The degradation and stabilization of polyacrylonitrile. I. Evidence for β‐ketonitrile defect structures as initiators of degradation

Abstract The theory that β‐ketonitrile structures initiate discoloration reactions in polyacrylonitrile has been tested by a number of methods. Using radiochemical techniques the numbers of carbonyl groups in various polymers have been measured as have the amounts of combined water. A model β‐keto compound, 1,3,7,‐tricyanoheptan‐4‐one was synthesized and its reactions studied. None of these experiments supported the idea that β‐ketonitrile structures are of primary importance in initiating the degradation of polyacrylonitrile.