Polyacrylonitrile (PAN) and some copolymers of acrylonitrile with divinylbenzene (AN-DVB) were investigated by the characterization of their thermal and radiation stabilities. The contribution of DVB to the thermal stability of PAN by the modification in the amount of unsaturated hydrocarbon between 6 and 20% was revealed by the evaluation of oxidation induction periods and required activation energies. The exposure of these materials to the action of gamma-radiation points out the higher stability of copolymers (AN-DVB) in comparison to the relative stability of PAN. (C) 2008 Elsevier B.V. All rights reserved.