Electron beam irradiation of polytetrafluoroethylene in vacuum at elevatedtemperature: An infrared spectroscopic study

Electron beam irradiation of polytetrafluoroethylene (PTFE) has been per fo rmed in vacuum both at elevated temperature above the melting point of PTFE and at room temperature for comparison. The changes in the chemical struct ure were studied by Fourier-transform infrared (FTIR) spectroscopy. The for mation of double bonds in PTFE was confirmed as a result of irradiation in vacuum. Moreover, trifluoromethyl (CF3) branches were detected. The concent ration of CF3 branches was found to be much higher in irradiation at elevat ed temperature than in room temperature irradiation. The CF3 branches are a ssumed to cause the reduced crystallinity indicated by the transparency of PTFE specimens irradiated in the molten state. (C) 1999 John Wiley & Sons, Inc.