Special Colorant Classes

Several types of dyes or colorants do not fit logically into the other classifications and have been included in this special classification. Disperse dyes are small polar dye molecules which can be used to dye thermoplastic fibers such as triacetate, nylon, polyester, and other synthetic fibers. Solvent dyes are dyes which are specially formulated so that they can be applied from solvents other than water. Pigments are not dyes at all, but rather colorants that must be incorporated in the fiber during spinning or fixed on the surface of the fiber by use of a polymer adhesive. Natural dyes are complex mixtures derived from natural sources which can be placed in a number of the above classifications. 

Disperse Dves Disperse dyes were formulated and introduced to permit dyeing of hydrophobic thermoplastic fibers including acetate, triacetate, nylon, polyester, acrylic, and other synthetics. The disperse dyes are 

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Special Colorant Classes Disperse dyes Solvent dyes Pigments Natural dyes... 

This is an interesting class of pigments that are capable of producing special color or visual effects when used in coatings. Special effect pig-... 

Verdrazyls, e.g., 210, are a class of cyclic free radicals, with characteristic ESR spectra and intense colors. They represent a special case of oxidation of formazans and can be obtained from the methylation of and simultaneous or subsequent dehydrogenation of formazans.359-361 Ver-... 

The book is divided into seven chapters. Chapter 1 describes photo-chromic materials which have critical applications in memory technology. These compounds generally are activated by light. Chapter 2 covers leuco quinones which, in many cases, when oxidized, have their absorption maxima in the near-infrared region. Chapter 3 describes leuco dyes of a common group of compounds—oxazine, thiazine, and phenazines—that have found applications in color photography. Chapters 4-6 describe arylmethine-type compounds that can be triggered to dyes by common chemistry. Chapter 7 describes a special class of leuco dyes, namely, tetra-... 

Traveling around the state installing his machinery, Rillieux had to stay on slave-operated plantations. Like many free people of color, Rillieux may have regarded himself as the equal of the white ruling class, far above dark-skinned slaves. But in the antebellum South, Rillieux could not stay in the plantations mansions. Rumor had it that he stayed in slave quarters, but a firsthand observer reported that on Benjamin s plantation Rillieux was given a special house and slaves to serve him. 

P.R.8 is used in a variety of special media outside the paints, printing inks, and plastics field, which is also true for other members of this class of pigments. One such application is in the paper industry, where the pigment is used for mass coloration and surface coating formulations. It also lends itself to application in artists colors and office articles. 

Benzenoid (chemical) isomers are, in a strict sense, the benzenoid systems compatible with a formula C H, = (n s). The cardinality of C HS, viz. C HS = n, s is the number of isomers pertaining to the particular formula. The generation of benzenoid isomers (aufbau) is treated and some fundamental principles are formulated in this connection. Several propositions are proved for special classes of benzenoids defined in relation to the place of their formulas in the Dias periodic table (for benzenoid hydrocarbons). Constant-isomer series for benzenoids are treated in particular. They are represented by certain C HS formulas for which n s = In Sjl = n2 52 =. .., where (nk sk) pertains to the k times circumscribed C HS isomers. General formulations for the constant-isomer series are reported in two schemes referred to as the Harary-Harborth picture and the Balaban picture. It is demonstrated how the cardinality n s for a constant-isomer series can be split into two parts, and explicit mathematical formulas are given for one of these parts. Computational results are reported for many benzenoid isomers, especially for the constant-isomer series, both collected from literature and original supplements. Most of the new results account for the classifications according to the symmetry groups of the benzenoids and their A values (color excess). 

In contrast to organic chromophores, luminescent lanthanide complexes are believed to be promising candidates to solve this problem. The spectroscopic properties of some lanthanide ions are ideal for use in full color displays, as is known from inorganic luminescent materials in cathode-ray and projection television tubes. Luminescent lanthanide complexes belong to a special class of emitters, exhibiting the following important advantages. 

Interpretation of the membrane proteins in an envelope virus can be assisted by the identification of transmembrane a helices. Membrane proteins represent a special class of proteins because of the predominant presence of transmembrane helices connected by extramembrane loops and domains. For example, even at 10.5-A resolution, a pair of transmembrane helices could be identified in the Semliki Forest virus El and E2 proteins (Eig. 10 see Color Insert). 

Since World War I, the dye industries, backed by adequate resources and research facilities have flourished. As a result of this development we were able to dye with fast colors during World War II the largest output of highgrade textiles of all the warring countries. Furthermore, with the cessation of hostilities we remain entirely independent of foreign sources in all classes of dyestuffs and even lead the world in total production in this highly technical and specialized field. 

The attraction that the polynuclear transition metal cyanides have always had for chemists may be ascribed mainly to the characteristic deep colors of some members of this class of compotmds. These inorganic poisoners offer a rich variation in their stoichiometries and hence in their electronic properties. The broad range of different compounds having the general composition Mt[M (CN) i]j H20 is due to the large number of possible combinations of transition metal ions and M , particularly by considering the different possible oxidation states. As special cases we will find a number of mixed valence compounds, a class of compounds which has attracted widespread attention during the last few years (77, 18). 

Besides disinfection and stain removal, there are few other added benefits of major market importance. The next most important is the special class in which a polymer film is left behind on the surface. The most common example of this is not all-purpose cleaners, but are the mop and shine products for floor cleaning. This subset is intended solely for floor cleaning and leave behind a film intended to mimic the shine and soil resistance of waxing a floor. Unlike waxes, however, these polymer films do not need to be buffed to make them glossy [176], The only drawback to this kind of formula is the possible buildup of polymer on the surface. These polymer films tend to be slightly colored, and so repeated layers can yellow the surface. The aim of inventions in the field is therefore... 

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