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

Solid-Liquid Europium Ion Extraction via Phosphonic Acid-Functionalized Polyvinylidene Fluoride Siloxanes

Novel triethoxysilane and dimethyl phosphonate functional vinylidene fluoride (VDF)-containing terpolymers, for potential applications in Eu ion extraction from water, were produced by conventional radical terpolymerization of VDF with vinyltriethoxylsilane (VTEOS) and vinyldimethylphosphonate (VDMP). Although initial attempts for the copolymerization of VTEOS and VDMP failed, the successful terpolymerization was initiated by peroxide to lead to multiple poly(VDF-ter-VDMP-ter-VTEOS) terpolymers, that had different molar percentages of VDF (70–90 mol.%), VTEOS (5–20 mol.%) and VDMP (10 mol.%) in 50–80% yields. The obtained terpolymers were characterized by ¹H, ¹⁹F, ²⁹Si and ³¹P NMR spectroscopies. The crosslinking of such resulting poly(VDF-ter-VDMP-ter-VTEOS) terpolymers was achieved by hydrolysis and condensation (sol–gel process) of the triethoxysilane groups in acidic media, to obtain a 3D network, which was analyzed by solid state ²⁹Si and ³¹P NMR spectroscopies, TGA and DSC. The thermal stability of the terpolymers was moderately high (up to 300 °C under air), whereas they display a slight increase in their crystallinity-rate from 9.7% to 12.1% after crosslinking. Finally, the dimethyl phosphonate functions were hydrolyzed into phosphonic acid successfully, and the europium ion extraction capacity of terpolymer was studied. The results demonstrated a very high removal capacity of Eu(III) ions from water, up to a total removal at low concentrations.

Cobalt-Mediated Radical Copolymerization of Chlorotrifluoroethylene and Vinyl Acetate

Controlled radical copolymerization of chlorotrifluoroethylene (CTFE) and vinyl acetate (VAc) was successfully achieved in the presence of bis(acetylacetonato)cobalt(II) (Co(acac)₂) as a mediated agent and 2,2'-azo-bis-isobutyronitrile (AIBN) as initiator. Both the molar mass and the fluorinated unit content of the copolymer could be controlled, and the chain extension polymerization of the obtained fluorinated copolymer was also achieved.

19 F DOSY diffusion-NMR spectroscopy of fluoropolymers

A new pulse sequence for obtaining ¹⁹ F detected DOSY (diffusion ordered spectroscopy) spectra of fluorinated molecules is presented and used to study fluoropolymers based on vinylidene fluoride and chlorotrifluoroethylene. The performance of ¹⁹ F DOSY NMR experiments (and in general any type of NMR experiment) on fluoropolymers creates some unique complications that very often prevent detection of important signals. Factors that create these complications include: (1) the presence of many scalar couplings among ¹ H, ¹⁹ F and ¹³ C; (2) the large magnitudes of many ¹⁹ F homonuclear couplings (especially ² J_FF ); (3) the large ¹⁹ F chemical shift range; and (4) the low solubility of these materials (which requires that experiments be performed at high temperatures). A systematic study of the various methods for collecting DOSY NMR data, and the adaptation of these methods to obtain ¹⁹ F detected DOSY data, has been performed using a mixture of low molecular weight, fluorinated model compounds. The best pulse sequences and optimal experimental conditions have been determined for obtaining ¹⁹ F DOSY spectra. The optimum pulse sequences for acquiring ¹⁹ F DOSY NMR data have been determined for various circumstances taking into account the spectral dispersion, number and magnitude of couplings present, and experimental temperature. Pulse sequences and experimental parameters for optimizing these experiments for the study of fluoropolymers have been studied. Copyright © 2016 John Wiley & Sons, Ltd.

Poly(vinylidene fluoride) Containing Phosphonic Acid as Anticorrosion Coating for Steel

Vinylidene fluoride (VDF)-based copolymers bearing pendant phosphonic acid function for potential application as anticorrosion coatings were synthesized via free radical copolymerization of VDF with a new phosphorus containing 2-trifluoromethacrylate monomer, (dimethoxyphosphoryl)methyl 2-(trifluoromethyl)acrylate (MAF-DMP). MAF-DMP was prepared from 2-trifluoromethacrylic acid in 60% overall yield. Radical copolymerizations of VDF with MAF-DMP initiated by tert-amyl peroxy-2-ethylhexanoate at varying ([VDF]₀/[MAF-DMP]₀) feed ratios led to several poly(VDF-co-MAF-DMP) copolymers having different molar percentages of VDF (79-96%) and number-average molecular weights (M_n's) up to ca. 10 000 g mol^-1 in fair yields (47-53%). Determination of the composition and microstructure of all the synthesized copolymers was done by ¹H and ¹⁹F NMR spectroscopies. The monomer reactivity ratios of this new VDF/MAF-DMP pair were also determined (r_VDF = 0.76 ± 0.34 and r_MAF-DMP = 0 at 74 °C). The resulting poly(VDF-co-MAF-DMP) copolymers exhibited high melting temperature (162-171 °C, with respect to the VDF content), and the degree of crystallinity reached up to 51%. Finally, the pendant dimethyl phosphonate ester groups of the synthesized poly(VDF-co-MAF-DMP) copolymer were quantitatively hydrolyzed, giving rise to novel phosphonic acid-functionalized PVDF (PVDF-PA). In comparison to hydrophobic poly(VDF-co-MAF-DMP) copolymers (the water contact angle, WCA, was 98°), the hydrophilic character of the PVDF-PA was found to be surprisingly rather pronounced, exhibiting low WCA (15°). Finally, steel plates coated with PVDF-PA displayed satisfactory anticorrosion properties under simulated seawater environment.

The functionalization of fluoroelastomers: approaches, properties, and applications

This review seeks to give an overview of different approaches to prepare functional fluoroelastomers for modern industries.

Kinetic and mechanistic aspects of the iodine transfer copolymerization of vinylidene fluoride with 2,3,3,3-tetrafluoro-1-propene and functionalization into ω-hydroxy fluorinated copolymers

ω-Hydroxy functionalized poly(vinylidene fluoride) prepared in a water-based non-fluorinated solvent by iodine transfer copolymerization VDF and 1234yf.

Synthesis and properties of a well-defined copolymer of chlorotrifluoroethylene and N-vinylpyrrolidone by xanthate-mediated radical copolymerization under 60Co γ-ray irradiation

RAFT/MADIX polymerization of CTFE and NVP under ⁶⁰Co γ-ray irradiation with S-benzyl O-ethyl dithiocarbonate (BEDTC).