Polyvinylidene fluoride coatings

Modification of alkyd resins with high proportions of silicones considerably reduces rates of attack, but the most spectacular extension of life is shown by fluorinated polymers such as polyvinylidene fluoride where erosion rates can be reduced to 0 -1 /tm/year. If this level of durability can be achieved an initial coating, if firmly adherent and free from any breaks, may often be expected to maintain protection over a metal substrate for the likely life of the structure. The considerably increased first cost, as compared with more conventional coatings, has to be balanced against the probable saving in maintenance costs or consequences of failure. 

P.V.D.F. Polyvinylidene fluoride (p.v.d.f. or p.v.f.2) dispersions are applied by the coil-coating process. They are blends of p.v.d.f. resin and acrylic. The combination produces a system which has excellent weather-ability and which can be bonded via an adhesive primer to a galvanised steel or aluminium substrate. 

Coating of ultrafiltration/microfiltration membrane supports such as polyvinylidene fluoride (PVDF) or polysulfone (PSF) with solutions of polymers such as poly(ether-hlocfc-amide) [51]. 

Hydrogen fluoride can be handled in apparatus of suitable metals (copper, nickel, magnesium, or aluminum, which all form a protective fluoride coating, or platinum), or plastic materials [especially polypropylene. Teflon, and polyvinylidene fluoride (Viton)] polychlorotrifluoroethylene (Kel-F) can be made into transparent windows. A capillary for a dropping mercury electrode may be made from Teflon [307]. Hydrogen fluoride is obtained commercially in steel cylinders in a purity of 99.5%. The impurities may be removed by distillation [308] or electrolysis [309]. During the electrolytic removal of water the explosive FoO is formed, which must be taken into consideration [305]. 

In this section, examples of films made from polyvinylidene fluoride (PVDF) are discussed. Although most of the pol5winylidene fluoride film is in the form of coating on metal substrates, stand-alone PVDF films and sheets are produced by extrusion and film blowing.1 ] ] Blends of PVDF and a number of other polymers such as polymethylmethacrylate (PMMA) are miscible. Films made from these blends have excellent piezoelectric properties. 

Polymeric membranes are monolithic, continuously porous materials. Membranes can be produced from numerous organic polymers including polyalkanes (polyethylene and polypropylene) and their fluorinated derivatives [polyvinylidene fluoride and polytetrafluoroethylene (PTFE)]. Once formed, a membrane can be chemically functionalized by a number of methods including direct conversion of functional groups in the bulk polymer, coating of the surface with a preformed polymer, or graft copolymerization of reactive monomers onto the membrane surface. 

All immunoassays require the use of a supporting material to immobilize either the antibody or the antigen, depending on the assay design. The most common platform is the polystyrene 96-well microtiter plate. There are other types of supporting materials, such as nitrocellulose or polyvinylidene fluoride (PVDF) membranes or gold-coated chips. The use of ELIS A has commonly been associated with the use of microtiter plates. 

Figure 4.6 Optical microscope pictures, a) to i), of the Petri plates after 4 h of yeast incubation. The bottom of each plate was either coated with the bare polyvinylmethyl ketone (PVMK), polyvinyl chloride (PVC) and polyvinylidene fluoride (PVDF) polymers or by polymer-tetrabutylammonium perchlorate (TBAP) films or by the copper NP-PVMK, copper NP-PVC, and copper NP-PVDF nanocomposites. Reproduced with permission from N. Cioffi, L. Torsi,...

The laminate sheet is a flexible decorative sheet for use in surfacing an automobile body panel. The laminate revealed in this invention contains several layers, including clearcoat, tie coat, color coat, and adhesive layer. Clearcoat is formulated from polyvinylidene fluoride (to assure excellent weather resistance), tie coat is formulated from acrylic (good adhesion to both clear coat and color coat and weather resistance), color coat was formulated from PVC (see formulation in the above table) and adhesive was pressure sensitive acrylic formulation. 

Polyvinylidene Fluoride Thermoplastic polymer of vinylidene fluoride has good strength, proeessability, wear, fire, solvent, and creep resistance, and weatherability, but decreased dielectric properties and heat resistance. Processed by injection and transfer molding, extrusion, and powder coating. Used in electrical insulation, pipes, chemical apparatus, coatings, films, containers, and fibers. Also called PVDF. 

For areas with special application requirements, specifically modified polyester fabrics, as well as fabrics from aramid fibres, fluorine polymers and arylamides like Kevlar (ref. DuPont), have proved to be satisfactory. The membranes show different characteristics depending on the coatings used. Fluorine polymers such as PVDF (polyvinylidene fluoride) are used on PES fabrics (refs Mehler and Ferrari) a PTFE (polytetrafluoroethylene) coating is very suitable for fibreglass fabrics (ref Verseidag) and there is a newly developed composite membrane with THV (ret Dyneon), a polymeric blend of tetrafluoroethylene, hexafluoropropylene and vinylidenefluorine, used as a coating on PES fabrics, of which VALMEX vivax (ret Mehler) is one example. 

Biphenylcarboxaldehyde Chlorodiphenyl (54% Cl) 2-Ethylhexyl methacrylate Maleic acid/acrylic acid copolymer Maleic acid/olefin copolymer, sodium salt paints/coatings, UV light-resistant Polyvinylidene fluoride resin paints/coatings, weathering-resistant Polyvinylidene fluoride resin pallet wrapping Polyethylene, low-density palliative, skin care Aloe... 

The coating speed lies preferably within the range from 30 to 120 m/min, and the coating thickness between 15 and 150 p.m depending on the type of coating and its thickness. Numerous technological processes and resin compositions are used in coil coating. " Polyesters and polyvinylchloride are the most frequently used polymeric materials followed by polyvinylidene fluoride, polyurethanes, epoxy, acrylics, and polyamides. ... 

Another assay that has gained popularity and acceptance for the evaluation of permeability is the parallel artificial membrane permeability assay (PAMPA). Earlier versions of this system coated polyvinylidene fluoride (PVDF) filter plates with artificial membrane using dioleoyl-sn-glycerol-3-phosphocholine (Chen et al., 2008). Several companies attempted to develop this technology in the late 1990s with limited success (Kansy et al., 1998). These earlier versions suffered poor correlation to cell models, poor correlation to human absorption, and poor reproducibility. More modem systems have been developed with different lipid formulations and solvation techniques that seem to correlate better with Caco-2 and human data and are more reproducible (Chan et al., 2005). Some companies use the PAMPA as a tier 1 prescreen discovery... 

Binders in coatings include polyvinyl acetate and copolymers, polyvinyl butyral, polyesters, acrylic polymers, epoxies and polyurethanes (see Ethylene-vinyl acetate copolymers. Acrylic adhesives, Epoxide adhesives and Polyurethane), polyvinyl chloride, polyvinylidene fluoride and aUcyds (oxygen-convertible media containing polyol esters of long-chain unsaturated acids). All these potential film-formers can adhere through dispersion forces, (which are probably weak). Many binders, however, also contain... 

The solvents used in coatings are hydrocarbons for alkyds, and aromatics in admixture with more polar solvents for most other media. Highly insoluble polymers, such as polyvinyl chloride and polyvinylidene fluoride, are applied as dispersions. Selection of a wrongly formulated solvent mixture may have an adverse effect on the adhesion of a film, when formed af room femperafure. High boiling solvenfs, for example, can become flapped af the film-substrate interface for some considerable time and give rise to a soft and poorly adherent film. 

H. Lee, M. Alcoutlabi, J.V. Watson, X. Zhang, Polyvinylidene fluoride-co-chlorotriflu-oroethylene and polyvinylidene fluoride-co-hexafluoropropylene nanoflber-coated polypropylene microporous battery separator membranes. Journal of Polymer Science, Part B Polymer Physics 51 (5) (2013) 349-357. 

Positive electrode materials are generally mixed with a conductive carbon powder and a polymer binder. Commonly used binders are polyvinylidene fluoride (PVDF) and a PVDF copolymer with hexafluorpropylene (PVDF-HFP). The positive electrode mix is coated as a slurry onto a thin aluminum foil current collector while the carbon negative electrode material, often using the same binders, is coated onto a thin copper foil current collector. 

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