John M Pacheco

US Patent:

61268267, Oct 3, 2000

Filed:

Aug 5, 1997

Appl. No.:

8/906074

Inventors:

Manuel M. Pacheco - Billerica MA
John F. Pacheco - Billerica MA

Assignee:

Whatman Inc. - Haverhill MA

International Classification:

B01D 3900

US Classification:

21050042

Abstract:

Methods for making microporous polyvinylidene fluoride (PVDF) membranes from vinylidene fluoride polymers and the products produced. The PVDF microporous membranes have a significantly faster flow rate at a given pore size as compared to equally-sized microporous membranes made by conventional procedures. The PVDF microporous membranes also have significantly smaller pore sizes than conventional microporous PVDF membranes. The present membranes have unique macrostructural features responsible, in part, for their unique functional properties. The process includes dissolving the polymer in a liquid that includes a solvent and a co-solvent for the polymer. The dissolution of the polymer can be at temperatures ranging from about 20. degree. C. to about 50. degree. C. while the formation of the microporous membrane can be at temperatures ranging from about -10. degree. C. to 50. degree. C.

US Patent:

53762738, Dec 27, 1994

Filed:

Jun 25, 1993

Appl. No.:

8/082308

Inventors:

Manuel M. Pacheco - Billerica MA
John F. Pacheco - Billerica MA

Assignee:

Costar Corporation - Cambridge MA

International Classification:

B01D 2900

US Classification:

210490

Abstract:

Microporous membranes having supporting structures are disclosed. A microporous filtration membrane made of a polymeric material has an integral support, both the support and the membrane having substantially identical chemical composition. Preferred supported membranes of the present invention are made of polyvinylidene fluoride. At least part of the support is bonded to the surrounding microporous membrane to provide rigidity and chemical inertness. Methods of forming the supported microporous membranes are described, including a method that results in microporous membranes having unique structural and functional characteristics.

US Patent:

47612304, Aug 2, 1988

Filed:

Jun 11, 1987

Appl. No.:

7/061846

Inventors:

John F. Pacheco - Billerica MA
Donald B. Rising - Stow MA

Assignee:

Millipore Corporation - Bedford MA

International Classification:

B01C 1300

US Classification:

21032184

Abstract:

A filter system particularly useful with small sample volumes includes first and second housing sections with a flow channel extending therebetween. A membrane filter forms one boundary of the flow channel. A pair of reservoirs, one for feed and the other for permeate collection, are integrally formed with the first housing section. A fluid communication path is established from the first section to the second section and then through means of a deformable chamber to the flow channel. The deformable chamber is adjacent to a rigid surface that is integral with one of the housing sections and in this manner is adapted to pump fluid through the system when interfacing with a pump.

US Patent:

6013688, Jan 11, 2000

Filed:

Mar 18, 1996

Appl. No.:

8/618982

Inventors:

Manuel M. Pacheco - Billerica MA
John F. Pacheco - Billerica MA

Assignee:

Corning Costar Corporation - Acton MA

International Classification:

C08J 928

US Classification:

521 64

Abstract:

Methods for making microporous polyvinylidene fluoride (PVDF) membranes from vinylidene fluoride polymers and the products produced. The PVDF microporous membranes have a significantly faster flow rate at a given pore size as compared to equally-sized microporous membranes made by conventional procedures. The PVDF microporous membranes also have significantly smaller pore sizes than conventional microporous PVDF membranes. The present membranes have unique macrostructural features responsible, in part, for their unique functional properties. The process includes dissolving the polymer in a liquid that includes a solvent and a co-solvent for the polymer. The dissolution of the polymer can be at temperatures ranging from about 20. degree. C. to about 50. degree. C. while the formation of the microporous membrane can be at temperatures ranging from about -10. degree. C. to 50. degree. C.