Selected pigments

Theie aie several additional factors that must be considered in selecting pigments for a specific coating application (40). These factors include processing stabihty requirements, pigment uniformity and reproducibiUty, particle size distribution, dispersibiUty, and compatibiUty of all materials to be used. 

K.J. McGraw, M.D. Beebee, G.E. Hill and R.S. Parker, Lutein-based plumage coloration in songbirds is a consequence of selective pigment incorporation into feathers. Comp. Biochem. Physiol. Part B 135 (2003) 689-696. 

Figure 2.39 Triboelectric series and selected pigments used in commercial toners.

Borax or borax-boric acid coatings containing a carbohydrate binder, with selected pigments. The borax or borax-boric acid combination will liberate the usual moisture when heated, with the binder and pigment furnishing some insulation. This type of coating has fair flame resistance. 

Intumescent types of aqueous coatings have been produced containing an amine aldehyde, the ammonium salt or salts of polyhydric acid, selected pigment, starch, and thickener. When formulated properly, this type of coating possesses excellent fire- and flame-resistant properties, but would be rated as a relatively poor paint film. 

Table II. Visual Detection Limits for Selected Pigments...

We have also obtained solid state C NMR spectra of a few selected pigmented coatings and these results are similar to those found for the unplgmented system. At this time the KMR results are of use only to corroborate the Infrared results. 

Table 10.1 Comparison of Selected Pigments Dried in a Spray Dryer with Shock-Wave Atomizer with a Reference Pigment... 

Organic pigments are shown in Table 4.2. For selected pigments, the chemical names are shown in Table 4.3... 

Sherma et al. (1992) separated chloroplast pigments on silica gel and seven types of bonded silica gel plates. Spinach leaves were extracted in acetone, and the best overall separation was done on a Cig (Whatman) reversed-phase plate using the solvent system petroleum ether-acetonltrile-methanol (2 4 4). The Rf values and wavelengths (in nm) of maximum absorption of selected pigments on the Cjg layers were as follows P-carotene, 0.08, 455 nm pheophytin, 0.24, not available chlorophyll a, 0.36, 420 nm and neoxanthin, 0.75, 440 nm. 

In most commercial applications, where rapid degradation is not required, it is convenient to prepare a concentrate containing 2 to 5% of the ketone monomer. This concentrate, which may also be coloured with selected pigments, can then be blended with natural resin in ratios of 1 9 to 1 20 and extruded or moulded to provide products with the desired rate of degradation. Control of the rate is provided by changes in concentrate and/or pigment... 

Another type of sample requiring specific treatment is that with a high-lipid content. The presence of such compounds interferes in the whole process of isolation and subsequent purification. They can be removed by means of selective phase distribution, using two solvents one with high affinity for fat and the other with selective pigment-retention capacity. 

Select pigments with a least tendency for chalking. 

A monofunctional amine synergist which, when used in conjunction with a photosensitizer such as benzophenone, promotes rapid curing luider UV light. Additional benefits include reduced odors both at press side and in the cured film, reduced blooming or migration, and color fading of selective pigments such as reflex blue and rbodamine red. 

Figure 11 Elaborately historiated initial R in sixteenth-cerrtury German choir book, with Raman microscopy spectra of selected pigmented regions. Reproduced with permission of Clark RJH (1995) Raman microscopy application to the identification of pigments on medieval manusorlpts. Chemical Society Reviews 187-196 The Royal Society of Chemistry. (See Colour Plate 5a).

Plate 5a Elaborately historiated initial R in sixteenth-century German choir book, with Raman microscopy spectra of selected pigmented regions. See Art Works Studied using IR and Raman Spectroscopy. 

Figure 6. Transmission spectra of two 30% glass fiber reinforced PA6 compounds. One contains carbon black and absorbs light over the whole spectrum. The second contains selected pigments which render it transparent for IR radiation, while it still appears black in the visible spectrum. Thickness is 3 mm. 

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