Pigment characterization

Carotenoids are natural pigments characterized by a tail to tail linkage between two C20 units and an extended conjugated system of double bonds They are the most widely dis tributed of the substances that give color to our world and occur m flowers fruits plants insects and animals It has been estimated that biosynthesis from acetate produces approximately a hundred million tons of carotenoids per year The most familiar carotenoids are lycopene and (3 carotene pigments found m numerous plants and easily isolable from npe tomatoes and carrots respectively... 

Ferric ferrocyanide—Cl Pigment Blue 27, Cl No. 77510. The color additive ferric ferrocyanide is a ferric hexacyanoferrate is a pigment characterized by the stmctural formula Fe4[Fe(CN)g]2ArH20, which may contain small amounts of ferric sodium ferrocyanide and ferric potassium ferrocyanide. ... 

The usefulness of this nondestructive technique may go further than pigment characterization, and it is proposed as an additional method for checking the authenticity of ancient archaeological artifacts. 

BONA pigment lakes are monoazo pigments, characterized primarily by the following general chemical structure ... 

Amorphous silica n. Si02. A naturally occurring or synthetically produced pigment, characterized by the absence of pronounced crystalline structure, and which has no sharp peaks in its X-ray diffraction pattern. It may contain water of hydration or be an anhydrous type. It is used as an extender pigment, fatting agent, and as a desiccant in metal flake and metal powder coatings. 

Phthalocyanine tha-l6- sI-o- nen [ISV phthalic acid + -0- + cyanine] (1933) (cyan) n. Blue and green ink pigments characterized by extreme light fastness and resistance to solvents, acid and alkali. The blue is now widely used in process inks. 

Powder X-ray diffraction is an excellent analytical tool for identification and physical characterization of crystalline samples. It can be used for chemical identification (by matching unknowns with X-ray patterns of known reference samples), for crystal structure information, and for crystallite size determination. Such information is extremely valuable for pigment characterization. Many pigments exhibit polymorphism and each morph can have dramatically different physical properties (shade, opacity, heat stability, surface area, particle size and shape, melting point). These properties define to a large extent the performance characteristics of the pigment and therefore its applications. 

Mearlin Micro Pearls are a series of luster pigments characterized by their very fine particle size. They consist of tin-free, rutile titanium dioxide and/or iron oxide coated mica, implications include plastics incorporation, general coatings and printing inks. 

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