A Fluorine-19 NMR Study of the Microstructure of Vinylidene Fluoride–Trifluoroethylene Copolymers

Abstract

ABSTRACT:Copolymers ofvinylidene fluoride (VDF) and trifluoroethylene (TRFE) covering the whole range of copolymer compositions were prepared by the bulk-polymerization method using a peroxide as initiator. The monomer reactivity ratios were r A (VDF)= 0. 7 and r8 (TRFE)=0.5. The microstructure of the copolymers was examined by high-resolution 19 F NMR. The normalized monomer-diad and -triad fractions as a function of polymer composition were obtained from NMR line-intensity relationships and numerical calculations using the comonomer-sequence distribution theory suggested by Ito and Yamashita. It was found that the VDF-TRFE copolymer has a statistically random configuration, and the head-to-tail structures ofVDF-TRFE or TRFE-VDF sequences are predominant.

Synthesis and polymerization of fluorinated monomers bearing a reactive lateral group?part 7. Copolymerization of tetrafluoroethylene with ?-hydroxy trifluorovinyl monomers

“…57 In contrast to Ito and Yamashita, 56 who treated three models, we have selected the simplest one (i.e., the terminal model). This theory was successfully applied by Yagi and Tatemoto 58 for the copolymerization of vinylidene fluoride with trifluoroethylene. Two independant conditions of probability can be kinetically written as follows: The fractions of monomer diads F AA , F AB , F BA , and F BB can be calculated by the following equations:…”

Transitions and Relaxations in Poly(trifluoroethylene)

“…The 19 F NMR results 5 indicate that the abnormal head-to-head, and tail-to-tail, and tail-tohead linkages are predominant in P3FE molecule. It is considered that these defects remain in crystal lattice as holes, since t-he van der Waals radius of fluorine is larger to some extent than that of hydrogen, and the C-F bond distance is also to a certain degree longer than the C-H bond distance.…”

Energy storage study of ferroelectric poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) terpolymers

“…0.4 mmol of oxygen was introduced into the autoclave to oxidize organoborane and initiate polymerization before the mixture was warmed to ambient temperature and stirred for 5 h. The resulting polymer was obtained by removing solvent under vacuum, subsequently purified by precipitating from the polymer solution in acetone with excess hexane and washing 3 more times with hexane, and finally dried in a vacuum oven at 70 C for 8 h. The 1 H NMR (in acetone-d 6 ) was used to identify the structure of P(VDF-CTFE) as follows: 6.1-6.5 (t, 1H, -CH 2 CF 2 H), 2.6-3.6 (m, 2H, -CF 2 CH 2 CF 2 -), 2.2-2.5 (m, 2H, -CF 2 CH 2 CH 2 CF 2 -), 1.8 (t, 3H, -CF 2 CH 3 ), 1.3-1.6 (m, 2H, -CF 2 CH 2 CH 2 CH 3 ), 0.9-1.1 (t, 3H, -CF 2 CH 2 CH 2 CH 3 ). The P(VDF-CTFE)s composition could be conveniently calculated from 19 F NMR according to the method described in literature [13].…”

“…In order to keep the polymers with well-controlled composition and distribution, the monomer conversions of all the copolymerization have been carefully controlled in 30-40% via altering the reaction time as shown in Table 1 from B-1 to B-9. All the conversions of terpolymers (C-1 to C-2) are controlled in 20-30% because of the bigger reactivity ratio difference of VDF and TrFE [19]. Via controlling the hydrogenation reaction, two series of terpolymers with about 8% and 4% of CTFE and variable content of TrFE from 5.2-33.5% were prepared and are listed in Table 2.…”