Thermal and mechanical properties of radiation crosslinked poly(tetrafluoroethylene-co-perfluoromethyl vinyl ether)

The gamma-radiolysis of poly(tetrafluoroethylene-co-perfluoromethyl vinyl e ther) (TFE/PMVE) was investigated using chemical and mechanical analyses. T he polymer was found to form an insoluble network with a dose of gelation o f 15.8 kGy. Tensile and glass transition temperature measurements indicated the predominance of crosslinking, with optimal elastomeric properties reac hed in the dose range of 120 to 200 kGy. Photoacoustic FTIR spectroscopy CP AS) showed the formation of new carboxylic acid end groups on irradiation. These new end groups were shown to decrease the thermal oxidative stability of the crosslinked network as determined by thermal gravimetric analysis. Electron spin resonance (ESR) studies of the polymer at 77 K indicated the presence of radical precursors. A G-value of 1.1 was determined for radical production at 77 K. Comparison of radical concentrations for a copolymer w ith a different mole ratio of PMVE, indicated that the PMVE units contribut e to scission reactions. (C) 1998 Elsevier Science Ltd. All rights reserved .