TY - JOUR
T1 - The use of 19F NMR for new structure determination in the radiolysis of FEP
AU - Gleason, K. K.
AU - Hill, D. J.T.
AU - Lau, K. K.S.
AU - Mohajerani, S.
AU - Whittaker, A. K.
N1 - Funding Information:
The authors wish to acknowledge the financial support of the Australian Institute for Nuclear Science and Engineering and the Australian Research Council.
PY - 2001/12
Y1 - 2001/12
N2 - The radiation chemistry of poly(tetrafluoroethylene-co-perfluoropropylene), FEP, with a mole fraction of tetrafluoroethylene, TFE, of 0.90 has been studied under vacuum using 60Co γ-radiation over absorbed dose ranges up to 3.0 MGy. The radiolysis temperatures were 300, 363, 423 and 523 K. New structure formation in the copolymers was analyzed by solid-state 19F NMR. The new structures formed in the copolymers have been identified and the G-values for the formation of new -CF3 groups was 2.2 at the lower temperatures and increased to 2.9 at 523 K. The G-value for the loss of original -CF3 groups was ≈1.0 at all temperatures. At the lower temperatures there was a net loss of -CF- groups on irradiation; G(CF) of -1.3, -0.9 and -0.5 at 300, 363 and 423 K, respectively, but at 523 K there was a net gain with G(CF) equal to 0.8.
AB - The radiation chemistry of poly(tetrafluoroethylene-co-perfluoropropylene), FEP, with a mole fraction of tetrafluoroethylene, TFE, of 0.90 has been studied under vacuum using 60Co γ-radiation over absorbed dose ranges up to 3.0 MGy. The radiolysis temperatures were 300, 363, 423 and 523 K. New structure formation in the copolymers was analyzed by solid-state 19F NMR. The new structures formed in the copolymers have been identified and the G-values for the formation of new -CF3 groups was 2.2 at the lower temperatures and increased to 2.9 at 523 K. The G-value for the loss of original -CF3 groups was ≈1.0 at all temperatures. At the lower temperatures there was a net loss of -CF- groups on irradiation; G(CF) of -1.3, -0.9 and -0.5 at 300, 363 and 423 K, respectively, but at 523 K there was a net gain with G(CF) equal to 0.8.
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U2 - 10.1016/S0168-583X(01)00749-2
DO - 10.1016/S0168-583X(01)00749-2
M3 - Article
AN - SCOPUS:0035584049
SN - 0168-583X
VL - 185
SP - 83
EP - 87
JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
IS - 1-4
ER -