liquid mixtures can be easily separated at good permeation rates using the technique of pervaporation. The membrane of the present invention gives considerably higher fluxes while maintaining good separation factors. The method of the preparation of the membrane is simple and the resulting membrane is mechanically strong.