Patents by Inventor Dennis A. Barr

Dennis A. Barr 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).

  • Production of polyarylene ether sulphones and ketones
    Patent number: 4232142
    Abstract: Aromatic polymers containing benzenoid groups and oxygen atoms in the polymer chains are made by the action of an alkali metal hydroxide on a dihalogenobenzenoid compound in which each halogen atom is activated by an inert electron-attracting group such as --SO.sub.2 --.
    Type: Grant
    Filed: November 18, 1975
    Date of Patent: November 4, 1980
    Assignee: Imperial Chemical Industries Limited
    Inventors: Dennis A. Barr, John B. Rose