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Effect of gamma radiation on fluoropolymers

Abstract:

A series of fluoropolymer films were synthesized by reacting several bisphenol monomers with 1,3-bis(1,1,1,3,3,3-hexafluoro-2-pentafluorophenyl methoxy-2-propyl)benzene via a nucleophilic aromatic substitution to form polyethers. The bisphenols used included two diphenol-substituted spirodilactams (SDL; aliphatic and aromatic), biphenol, bisphenol A, bisphenol AF, bisphenol O, and bisphenol F to form seven different polymers. Polymers were irradiated by a Gamma beam 651-PT at a dose rate of 10,5 kGy/h; the absorbed dose in each film was varied between 300 and 1000 kGy. The effect on the chemical structure upon radiation was studied by DSC, TGA, FTIR-ATR, and NMB after and before irradiation. Thermal analysis showed a lessened thermal stability and a lower T g after irradiation. Further, irradiation caused a decrease in molecular weight as a result of cleavage of sp 3 bonds. These data allowed calculation of the radiochemical yield scission (G s) for each of these polymers. The SDL aromatic system proved the most radiation-resistant. ©2009 Wiley Periodicals, Inc.