Effect on color

Ammonium Sulfamate. A number of flame retardants used for ceUulosic materials, including fabrics and paper products, are based on ammonium sulfamate (56). These products are water-soluble and therefore nondurable if treated fabrics are washed or exposed to weathering conditions. For most fabric and paper constmctions, efficient flame retardancy can be provided with no apparent effect on color or appearance and without stiffening or adverse effects on the feel of the fabrics. A wide variety of materials are treated, including ha2ardous work-area clothing, drapes, curtains, decorative materials, blankets, sheets, and specialty industrial papers (57). 

Reactive groups have minimal auxochrome effect on color intensity, and color yield per molecular weight decreases with increasing numbers of reactive groups. Increased dye fixation and reduced environmental impact of hydrolyzed dye more than compensate for color reduction of additional reactive groups. 

Anthocyanins were decolorized at pH 3.0 by the addition of sodinm sulfite at the C-2 or C-4 of the chromophore, a reaction that was rapidly reversible on acidification. Snlfnr dioxide, EDTA, and a combination of snlfnr dioxide and EDTA exerted very small effects on the losses of anthocyanins in strawberry pnrees and juices during 10 wk of storage at -20°C. Conversely, the addition of snlfnr dioxide and storage at 20°C slowed the anthocyanin losses and concnrrently decreased the formation of polymeric componnds, especially in pnrees. EDTA had a slight effect on color stability. ... 

Introduction of an additional substituent such as alkyl, alkoxy, halogen, etc. at 3 -position has a large effect on color. That is, green color changes to red color when there is a tertiary amino group at 2 -position. Thus, 2 -dibenzylamino-6 -diethylamino-3 -methylfluoran (47 R1 = H, R2 = CH3 ),40 2 -dibenzylamino-6 -diethylamino-3 -ethylfluoran (47 R1 = H, R2 = C2H 5),34 3 -chloro-2 -dibenzylamino-6 -diethylaminofluoran (47 R1 = H, R2 = Cl),34 6 -((V-ethyl-4-methylanilino)-3 -methyl-2 -((V-methylanilino)flu-... 

The color of the final product primarily depends on the qualification of the raw materials, TPA, DMT and EG. The content of heavy metals in TPA, residues of catalysts employed during oxidation of p-xylene, and polymer processing affect the final color of the polymer. The tendency of certain catalysts, such as titanium or tin derivatives, to make the polyester yellowish in color is well established. The conversion during esterification is prolonged due to larger TPA particles or their hardness. Color can be influenced by these factors, as well as by chemical impurities in the raw materials, such as water, aldehydes or the quality of insufficiently recovered EG. Similar effects on color can be observed as a result of impurities caused by additives, particularly from less purified Sb2C>3. The quality of the latter can be assessed simply by the color of its solution in EG. 

Figure 18.4 Effect on color of Weather-Ometer testing with ( wet ) and without ( dry ) water spray for Spectar copolymer sheeting [7a]. From Fagerburg, D. R. and Donelson, M. E., Effect of water spray and irradiance level on changes in copolyester sheeting with xenon arc exposure, ANTEC 98 Conference Proceedings, Paper 808, Atlanta, GA, April 30,1998, and reproduced with permission of the Society of Plastics Engineers...

Figure 18.8 Effect on color data of backing with UV-protected sheeting on Spectar UV co-ex sheeting and ABA co-ex sheeting in Miami, FL, exposure [2]. From Weathering of polyester and copolymer sheeting, presentation given by D. R. Fagerburg at the Atlas School for Natural and Accelerated Weathering (ASNAW) course, Miami, FL, May 1999, and reproduced with permission of Atlas Electric Devices Company...

Irradiation (1-2 kGy) of fresh asparagus in combination with wrapping with polyvinyl chloride (PVC) film can double the shelf life under refrigeration with no effect on color and fiavor [44]. 

Table 6.26 Selected Metal Ions and their Effect on Color in Silicate Glasses...

The artworks of Claude Monet reflect the impressionist s focus on light and its effect on color. His objects are independent of form. He gives an impression of a scene. Nothing is painted exactly as it appears. He uses short brush strokes and layers his paints to let light define the hue. 

Substituents on the phenyl groups of 3,3-diphenyl-3//-naphtho[2,l-6]pyran can have substantial effects on color, intensity, and fade. Electron-donating groups in the para position(s) result in a bathochromic shift in the visible spectrum, a lower equilibrium intensity, and a somewhat more rapid fade (Table 3.1). An additional... 

The effect on color reversion by traces of heavy metal ions has been reported (129,155,156,157,158). The presence of ferric and cupric ions... 

To illustrate this effect on colors, three single-pigment colors (blue, red, and yellow) were developed in three different resin systems. Blue and yellow were produced in acetal (POM), polyphenylene sulfide (PPS), and LCP. The red color was prepared in nylon 6,6, PPS, and LCP. The acetal and nylon resins are translucent while the PPS and LCP are opaque at the 3.2-mm sample thickness. In all three colors, the more translucent resins produced visually more brilliant, higher chroma colors than the more opaque resins with increased diffuse scattering. 

The above discussion deals with the base polymer only. One can see that if the additive system imparts light scattering similar to these examples above, the effect on coloring the total resin system can be dramatic. We begin our discussion of additives by looking at polymer blends, where the secondary polymer can be considered an additive to the continuous base polymer. 

Virtually all polymeric resins undergo oxidation in the presence of oxygen. To retard this degradation, antioxidants are typically added. These additives are usually hindered phenols, amines, hydroxylamines, phosphites, or thioesters. In general, antioxidants will have little effect on colorability since they are typically used at low levels. At higher levels, they may increase light scattering and impact colorability depend-... 

In adults maintained on vitamin A-deficient diets for a period of months, there are a number of early signs, apparent before the impairment of dark adaptation impairment of the senses of taste, smell, and balance and distortion of color vision, with impaired sensitivity to green light. With the exception of the effects on color vision, these can all be attributed to dedifferentiation of ciliated epithelia (Sauberlich et al., 1974 Hodges et al., 1978). 

Cooking serves several important functions. It coalesces minute oil droplets into larger ones, which can be easily separated as well as changes the properties of the protein so as to make the oil more easily extractable. But temperature and heating time must be carefully controlled to avoid negative effects on color and sulfur levels in the oil, protein degradation, and the percolation properties of the flaked material. 

Steaks 1% acetic acid or lactic acid Spray No effect on color or odor... 

Loin strips 2% acetic-lactic combination Spray No effect on color... 

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