Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
-rays radiation-induced homopolymerization of trifluorovinyl heptafluoropropyl etherNarita, Tadashi*; Enomoto, Kazuyuki*; Maekawa, Yasunari; Yoshida, Masaru; Ichikawa, Mitsuru*; Hamana, Hiroshi*
Journal of Fluorine Chemistry, 128(1), p.52 - 54, 2007/01
Times Cited Count：5 Percentile：19.89(Chemistry, Inorganic & Nuclear)Perfluorinated polymers have expected to be the key materials for fuel cell membranes owing to the high chemical stability, thermo-durability and optical property. However, a homopolymer of FVPE has never yielded under usual polymerization conditions and alternating copolymers with several non-fluorinated vinyl monomers have only been reported. Thus, using radiation-induced polymerization, in which initiating species (radicals) can be continuously produced, the polymerization of trifluorovinyl heptafluoropropyl ether (FVPE) was examined to afford high molecular weight polymers of FVPE. The formation of FVPE homopolymers was confirmed by NMR and IR spectroscopy.
-trifluoromethyl-
, -difluorovinyl) terephthalate with excess of various ethersEnomoto, Kazuyuki*; Maekawa, Yasunari; Katsumura, Yosuke*; Miyazaki, Toyoaki*; Yoshida, Masaru; Hamana, Hiroshi*; Narita, Tadashi*
Macromolecules, 38(23), p.9584 - 9593, 2005/11
Times Cited Count：9 Percentile：30.73(Polymer Science)Radiation-induced radical polyaddition of bis(-trifluoromethyl-,-difluorovinyl) terephthalate [CF
=C(CF3)OCOC
H
COOC(CF
)=CF] (BFP) in the presence of an excess of cyclic and acyclic ethers in feed was examined at 0
C using -rays irradiation. Irradiation of BFP with an 8-fold excess of 1,4-dioxane (DOX) and diethyl ether (EE) gave monomodal polymers consisting of the 
ernating unit of BFP and DOX moieties (poly(BFP--DOX), 
= 5.1
10
) and of BFP and EE (poly(BFP--EE), =3.910), respectively. The irradiation of BFP with an 8-fold excess of tetrahydrofuran or tetrahydropyran provided only 1:2 addition products in high yields. Mono-functional 2-benzoxypentafluoropropene [CF=C(CF)OCOCH
] (BPFP) as a model compound showed preferential formation of the 2:1 adduct to the 1:1 adduct with DOX and EE. The kinetic analysis of the model reactions revealed that the rate constants for the formation of the 2:1 adducts (
) of BPFP with DOX and EE were two orders of magnitude higher than those of the 1:1 adducts (
). Poly(BFP--DOX) showed higher radiation resistance than poly(BFP--EE) in solid states as well as in solution. It was concluded that radiation-induced step-growth polymerization under the stoichiometric imbalance of the two compounds requires a high / value as well as high radiation resistance for the formation of high molecular weight polymers.
Enomoto, Kazuyuki*; Narita, Tadashi*; Maekawa, Yasunari; Yoshida, Masaru; Hamana, Hiroshi*
Journal of Fluorine Chemistry, 125(7), p.1153 - 1158, 2004/07
Times Cited Count：3 Percentile：10.94(Chemistry, Inorganic & Nuclear)Radical polyaddition of bis(-trifluoromethyl-,-difluorovinyl) terephthalate (BFP) with 1,4-dioxane (DOX) afforded higher molecular weight polymers under -rays compared to those yielded by benzoyl peroxide initiation. More detailed study on the radiation-induced polyaddition of BFP with DOX and optimization of the reaction conditions were carried out. It was necessary to irradiate with doses of 2000, 1500, and 750 kGy, to obtain quantitative conversion of BFP at the feed molar ratio DOX/BFP of 8.0, 16, and 32, respectively. Step-growth polymerization mechanism was suggested by the measurements of molecular weights of the polymers obtained with several irradiation doses. It was concluded that the molecular weight of the polymer could be controlled by the feed molar ratio of DOX/BFP and irradiation doses. The reaction between polymers might take place after the quantitative conversion of BFP. Radiation-induced radical polyaddition mechanism of BFP with DOX was proposed.
