Patents by Inventor David S. Campbell

David S. Campbell 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).

  • Reagents for graft copolymers
    Patent number: 4501860
    Abstract: A hydroxyl-functional polymer is reacted with a compound ZCO.N(H).sub.x.N(H).sub.x.CO.OR, where Z is halogen or aryloxy, x is 0 or 1 and R is hydrocarbon, and the reaction product is if necessary oxidized to give an azodicarboxylate functional polymer having the formula QOCO.N:N.CO.OR where Q is an inert polymer group. This polymer is used to react with ethylenically unsaturated natural or synthetic rubber so as to graft groups derived from the polymer on the rubber backbone.
    Type: Grant
    Filed: May 4, 1982
    Date of Patent: February 26, 1985
    Assignee: The Malaysian Rubber Producers' Research Association
    Inventors: David S. Campbell, Andrew J. Tinker, Peter G. Mente
  • Method of forming graft copolymers by attaching pre-polymerized side chains to a natural or unsaturated synthetic rubber backbone, and the resulting graft copolymers
    Patent number: 4221681
    Abstract: Graft copolymers having thermoplastic elastomeric properties are formed by intimately blending together at elevated temperature in the solid state in e.g. an internal mixer (a) an ethylenically unsaturated natural or synthetic rubber and (b) a pre-polymer of a vinyl aromatic monomer having an azodicarboxylate end group reactive towards unsaturated groups of the rubber.
    Type: Grant
    Filed: July 25, 1978
    Date of Patent: September 9, 1980
    Assignee: The Malaysian Rubber Producers' Research Association
    Inventors: David S. Campbell, David E. Loeber, Andrew J. Tinker