Effect of temperature and a crosslinking promoter on the gamma-radiolysis of a perfluoroelastomer

Methods of promoting the radiation-induced cross linking of poly(tetrafluor o-ethylene-co-perfluoromethyl vinyl ether) (TFE/PMVE) have been investigate d. Greater control of the crosslinking and chain-scission reactions was ach ieved by varying the radiolysis temperature. This was attributed to tempera ture affecting the mobilities of reactive species such as polymeric free ra dicals. These reactive species are precursors to radiation-induced cross li nks and chain-ends. Analysis of the sol/gel behaviour, tensile properties a nd FTIR indicated that the optimum temperature for the radiation crosslinki ng of TFE/PMVE, at a dose of 150 kGy, was 263 K. This temperature was 10 K below the glass transition temperature. Incorporation of 1 wt% triallyl iso cyanurate (TAIC) greatly amplified the radiation crosslinking of TFE/PMVE, The dose for gelation was decreased by 70%, and the additive imparted super ior mechanical properties compared to the neat irradiated TFE/PMVE. Electro n spin resonance (ESR) measurements showed higher radical yields at 77 K wi th the 1 wt% TAIC, indicating that the crosslinking promoter was acting as a radical trap. (C) 1999 Society of Chemical Industry.