Color and Optical Properties

Synthetic polymer fibers typically are white or ofiF-white when they are manufactured. Some special synthetic polymer fibers have other types of color. For example, as-spun Kevlarfibers typically are yellow. In addition, synthetic polymer fibers with different colors also can be produced by adding pigments dining fiber formation or by dyeing after the fibers are formed. Natural cellulose and protein fibers exhibit great color difference by nature, and their color also can be modified by dyeing. 

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More information on color and optical properties in general is in ... 

Part III of the book discusses different properties of fibers. Fiber properties ean be classified into primaiy and secondary properties. Primary properties are those that fibers must possess so they can be converted into useful products. Examples of primary properties are aspect ratio, strength, flexibility, cohesiveness, and uniformity. Secondary properties are those that are desirable and can improve consumer satisfaction with the end-products made from the fibers. Secondary properties include, but are not hmited to physical shape, density, modulus, elongation, elastic recovery, resilience, thermal properties, electrical properties, color and optical properties, moisture regain, resistance to chemical and environmental conditions, resistance to biological organisms, and resistance to insects. Chapter 14 provides an introduction to these primary and secondary properties. 

Figure 11.2. Nanowire electronic and optical properties, (a) Schematic of an NW-FET used to characterize electrical transport properties of individual NWs. (inset) SEM image of an NW-FET two metal electrodes, which correspond to source and drain, are visible at the left and right sides of the image, (b) Current versus voltage for an n-type InP NW-FET. The numbers inside the plot indicate the corresponding gate voltages (Vg). The inset shows current versus Vg for Fsd of 0.1 V. (c) Real-color photoluminescence image of various NWs shows different color emissions, (d) Spectra of individual NW photoluminescence. All NW materials show a clean band-edge emission spectrum with narrow FWHM around 20nm. (See color insert.)...

The visual appearance and optical properties of a material depend on its color and additives, etc., as well as on the nature of its surface. Gloss is a term employed to describe the surface character of a material which is responsible for luster or shine, i.e., surface reflection of a polymeric material. 

Zanardi-Lamardo, E., Clark, C. D., Moore, C. A., and Zika, R. G. (2002). Comparison of the molecular mass and optical properties of colored dissolved organic material in two rivers and coastal waters by flow field-flow fractionation. Environ. Sci. Technol. 36(13), 2806-2814. 

Werner and his co-workers (Tables I and II) proceeded in a very systematic fashion, and a series of cobalt compounds was not only made but was also identified, and properties were noted or measured (color, chemical reaction, electrical conductivity, and optical properties). Some of his students and co-workers continued to investigate cobalt compounds after having accepted positions in other universities or returned to their native countries. 

Other papers incorporating optical data on micas included Seal et al. (1981), who characterized giant radiohaloes in biotite Finch et al. (1982), who coupled Mossbauer data with their earlier work correlating color with optical properties and Bakhtin et al. 

It is not clear why the earlier workers observed only the yellow or brown color and not the blue color. This may be due to differences between the anhydrous and hydrated materials and/or to differences in the production or stability of the 670 nm band. Since this band was found to be unstable at room temperature [59], it is possible that it was sufficiently unstable in their samples so as to be unobservable. It is also evident that under some irradiation conditions the band is not produced, so that the band may be due to an impurity which is not present in all samples. It is necessary to determine the defect responsible for this band before it is possible to resolve this matter. There is evidence that a band at 565 nm in KN3 is associated with the N2 defect [69], and it is tempting to associate the 670 nm band in Ba(N3)2 with this defect. The observations that after X-irradiation at room temperature or at 78°K the NJ defect is not observed and that the samples are yellow-brown, thus indicating the absence of the 670 nm band, tend to support the speculation. The NJ defect was also observed in Ba(N3)2 H20, but there is no information regarding color or optical properties [37]. There is, in addition, reason to associate the 300-nm band in Ba(N3)2 with the NJ molecular ion. Marinkas found an excitation band for conversion of NJ to N3 in this same region [52]. Correlated studies by magnetic resonance and optical absorption of Ba(N3)2 should further identify and characterize the irradiation-induced disorder. Studies by these techniques and of gas evolution will then undoubtedly enable the mechanism of decomposition to be established. 

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