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Chain scission and branching in irradiated poly(tetrafluoroethylene‐ co ‐hexafluoropropylene)
Author(s) -
Hill DJT,
Mohajerani S,
Whittaker AK,
Scheler U
Publication year - 2003
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1299
Subject(s) - hexafluoropropylene , tetrafluoroethylene , branching (polymer chemistry) , copolymer , radiolysis , polymer , polymer chemistry , materials science , irradiation , radiation chemistry , bond cleavage , chemistry , analytical chemistry (journal) , chemical reaction , radical , organic chemistry , catalysis , physics , nuclear physics
The radiation chemistry of poly(tetrafluoroethylene‐ co ‐hexafluoropropylene) (FEP) with a TFE mole fraction of 0.90 has been studied under vacuum using 60 Co γ‐radiation over a range of temperatures and absorbed doses. The radiolysis temperatures were 300, 363, 423, 523 and 543 K. New structure formation in the copolymers was analysed by solid‐state 19 F NMR spectroscopy. The new structures formed in the copolymers have been identified and the G ‐values for the formation of new chemical structures have been investigated at 363 and 523 K. These two temperatures are just above and just below the polymer T g and T m , respectively. At the lower temperature, there was no evidence for any chain branching and an estimate of G (S) of 1.0 was obtained. A value of G (S) of 1.3 and a minimum value of G (X) Y of 1.3 were obtained at 523 K. Copyright © 2003 Society of Chemical Industry