Patents by Inventor Warella R. Browall

Warella R. Browall has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4192842
    Abstract: An improved method is described for solvent casting ultrathin non-porous methylpentene polymer films. The casting solution comprises methylpentene polymer or a mixture thereof with organopolysiloxane-polycarbonate copolymer dissolved in a solvent system and is characterized by being able to spontaneously spread over the surface of the liquid casting substrate. In a preferred embodiment, large-area films less than 200 Angstroms in thickness may be repeatedly formed. The solidified films remain relatively free of tensile stress during formation. The casting solution is deposited in a narrow, longitudinally-extending defined region at the surface of the casting substrate. The surface area and perimeter of the defined region are enlarged over the surface of the casting substrate in a manner whereby the casting solution is moved relative to the casting substrate and, after desolvation, the polymer film formed remains stationary relative to the casting substrate and relatively free of tensile stress.
    Type: Grant
    Filed: October 10, 1978
    Date of Patent: March 11, 1980
    Assignee: General Electric Company
    Inventors: Shiro G. Kimura, Raymond G. Lavigne, Warella R. Browall
  • Patent number: 4156597
    Abstract: Disclosed is an ultrathin permselective polyetherimide membrane having an average thickness of less than about 10 microns and formed of a polymeric composition comprising a polyetherimide prepared by reacting metaphenylenediamine and certain aromatic bis(ether anhydride)s. A gas separation process employing the membrane is also disclosed.
    Type: Grant
    Filed: September 23, 1977
    Date of Patent: May 29, 1979
    Assignee: General Electric Company
    Inventor: Warella R. Browall
  • Patent number: 4155793
    Abstract: A composite laminar membrane including a flexible microporous support layer and at least one ultrathin permeable nonporous polymeric membrane of 500 angstroms or less in thickness is prepared by a continuous process. A liquid substrate having a well in its upper surface is provided and polymer-containing casting solution is continuously supplied to the well to effect continuous solution spreading across the liquid surface. Solvent is removed and a web of the support material is continuously contacted with the resulting ultrathin membrane to continuously remove it upwardly from a region of the liquid surface. In a preferred embodiment, an additional well spaced from the removal region is employed for producing an additional membrane, which is continuously removed from its liquid surface in contiguous contact with the liquid-contact surface of the first membrane.
    Type: Grant
    Filed: November 21, 1977
    Date of Patent: May 22, 1979
    Assignee: General Electric Company
    Inventors: Robert M. Salemme, Warella R. Browall
  • Patent number: 4132824
    Abstract: An improved method is described for solvent casting ultrathin non-porous methylpentene polymer films. The casting solution comprises methylpentene polymer of a mixture thereof with organopolysiloxane-polycarbonate copolymer dissolved in a solvent system and is characterized by being able to spontaneously spread over the surface of the liquid casting substrate. In a preferred embodiment, large-area films less than 200 Angstroms in thickness may be repeatedly formed. The solidified films remain relatively free of tensile stress during formation. The casting solution is deposited in a narrow, longitudinally-extending defined region at the surface of the casting substrate. The surface area and perimeter of the defined region are enlarged over the surface of the casting substrate in a manner whereby the casting solution is moved relative to the casting substrate and, after desolvation, the polymer film formed remains stationary relative to the casting substrate and relatively free of tensile stress.
    Type: Grant
    Filed: July 21, 1977
    Date of Patent: January 2, 1979
    Assignee: General Electric Company
    Inventors: Shiro G. Kimura, Raymond G. Lavigne, Warella R. Browall
  • Patent number: 3980456
    Abstract: A method is described for sealing pinholes and covering imperfections passing through a multi-layer membrane composite to be employed for conducting a gas separation process. The particular breaches through such composites that this invention is intended to deal with are those caused by the unavoidable presence of particles smaller than about 3000 A. By this method an additional ultrathin membrane of very flexible, permeable polymer material is applied over the outer surface of the membrane composite.
    Type: Grant
    Filed: March 31, 1975
    Date of Patent: September 14, 1976
    Assignee: General Electric Company
    Inventor: Warella R. Browall