Poly refractive index

Di- and poly-halogenated aliphatic hydrocarbons. No general procedure can be given for the preparation of derivatives of these compounds. Reliance must be placed upon their physical properties (b.p., density and refractive index) and upon any chemical reactions which they undergo. 

Poly(vinyl acetate) is too soft and shows excessive cold flow for use in moulded plastics. This is no doubt associated with the fact that the glass transition temperature of 28°C is little above the usual ambient temperatures and in fact in many places at various times the glass temperature may be the lower. It has a density of 1.19 g/cm and a refractive index of 1.47. Commercial polymers are atactic and, since they do not crystallise, transparent (if free from emulsifier). They are successfully used in emulsion paints, as adhesives for textiles, paper and wood, as a sizing material and as a permanent starch . A number of grades are supplied by manufacturers which differ in molecular weight and in the nature of comonomers (e.g. vinyl maleate) which are commonly used (see Section 14.4.4)... 

Molecular weights were measured by gel permeation chromatography on a Perkin-Elmer Series 10 Liquid Chromatograph using tetrahydro-furan as solvent and refractive index as the detection mode. Standards were polystyrene, and reported molecular weights for the poly-siloxanes do not include a correction. 

The high refractive index of Bisphenol A poly(carbonate) (3) is decreased by the incorporation of the Bisphenol AF moiety. The refractive index of Bisphenol A poly(carbonate) (3) is 1.585,9 whereas that of Bisphenol AF poly(carbonate)s (2) is 1.426. Poly(carbonate)s containing a small amount of Bisphenol AF moiety can be used as sheaths of optical fibers of Bisphenol A poly(carbonate) (3). 

The factor f reduces the oscillation amplitude symmetrically about R - R0, facilitating straightforward calculation of polymer refractive index from quantities measured directly from the waveform (3,). When r12 is not small, as in the plasma etching of thin polymer films, the first order power series approximation is inadequate. For example, for a plasma/poly(methyl-methacrylate)/silicon system, r12 = -0.196 and r23 = -0.442. The waveform for a uniformly etching film is no longer purely sinusoidal in time but contains other harmonic components. In addition, amplitude reduction through the f factor does not preserve the vertical median R0 making the film refractive index calculation non-trivial. 

The determination of the molecular weight of nanoparticles is performed by gel permeation chromatography (GPC). The experimental setup consists of a high performance liquid chromatography system with a size exclusion column and a refractive index detector. The nanoparticles are usually freeze-dried and dissolved in tetrahydrofuran for analysis on the system. Poly(styrene) or poly(methylmethacrylate) standards are used to calibrate the column, to enable the determination of number average molecular weight (Mn), as in... 

Clearly, if one is using only a single solvent, these three requisites are mutually exclusive the criteria may well be satisfied with different solvent in each case. Expression (104) means that poly-A and poly-B are iso-refractive and that they have a very different refractive index from that of the solvent. Such systems are comparatively... 

Figure 4.22 High temperature size-exclusion liquid chromatography of an engineering plastic, poly (phenyl sulfate). Column, SSC GPS-3506, 50 cm x 8 mm i.d. eluent, 1-chloronaphthalene flow rate, 1.0 ml min-1 column temperature, 210 °C detector, refractive index detector.

Yang, B., et al., Embedding graphene nanoparticles into poly (N, N -dimethylacrylamine) to prepare transparent nanocomposite films with high refractive index. Journal of Materials Chemistry, 2012. 22(39) p. 21218-21224. 

Poly(vinyl butyral) has clarity and a refractive index similar to glass. It has good flexibility and adhesion to glass, even at low temperatures. It is used as safety glass interlining. 

C poly 1,4-isoprene has a specific gravity of 0.91, a coefficient of linear expansion of 67 X 10 9 cm/cm C, and a refractive Index of 1.5191. This and other elastomers retain their characteristic mobility at temperatures above the Tt. They are brittle at temperatures below Tg. 

Bojkova et al. (4) prepared high-impact poly(urethane-urea) polysulfides having a refractive index of at least 1.57, an Abbe number of at least 32, and a density >1.3g/cm2 3, which consisted of the reaction product of... 

Research Focus Synthesis of poly(thiocarbonate-cothiourethane) derivatives having a high refractive index and Abbe number. 

Poly(urethane urea)polysulfide resins consisting of polycaprolactone diol, 4,4 -methylenebis(cyclohexyl isocyanate), and bis-epithiopropyl sulfide, were prepared by Bojkova et al. (4) and used as optical lenses having good refractive index and good impact resistance/strength. 

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