INDEX polymer incorporation

The term photochromism can be defined as a light-driven reversible transformation between two isomers possessing different absorption spectra.111,21 The two isomers differ from one another not only in their absorption spectra, but also in their geometrical structures, oxidation/reduction potentials, refractive indices, and dielectric constants. When such photochromic chromophores are incorporated into functional molecules, such as polymers, host molecules, conductive molecular wires, or liquid crystals, the functions can be switched by photoirradiation.[3 61 Photostimulated reversible changes in refractive index can also be applied to optical waveguide switching.171 This chapter reviews applications of photochromic chromophores, especially diar-ylethene derivatives, in various photo switching molecular systems. 

The compound 3-phenyl-anhydro-5-thiolo-l,2,3,4-oxatriazolium oxide 5 (R =Ph) has been incorporated into polymer fdms where its electronic structure and density contribute equally to the measured changes in photoinduced refractive index. Its analogue, 3-phenyl-anhydro-5-hydroxy-l,2,3,4-oxatriazolium oxide 4 (R1=Ph), has been employed as a filter C1999MI6772, 2002MI2290>. 

The refractive index increment dn/dc was measured on solutions of BBB used for light scattering studies. A differential refractometer described previously (5) except for the incorporation of a laser source was utilized. A very large value dn/dc = 0.785 cc./gram was found for BBB. Comparably large values were found for the cis and trans model compounds, each of which had a value of dn/dc different from the polymer. 

Disperse dyes were originally developed for incorporation into certain cellulose acetate fibers. Applications of disperse dyes include the coloring of nylons, polyesters, and acrylics. Since many of these dyes were also designed to be mixed— dispersed —with a dispersant, care must be exercised in avoiding dispersed versions of these dyes, since the dispersants used are not meant to be incorporated in plastics and seriously diminish the brightness and transparency of the dye. Disperse dyes in their pure form are often also classified as solvent dyes, carrying both Colour Index names. Many disperse dyes developed for polyesters are finding use in other polymers. 

Some of the physical properties of the polymer, such as melt temperature and melt index, need to be determined. Design the colorant system to incorporate easily and completely into the base polymer without detracting from its physical properties. 

Analyte adsorption swells the polymer film vertically, which incorporates more of the evanescent field as it swells. The interferometer response is the result of a positive change in the refractive index of the film, and a negative change in phase as the propagating light beam is slowed down by the expanding film. Swelling of a... 

Cotton fibers are single cells composed primarily ( 96%) of the polymer cellulose. In our laboratory (5), cotton fibers were dissolved directly in the solvent DMAC-LiCl. This procedure solubilizes fiber cell wall components directly without prior extraction or derivatization, processes that could lead to degradation of high MW components. MW determinations have been carried out by a size-exclusion chromatography (SEC) system using commercial columns and instrumentation with DMAC-LiCl as the mobile phase. Incorporation of viscometry and refractive index (RI) detectors (6) allowed application of the universal calibration concept (7) to obtain MW distributions (MWDs) based on well-characterized narrow-distribution polystyrene standards (5). The universal calibration concept used by incorporation of dual detectors bypasses the need for cellulose standards. There are no cellulose standards available. Polystyrene standards for a wide range of MWs dissolved readily in DMAC-0.5% LiCl with no activation necessary. 

DMAPMA). H2C=C(CH2)COOCH2N(CH3)3 Properties Pale-yellow liquid. Flash p 140C (CC), refr index 1.4763, d 0.94, bulk density 7.8 lb/gal. Use Reactive cationic monomer, incorporation of amine group into polymers. 

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