Polyvinyl phosphorate

Lee [3] prepared organic anti-reflective polymer coatings consisting of polyvinyl phosphoric acid and poly(vinyl acetate-co-ethylene). 

Etch primers are widely used. They are mostly based on polyvinyl butyral and contain chromates and phosphoric acid. They are said to act both as primers and as etching solutions because it is believed that the chromates and phosphoric acid form an inorganic him, which provides adhesion, while oxidised polyvinyl butyral provides an organic him. For direct application to new galvanised steel, the best known primers are based on calcium orthoplumbate pigment and metallic lead, but these are now less used for environmental reasons. Zinc-dust paints and zinc-phosphate pigmented paints are also used, but the trend is to use pretreatments to assure good adhesion. 

A characteristic of the group (a) of resins is that they air-dry solely by solvent evaporation and remain permanently solvent soluble. This fact, combined with the need to use strong solvents, makes brush application very difficult, but sprayed coats can be applied at intervals of one hour. A full vinyl system such as (o) possesses excellent chemical and water resistance. Many members of group (o) have very poor adhesion to metal, and have therefore been exploited as strip lacquers for temporary protection. Excellent adhesion is, however, obtained by initial application of an etching primer the best known of such primers comprises polyvinyl butyral, zinc tetroxy-chromate and phosphoric acid. 

Etch primers partially fulfil the roles of both pretreatment and primer. They contain phosphoric acid for surface passivation and are based on polyvinyl butyral ... 

The standard etch primer (WP-1, DEF-1408) consists of two solutions, one containing polyvinyl butyral resin and zinc tetroxychromate in ethyl alcohol with n-butanol, and the second containing phosphoric acid and ethyl alcohol. It is essential that a small critical amount of water be present in the latter. The two solutions are mixed in appropriate ratio for use the mixture deteriorates and should be discarded when more than 8 h old. Single-pack etch primers of reasonable shelf life are available but contain less phosphoric acid than the above and are not considered to be so effective. 

The heat exchanger fins from aluminum or its alloy are coated with aqueous solution containing a water-soluble cellulose resin or polyvinyl alcohol and a surfactant to form a hydrophilic film. Phosphoric acid ester was used as anionic surfactant (0.05-4.5%) in aqueous solution to form a hydrophilic film showing contact angle with water of 5-32° [288]. 

Screen Preparations, 100 micron thick x-ray intensifying screens were prepared using standard doctor blade coating techniques. The final phosphor volume was 50% when the coatings were dried. In most instances, the phosphor suspensions were prepared using polyvinyl butyral binders with viscosities adjusted to 2000 centipoise for the doctor blade operation and care was taken to avoid convection cell formation (9). A cross section of the screen construction is shown in Figure I. The completed screens consist of polyester (Mylar) base about 10 mil. thick, a 50 micron thick (TI02 (rutile) reflector layer, a 100 micron thick phosphor layer, a 10 micron thick clear cellulose acetate butyrate top protective layer. 

Finally, the water-soluble polyesters of phosphoric or boric acid with glycols or glycerol should be mentioned. They can be used in combination with water-soluble polymers like polyvinyl alcohol, polyacrylamide, and polyvinyl pyrrolidone. 

Chlorinated polyether can be used continuously up to 125°C, intermittently up to 150°C. Chemical resistance is between polyvinyl chloride and the fluorocarbons. Dilute acids, alkalies, and salts have no effect. Hydrochloric, hydrofluoric, and phosphoric acids can be handled at all concentrations up to 105°C. Sulfuric acid over 60 percent and nitric over 25 percent cause degradation, as do aromatics and ketones. 

Phosphorous acid, H3PO3, is generated by hydrolysis of PCI3 - industrially this is carried out by spraying the chloride into steam at 190 °C. Esters of the acid, both the triaUcyl esters [P(OR)3] and the diaUcyl esters [(RO)2P(0)H], can be produced directly by substituting the appropriate acid for the water. The esters find much use thus, triphenyl phosphite is most widely used in the manufacture of polyvinyl chloride, while trinonylphenyl phosphite is an excellent stabilizer for the same polymer. 

Use Flameproofing of textiles, paper, and plastics (chiefly polyvinyl chloride) paint pigments ceramic opacifier catalyst intermediate staining iron and copper phosphors mordant glass decolorizer. 

FIGURE 10.9 Flowsheet for the Haifa (Israel Mining Industries) hydrochloric acid acidula-tion route to phosphoric acid. Digestion for a short time is followed by solvent extraction in polyvinyl-chloride mixer settlers, which tolerate the corrosive conditions. (Reprinted from Chemical Engineering (NX) [64] by special permission from the journal and McGrawHill Inc.)... 

Inhibition of animal cell cultures by ammonia has been overcome by either passing oxygen through a porous poly(tetrafluoroethylene) membrane into the culture or by continuous removal through a membrane of the same material (0.2-Jum pores) to aqueous phosphoric acid on the other side.245 Urea was removed by an anion-exchange membrane clamped over an insolubilized polyvinyl alcohol membrane containing urease.246 No ammonium ion returned back into the feed solution. A urease in poly(ethy-lene-co-vinyl acetate) converted urea on one side to ammonia for recovery on the other.247... 

During a repair, the damaged area is sanded down to bare metal and filled as necessary. An etch primer is often used to enable the VR coating to adhere to the surface of the metal. This is a very low solids coating which is applied at a low film thickness. Etch primers typically contain phosphoric acid and zinc chromate (although chromates are becoming unpopular for toxicity reasons), a binder (such as polyvinyl butyral) and a solvent system (usually based on ethanol, butanol and water). 

Poly(vinyl alcohol) can be wholly or partially converted to poly(vinyl phosphate) by the action of POCI3 followed by hydrolysis (12.82). Heating of the polyacid product leads to a cross-linked polymer which resists hydrolysis by dilute acids and bases. The monoammonium salt is obtained by the action of phosphoric acid and urea on polyvinyl alcohol (12.83). 

Plasticizers are most commonly liquid esters of low volatUity, which are blended into rigid thermoplastic polymers to make them soft and flexible. Most are esters of phthatic, phosphoric, and adipic acids. Major use is in polyvinyl chloride (PVC) elastoplastics. Another major use, rarely mentioned in the literature, is the addition of hydrocarbon oils to rubber to improve processability. Plasticizers are also used to improve melt processabUity and toughness of rigid plastics such as cellulose esters and ethers, and they are used in a variety of specialized apphcations. In some cases, they perform dual functions such as thermal stabilization or flame retardance. This gives the individual processor the ability to tailor properties for each produet. 

Traditionally, etch primers have been formulated as one-pack or two-pack products, based on polyvinyl butyral resins. In the more common two-pack products, the etchant (phosphoric acid) is a separate component, which is added to the resin/solvent component immediately before use. The one-pack products contain a small amount of chromic acid and are described as reacted stable formulations. 

Plasticizers, which are added to improve the flexibility, softness and processibility of plastics, constitute a broad range of chemically and thermally stable products of a variety of chemical classes. Their principal use is in thermoplastic resins, and 80-85% of the world s production of plasticizers are used in polyvinyl chloride (PVC) manufacturing. Approximately 450 plasticizers are commercially available. Many are esters of carboxylic acids (e.g. phthalic, isophthalic, adipic, benzoic, abietic, trimellitic, oleic, sebacic acids) or phosphoric acid. Other plasticizers are chlorinated paraffins, epoxidized vegetable oils and adipate polymers. 

Amides of organic acids are used more often than amines for the stabilization of pol3rvlnyl chloride. The patent and periodical literature pertaining to the stabilization of the vinyl chloride pol3nner and copolymers by amides, in particular, by derivatives of urea and thiourea, is presented rather fully inthe survey [154]. Of interest are the recommendations on the use of substituted amides of phosphoric [272] and stearic [273] acids as stabilizers of polyvinyl chloride. These amides contain three-membered ethyleneimine rings, which open readily when they react with HCl. 

Of the phosphorus-containing stabilizers, aromatic esters of phosphoric acid, such as tricresyl phosphate, have received the most widespread use. In many of them, stabilizing action is combined with plasticizing action. The properties of a number of esters of phosphoric acid used as stabilizers and plasticizers of polyvinyl chloride are discussed in the collection [287]. 

Two inorganic acids - phosphonic and phosphoric acid - have been in the focus of several theoretical studies in connection with fuel-cell membranes. Phosphoric acid is used as a proton-conducting electrolyte, whereas phosphonic acid is used as a protogenic group in proton-conducting polymers (e.g. in polyvinyl phosphonic acid). 

In [74], completely phosphoric acid-free inter-mediate-T membranes and MEAs from 1/1 (mole imidazole/mole PO3H2) blend membranes of the PBI B5 (Fig. 4.4) and the phosphonated polymer polyvinyl phosphonic acid (PVPA) S12 (Fig. 4.5) were presented and compared to PA-doped membranes and MEAs. In the MEAs, a Pt electrocatalyst was deposited onto multiwaUed carbon nanotubes (MWNT) which have previously been coated with B5. This technique has previously been used for the preparation of electrocatalysts for anion-exchange membrane fuel cells [75]. In the final step, the MWNTs were coated with a layer of S12. It turned out that these membranes and MEAs possessed much higher durabilities than membranes and MEAs which have been doped with PA, therefore opening leeway for long-lasting intermediate-T fuel cell membranes without the PA leaching problems which are always present in PA-doped intermediate-T membranes and MEAs [76]. 

Zinc tetroxychromate, or basic zinc chromate, is commonly used in the manufacture of two-package polyvinyl butyryl (PVB) wash primers. These consist of phosphoric acid and zinc tetroxychromate dispersed in a solution of PVB in alcohol. These etch primers, as they are known, are used to passivate steel, galvanized steel, and aluminium surfaces, improving the adhesion of subsequent coatings. They tend to be low in solids and are applied at fairly low film thicknesses [23]. 

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