Paints constituents

For the above reasons, the identification of proteinaceous paint media, and in general organic paint constituents in works of art, is still considered a difficult challenge for the chemist. Summarising, one has to consider the following ... 

For the reasons discussed so far, the identification of organic paint constituents and in particular proteinaceous paint media is still a real challenge. One of the main difficulties in the protein analysis lies in the isolation of the proteins from a very heterogeneous sample. 

Crosslinked acrylic microgels in aqueous and non-aqueous media were patented as paint constituents in 1979 to improve the orientation of aluminum flake pigments, restrict the flow of the liquid coating on the substrate and restrict sagging [324]. As the patent speaks of emulsions, insolubility of the microgels and particle sizes up to 200 nm, it is questionable whether these polymers consisted of microgels only. 

REACH. In 2003 the EU Commission proposed a new chemicals policy -REACH (Registration, Evaluation, and Authorisation of Chemicals). The biocides used in AF products are still registered through the BPD, but the other paint constituents as with all other chemical constituents produced or imported > 1 ton/year on the European market will need to be partly or fully risk assessed under REACH. The legislation is expected to enter into force in 2007 (EU, 2003b). 

XRD identified FejO plus paint constituents of BaSOm TiO and ZnjCPO ) together with a less identifiable major phase (7.7A, 2.68A, 2.36a). This phase is now believed to be a member of a class of compounds referred to as the pyroaurite group. These compounds have the general formula ... 

OTHER COMMENTS used in the manufacture of aniline used as an ingredient in soaps, shoe polishes, and metal polishes used as a preservative in spray paints, constituent of floor polishes, and for refining lubricating oils used in the production of isocyanates, pesticides, rubber chemicals, and acetominophen. 

Zinc Oxide. We found that as little as 5 lb of zinc oxide per 100 gal (1 gal = 3.785 L) of paint was sufiBcient to impart acceptable early blister resistance to the paint when tested in the rain or in the tap water fog box (Table I). Higher zinc oxide levels showed no further blister-resistance improvement in this paint. Blistering in the deionized water fog box was so severe that even the HEC-thickened control had a blister rating of 4D. (The note to Table I explains the rating method used.) However, a noticeable effect occurred at zinc oxide levels of 5 lb/100 gal of paint and higher. The zinc oxide combined with the ammonia in the paint and formed a zinc ammonium complex that may ionically cross-link the carboxyl groups in the HASE thickener and other paint constituents, and thereby reduce the overall water sensitivity of the paint. 

Clays have layers of linked (Al, Si)04 tet-rahedra combined with layers of Mg(OH)2 or AI(0H)3- Clays are very important soil constituents and are used in pottery, ceramics, as rubber, paint, plastic and paper fillers, as adsorbents and in drilling muds. 

Zinc oxide or zinc white is used in paints, but more preferable, because of its better covering power, is lithopone (a mixture of zinc sulphide and barium sulphate). Both paints have the advantage over white lead that they do not blacken in air (due to hydrogen sulphide). Zinc dust and also zinc chromate are constituents of... 

Trisodium phosphate [7601-54-9] trisodium orthophosphate, Na PO, is an important constituent of hard-surface cleaners including those for ceramic, metal, or painted surfaces. It may be used with soaps, surfactants, or other alkaHes. It precipitates many heavy-metal ions but does not sequester to form soluble chelates. It is thus a precipitant builder and additionally an alkaH. 

A useful property of liquids is their ability to dissolve gases, other liquids and solids. The solutions produced may be end-products, e.g. carbonated drinks, paints, disinfectants or the process itself may serve a useful function, e.g. pickling of metals, removal of pollutant gas from air by absorption (Chapter 17), leaching of a constituent from bulk solid. Clearly a solution s properties can differ significantly from the individual constituents. Solvents are covalent compounds in which molecules are much closer together than in a gas and the intermolecular forces are therefore relatively strong. When the molecules of a covalent solute are physically and chemically similar to those of a liquid solvent the intermolecular forces of each are the same and the solute and solvent will usually mix readily with each other. The quantity of solute in solvent is often expressed as a concentration, e.g. in grams/litre. 

NaH POa is a solid water-soluble acid, and this properly finds u e (with NaHC03) in effervescent laxative (ablets and in the pH adjusimeni of boiler waters. It is also used as a mild phosphatizing agent for steel surfaces and as a constituent in (he undercoat for metal paints. 

Cleanness of the base, i.e. freedom from grease, which improves the wettability of the metal surface, and the removal of oxides, dust or loose paint, etc. already described. The closer the surfaces of paint film and metal, the more secondary valencies originating in the polar constituents of the medium are brought into play. 

Localised adhesion failure occurs most easily where broken scale or rust, or deposits of salts, have impeded wetting of the metal substrate by the film-forming constituents of the paint. 

Extender an inorganic material in powder form which has a low refractive index and consequently little obliterating power, but is used as a constituent of paints to adjust the properties of the paint, notably its working and film-forming properties and to avoid settlement on storage. 

Solvent a liquid, usually volatile, which is used in the manufacture of paint to dissolve or disperse the film-forming constituents, and which evaporates during drying and therefore does not become a part of the dried film. Solvents are used to control the consistency and character of the finish and to regulate application properties. 

Saponification deterioration by softening of paint film caused by action of aqueous alkali, resulting from cathodic protection at excessively high current densities, on the fatty-acid constituents of the film. 

Linolenic acid is also important industrially it is the major constituent of linseed oil (approximately 47%) which is obtained from flax. The high degree of unsaturation present in this acid makes the oil an excellent drying agent for use in paints, varnishes and inks. 

Apart from paints, electrokinetic separations find limited application for synthetic polymers [905], mainly because of solvent compatibility (CE is mostly an aqueous technique) and competition of SEC (reproducibility). Reasons in favour of the use of CE-like methods for polymer analysis are speed, sample throughput and low solvent consumption. Nevertheless, CE provides some interesting possibilities for polymer separation. Electrokinetic methods have been developed based on differences in ionisation, degree of interaction with solvent constituents, and molecular size and conformation. 

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