Patents Examined by M. Nugumo
  • Polymerization of maleic anhydride
    Patent number: 5077364
    Abstract: Polymaleic anhydride having a weight average molecular weight by gel permeation chromatography of between 450 and 800 and a polydispersivity of between 1.0 and 1.15 is produced by polymerizing maleic anhydride, using a peroxide initiator in an amount not greater than 10% by weight of the anhydride, in a dilute solution in o-xylene or a substituted o-xylene.
    Type: Grant
    Filed: February 7, 1990
    Date of Patent: December 31, 1991
    Assignee: Ciba-Geigy Corporation
    Inventors: Jan Rideout, Duncan J. MacQuarrie