Patents by Inventor Marion R. DeWitt, Jr.

Marion R. DeWitt, Jr. 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).

  • Process for increasing the relative viscosity of polyamides with reduced thermal degradation
    Patent number: 5116919
    Abstract: A process for increasing the relative viscosity of a polyamide includes heating the polyamide in the presence of a base and a catalyst with the catalyst being at least one compound of the formula:X--(CH.sub.2).sub.n PO.sub.3 R.sub.2wherein X is 2-pyridyl, 4-morpholino, 1-pyrrolidino, 1-piperidino or R'.sub.2 --N-- wherein R' is an alkyl group having between 1 and 12 carbon atoms;n is an integer from 2 to 5; andR, being the same or different, is H or an alkyl group having between 1 and 12 carbon atoms.
    Type: Grant
    Filed: December 5, 1990
    Date of Patent: May 26, 1992
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: John F. Buzinkai, Marion R. DeWitt, Jr., Robert C. Wheland