Vinylidene fluoride copolymerization

Vinylidene fluoride copolymerized with other fluorinated monomers to give a polymer with higher fluorine content and increased flexibility Crystalline but less so than the homopolymer 5.92... 

The most chemical-resistant plastic commercially available today is tetrafluoroethylene or TFE (Teflon). This thermoplastic is practically unaffected by all alkahes and acids except fluorine and chlorine gas at elevated temperatures and molten metals. It retains its properties up to 260°C (500°F). Chlorotrifluoroethylene or CTFE (Kel-F, Plaskon) also possesses excellent corrosion resistance to almost all acids and alkalies up to 180°C (350°F). A Teflon derivative has been developed from the copolymerization of tetrafluoroethylene and hexafluoropropylene. This resin, FEP, has similar properties to TFE except that it is not recommended for continuous exposures at temperatures above 200°C (400°F). Also, FEP can be extruded on conventional extrusion equipment, while TFE parts must be made by comphcated powder-metallurgy techniques. Another version is poly-vinylidene fluoride, or PVF2 (Kynar), which has excellent resistance to alkahes and acids to 150°C (300°F). It can be extruded. A more recent development is a copolymer of CTFE and ethylene (Halar). This material has excellent resistance to strong inorganic acids, bases, and salts up to 150°C. It also can be extruded. 

PDD as well as other dioxoles have been copolymerized with monomers such as vinyl fluoride, vinylidene fluoride, tiifluoroediylene, perfluoroalkylethylenes, chlorotrifluoroethylene, hexafluoropropylene, and perfluorovinyl ethers, some of which contain functional groups. 

PDD readily copolymerizes with tetrafluoroethylene and other monomers containing fluorine, such as vinylidene fluoride (VDF), chlorotrifluoroethylene (CTFE), vinyl fluoride (VF), and propylvinyl ether (PVE) via free radical copolymerization, which can be carried out in either aqueous or nonaqueous media. It also forms an amorphous homopolymer with a Tg of 335°C (635°F) [2]. 

The matter of the head-to-head, tail-to-tail polymerization of vinyl fluoride, vinylidene fluoride, and trifluoroethylene and the copolymerization of vinyl fluoride with vinylidene chlorofluoride and l-chloro-2-fluoroethylene has been extensively studied by Cais and Kometani [24-27] and by Bruch, Bovey, and Cais [28]. The synthesis of pure head-to-tail poly(trifluoroethylenes) is described in Ref. [25]. Isomers of poly(vinyl fluoride) with controlled regiosequence microstructure are discussed in Ref. [27]. 

AHM Ahmed, T.S., DeSimone, J.M., and Roberts, G.W., Copolymerization of vinylidene fluoride with hexafluoropropylene in supercritical carbon dioxide. Macromolecules, 39, 15, 2006. 

PVDF film, as produced from the melt, is largely in the nonpolar a-form, the fS phase only being obtained after subsequent processing operations, as described above. If however, vinylidene fluoride is copolymerized with as little as 7% by weight of trifluoroethylene, a copolymer is formed with crystallites completely in the / -form. This obviates the need for stretching after synthesis and the copolymer can be processed byway conventional routes, such as injection molding. Moreover, unlike PVDF, copolymers of vinylidene fluoride and trifluoroethylene have been shown to demonstrate the ferroelectric to paraelectric transition. For a copolymer with a composition of 55% vinylidene fluoride and 45% trifluoroethylene, a phase transition is observed near 70°C, and with 90% vinylidene difluoride, a phase transition at 130°C. 

Kaur, S., Ma, Z., Gopal, R., Singh, G., Ramakrishna, S. and Matsuura, T. 2007. Plasma-induced graft copolymerization of poly(methacrylic acid) on electrospun poly(vinylidene fluoride) nanofiber membrane, 23 13085-13092. 

Nasef, M.M., Saidi, H. and Dahlan, K.Z.M. 2011. Kinetic investigation of Graft copolymerization of sodium styrene sulfonate onto poly(vinylidene fluoride) films. 

Dimethyl [2-(methactyloylo qr)ethyl]phosphonate (MAPC2) (Scheme lO.l) has been successfully copolymerized with methyl methacrylate (MMA) and used as an additive with poly(vinylidene fluoride) [poly(VDF)]. The incorporation of a phosphonic component results in a copolymer with highly... 

The copolymerization reactions of vinylidene fluoride and hexafluoropropylene were carried out in the presence of an organic mono-iodide compound, (CF3)2CFI, or di-iodide-compounds, I (CF2)4l, I(CF2)6l> as chain transfer agents and the following results were obtained. 

PropGrtiBS. PDD is a colorless liquid with the boiling point of 33°C (3). It is very reactive and can homopolymerize, and therefore, needs to he stored at low temperature with a small amount of free-radical inhibitor. PDD can copolymerize with tetrafluoroethylene or other fluorinated monomers, such as vinylidene fluoride, vinyl fluoride, or chlorotrifluoroethylene. 

Copolymers of VF with vinylidene fluoride [75-38-7] and tetrafluoroethylene [116-14-3] also have been prepared with this initiation system. VF tends toward alternation with tetrafluoroethylene and incorporates preferentially in copolymerization with vinylidene fluoride [see Perfluorinated Polymers, Polytetrafluoroethylene Vinylidene Fluoride Polymers]. 

A combination of gas chromatography and either electron-impact or chemical ionization mass spectrometry has been used to analyse the products of thermal degradation of poly(vinyl fluoride) and of a number of other polymers [poly(vinyl chloride), aromatic polyimides, polyurethane]. The degradation of poly(vinyl-idene fluoride) has been related to its crystalline form. It is claimed that dehydrofluorination may take place preferentially in crystalline segments containing trans sequences. Thermo-oxidative breakdown is modified if vinylidene fluoride is copolymerized with tetrafluoroethylene or hexafluoroacetone. Dehydrofluorination occurred in both copolymers, but in the latter it was preceded by cleavage of the H from the CHj group in the alpha position to the ether bond followed by scission of the C-0 bond. ... 

However, the curiosity-motivated research on fluoro-oleftn polymers was well rewarded and a variety of novel products tumbled out. First came plastic polyvinyl fluoride and polyvinylidene fluoride each of which had remarkable physical properties. Then Tom Ford discovered that flexible but leathery products were produced when he copolymerized vinylidene fluoride with some unsaturated monomers[3]. Hanford and Roland discovered that a copolymer of propylene with tetrafluoroethylene was rubbery and even recommended that it be cured with radiation or peroxide (Figure 2). About the same time 1 found that plastic polyethylene could be changed to a limp rubbery material by attachment of as little as 5 mol percent of trifluoromethylethylene (Figure 3)[5]. However, with the urgent pressures of the war, there wasn t enough manpower to pursue these leads. Then in the press of the post World War II industrial boom these developments were put aside. There were just too many ripe apples on the tree. 

In the addition to homo-PVF2, a large number of copolymers have also been synthesized which allow to optimize the mechanical properties of fluoropolymers. Most common are copolymers with vinyl fluoride, trifluoroethylene, tetrafluoroethylene, hexafiuoropropy-lene, hexafluoroisobutylene, chlorotrifluoroethylene, and pentafiuoro-propene [521,535, 559-562]. Copolymerization with nonfluorinated monomers is possible [563] in principle but has not yet found commercial use. Fluorocarbon monomers that can help to retain or enhance the desirable thermal, chemical, and mechanical properties of the vinylidene structure are more interesting comonomers. Copolymerization with hexafluoropropylene, pentafluoropropylene, and chlorotrifluoroethylene results in elastomeric copolymers [564]. The polymerization conditions are similar to those of homopoly(vinylidene fluoride) [564]. The copolymers have been well characterized by x-ray analysis [535], DSC measurements [565], and NMR spectroscopy [565,566]. 

Apart from the fluoro monomers vinyl fluoride (VF), vinylidene fluoride (VF2), and tetrafluoroethylene (TFE), only chlorofluoroethylene has found commercial use as homopolymer. It is applied as thermoplastic resin based on its vapor-barrier properties, superior thermal stability (Tdec > 350 °C), and resistance to strong oxidizing agents [601]. Chlorofluoroethylene is homo- and copolymerized by free-radical-initiated polymerization in bulk [602], suspension, or aqueous emulsion using organic and water-soluble initiators [603,604] or ionizing radiation [605], and in solution [606]. For bulk polymerization, trichloroacetyl peroxide [607] and other fluorochloro peroxides [608,609] have been used as initiators. Redox initiator systems are described for the aqueous suspension polymerization [603,604]. The emulsion polymerization needs fluorocarbon and chlorofluorocarbon emulsifiers [610]. 

Oils and waxes with excellent chemical inertness are obtained from low-molar-mass poly(chlorotrifluoroethylene). They are prepared by polymerization of the monomer in the presence of suitable chain transfer agents [601]. Furthermore, chlorotrifluoroethylene has been copolymerized with vinylidene fluoride to elastomeric polymers by suspension and emulsion polymerization [601,611]. 

Most of the other fluorine-containing monomers such as trifluoroethylene, hexafluoropropylene, and pentafluoropropylene are used only for copolymerization with vinyl fluoride, vinylidene fluoride, and tetrafluoroethylene [506,521,535,559-562]. Those copolymers, after a convenient vulcanization procedure using peroxides, diisocyanates, or amines, can be applied as fluorocarbon elastomers [564]. Due to the fluorine content, they have high chemical resistance and often a broad temperature range for application [612]. Polymers of interest are the vinylidenefluoride/hexafluoropropylene copolymer and the... 

SCHEME 8.1 Schematic illustration of the processes of thermally induced graft copolymerization of NIPAM from the ozone-preactivated PVDF backbone and the preparation of the PVDF-g-PNIPAM microporous membrane by phase inversion. PVDF, poly(vinylidene fluoride) NIPAM, V-isopropylacrylamide. Reprinted with permission from Reference 63. Copyright 2002 American Chemical Society. 

SCHEME 8.4 Schematic illustration of the processes involved in the graft copolymerization of DMAEMA from PVDF main chains via AGET-ATRP, preparation of PVDF-g-PDMAEMA membrane by phase inversion, and quaternization of PVDF-g-PDMAEMA membrane by propargyl bromide to produce PVDF-g-PQDMAEMA membrane with pendant aUcyne groups, covalent immobilization of hyperbranched polymer HPG-Nj or PEI-Nj onto the PVDF-g-PQDMAEMA membrane surface via surface alkyne-azide click reaction. PVDF, poly(vinylidene fluoride) DMAEMA, 2-(V, V-dimethylamino)ethyl methacrylate VC = L-ascorbic acid PMDETA = V,V,M,V, A"-pentamethyl diethylene triamine HPG-N3 = az/hyperbranched polyglycerols PEI-N3 = azirfo-polyethylenimine. Reprinted with permission from Reference 114. Copyright 2013 American Chemical Society. 

SCHEME 8.7 Schematic illustration of the process of ozone prelrealment, graft copolymerization PVDF with PMA, preparation of PVDF-g-PPMA membrane with clickable surface by phase inversion, preparation of functional PVDF-g-P[PMA-cZ/ck-MPS] membranes via surface thiol-yne click reaction of thiols on the PVDF-g-PPMA membrane, and preparation of PVDF-g-P[PMA-c//ck-P-CD] membranes via surface alkyne-azide click reaction on the PVDF-g-PPMA membranes. PVDF, poly(vinylidene fluoride) PMA, propargyl methacrylate MPS, 3-mercapto-l-propanesulfonic acid sodium salt azido-fl-CD, mono(6-azido-6-desoxy)-P-cyclodexIrin. Reprinted with permission from Reference 168. Copyright 2011 American Chemical Society. 

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