Polyimide gas separation membranes
Patent 4717394 Issued on January 5, 1988. Estimated Expiration Date: 
October 27, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
October 27, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References Re30351 3816303 3822202 3925211 Asymmetric polyimide membranes Selective permeable membrane and process for preparing the same Selective permeable membranes and process for preparing the same Process for producing aromatic polyimide filaments Process for preparing aromatic polyimide semipermeable membranes Gas separating material InventorAssigneeApplicationNo. 06/923486 filed on 10/27/1986US Classes:95/49, Sulfur containing compound permeates barrier210/500.39, Imide95/51, Carbon dioxide or carbon monoxide permeates barrier95/54, Oxygen permeates barrier95/55, Hydrogen permeates barrier96/4APPARATUS FOR SELECTIVE DIFFUSION OF GASES (E.G., SEMIPERMEABLE MEMBRANE, ETC.)ExaminersPrimary: Spitzer, RobertInternational ClassesB01D 71/00 (20060101)B01D 71/64 (20060101) C08G 73/00 (20060101) C08G 73/10 (20060101) AbstractSemi-flexible aromatic polyimides, prepared by polycondensation of dianhydrides with diamines having alkyl substituents on all ortho positions to the amine functions, or with mixtures of diamines, some components having substituents on all positions ortho to the amine functions, are disclosed. Membranes formed from this class of polyimides have improved environmental stability and superior gas permeability. The range of gas permeation properties observed allows for the tailoring of membrane material for widely diverse gas separations. The high permeabilities of some gases from multicomponent mixtures is due to the optimization of the molecular free volume in the polymer. | |
