Radical Copolymerization of α,β-Difluoroacrylic Acid with Vinylidene Fluoride.

Abstract

The synthesis of R,β-difluoroacrylic acid (FHCdCF-CO 2 H, DiFAA) and its radical copolymerization with vinylidene fluoride (CH 2 dCF 2 , VDF) are presented. First, DiFAA was synthesized in three steps from the radical addition of methanol onto 1,2-dichloro-1,2-difluoroethylene leading to HCFClCFClCH 2 OH in 78% yield. Then, oxidation of the hydroxymethyl end-group followed by zincmediated dehalogenation of 2,3-dichloro-2,3-difluoropropanoic acid led to (Z) isomer of DiFAA in 29% overall yield. The homopolymerization of DiFAA was successfully achieved by radical polymerization initiated by tert-butylperoxypivalate (TBPPi) at 74 °C in 32% yield. Its radical copolymerization with VDF was carried out for the first time and at various compositions leading to functional poly(VDF). The resulting poly(VDF-co-DiFAA) copolymers, characterized by 1 H and 19 F NMR spectroscopies, exhibited a statistic microstructure. The kinetics of this radical copolymerization led to the assessment of the reactivity ratios (r DiFAA = 0.86 and r VDF = 0.34 at 74 °C), and showed that DiFAA was more reactive than VDF in copolymerization. Thermal properties of these poly(DiFAA-co-VDF) copolymers were also investigated. Differential scanning calorimetry analyses showed a decrease of the glass transition temperature (T g ) with increasing VDF content. Calculations using the Fox's equation led to the determination of the T g for poly(DiFAA) homopolymer (T g = 145 °C) in good agreement with the literature. Thermogravimetric analyses displayed increased thermostability of the resulting copolymers with increasing VDF content.

19F DOSY diffusion‐NMR spectroscopy of fluoropolymers

“…[38] Poly(VDF-co-DFAA) copolymer has been investigated for its potential to provide functionalized poly(VDF) polymers. [44] NMR parameters such as DOSY diffusion coefficients, obtained from polymers, represent the statistical average from a distribution of molecules having different molecular weights. When these parameters are measured using the polymer chain-end resonances they are determined by the number average molecular weight (M n ).…”

“…[44] It is of interest as a means of preparing functionalized VDF-based elastomers, and graft copolymers. The copolymerization proceeds in a manner similar to that of CTFE with VDC described above.…”

Photocatalytic activity of vinylidene fluoride-containing copolymers/anatase titanium oxide/silica nanocomposites

“…(Osaka, Japan). Vinylidene fluoride (VDF) copolymers, poly(VDF-co-CF 2 CFCO 2 CH 3 ) 37 , poly(VDF-co-CFHCFCO 2 H) 38 , and poly(VDF-co-CF 2 CF(CH 2 ) 3 OCOCH 3 ) 39…”

“…The radical copolymerizations of vinylidene fluoride (VDF) with various functional comonomers, F 2 C=CFCO 2 CH 3 , FCH=CFCO 2 H, and F 2 C=CF(CH 2 ) 3 OCOCH 3 were initiated by t-butyl peroxypivalate at 70 °C, and led to statistical poly(VDF-co-CF 2 CFCO 2 CH 3 ) 37 , poly(VDF-co-FCHCFCO 2 H) 38 , and poly(VDF-co-CF 2 CFC 3 H 6 OCOCH 3 ) copolymers 39 in satisfactory yields (> 60 %) (Scheme 1). of poly(VDF-co-CF 2 CFC 3 H 6 OCOCH 3 ) copolymer that exhibits the expected signals centered at -92, -113 and -116, and -110 ppm attributed to difluoromethylene groups in head-to-tail and head-to-head VDF-VDF dyads, [37][38][39] and to alternated VDF-trifluoropentenyl acetate (FAc) dyad, 39 respectively, and to those assigned to CF 2 or CF on FAc functional comonomers (Figure 1). The ratios of the integrals of the signals corresponding to both comonomers enabled to determine the molar percentages of these fluorinated comonomers in each VDF-containing copolymer.…”

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer/anatase titanium oxide nanocomposites possessing photocatalytic activity even after calcination at 1000°C

“…Furthermore, we have prepared vinylidene fluoride copolymer/ an-TiO 2 nanocomposites [-(CH 2 CF 2 ) x -(CHFCFCOOH) y -/an-TiO 2 ] possessing no silica source according to the preparative method shown in Scheme 1 (see Supporting Scheme 1). The parent fluorinated copolymer has been prepared based on the previously reported method [12]. An-TiO 2 in the nanocomposites was found to exhibit a complete phase transformation to rutile after calcination at 1000°C (see Supporting Fig.…”