Electron beam irradiation of polytetrafluoroethylene in air: investigations on the thermal behaviour

The influences of annealing on electron beam irradiated polytetrafluoroethy lene (PTFE) powder were studied. The onset of thermal degradation is shifte d to higher temperatures in comparison to unannealed PTFE as followed close ly by thermogravimetry. Above 225 degrees C radiation-induced peroxy radica ls are converted to alkyl radicals in a partially reversible process. Simul taneous thermal analyses indicated a release of oxygen containing groups at temperatures distinctly below the degradation temperature of the backbone chains. The behaviour of the carbonyl fluoride and carboxyl groups during a nnealing in moist air, oxygen atmosphere, and vacuum was monitored by IR sp ectroscopy. (C) 1999 Elsevier Science B.V. All rights reserved.