INDEX matrix materials

For some applications, a refractive index is important. A match between the particle size of some barium grades and the refractive index of matrix material allows the formulation of products with desirable optical properties. A series of synthetic barium sulfates is produced by Sachtleben Chemie which have particle sizes between 4 and 10 pm. If the particle size of these barium sulfates is well coordinated with the refractive index of the matrix polymer, semi-opacity combined with translucency results. This permits the foimulation of a light disperser in lampshades or in illuminated advertising displays. The coirect particle size can be calculated from the equation d = (lOOn - 141)/2, where n is the refractive index of the resin and d the particle size of barium sulfate. 

Exxon LL5202.09 LLDPE, a barefoot 12 melt index, 0.924 density polyethylene was used as the carrier resin for preparation of all concentrate formulations. Exxon LL1001.09 LLDPE, a barefoot 1.0 melt index, 0.918 density film resin was selected as the matrix material for the preparation of all letdown compounds. Additive-lree resins were used throughout this trial to minimize potential interactions with additive packages and to simplify the analysis task. 

Because ihe dye molecules are typically randomly oriented in Iheir host matrix, (hey will effectively emit in an isotropic manner. For die inrline spectrum alteration concept, this isotropic emission causes approximately half of the emitted energy to be directed away from the solar cell. However, since the dyes are typically placed in a matrix material widi an index of refraction greater ttoi one and the external medium will either be air or vacuum and dius have an index of refraction near one, some of the energy emitted away from the solar cell will be redirected toward the solar cell by internal reflection. 

A problem with quarter-wavelength layers is to find materials with convenient refractive index, since material with the required refractive index value may not even exist. There are several possible approaches to this problem [158]. One is to utilize a combination of two material furnishing an effective refractive index near the required value. Another way is to deposit two homogeneous layers whose transfer matrix is equal to the matrix of the desired material (the Herpin equivalent-index concept) [159]. Third method is to use AR layers aperiodic both regarding the layer thickness and their composition. It was shown that a combination of an arbitrary number of different materials can be mathematically reduced to a combination of two materials only, for instance by utilizing the equivalent-index concept. This fact may be used to simplify the design of AR layers. 

General-purpose isotactic PP homopolymer (type F401, melting flow index (MI) = 8.5 g/10 min and 6.7 g/10 min, respectively) was provided by Guangzhou Petroleum Chemical Co., China. It should be noted that this is a rather brittle PP, compared to other PP types available on the world market. In addition, a bisphenol-A epoxy resin (type E-51) and 4,4 -diaminodiphenylsulfone (DDS) were provided by Guangzhou Dongfeng Chemical Co., China, as matrix materials. 

When exposed to light, the monomeric material in the photopolymers or photothermoplasts polymerizes, thus locally increasing density and index of refraction. A subsequent fixation process polymerizes the monomer throughout the polymer matrix. 

A simplified performance index for stiffness is readily obtained from the essentials of micromechanics theory (see, for example. Chapter 3). The fundamental engineering constants for a unidirectionally reinforced lamina, ., 2, v.,2, and G.,2, are easily analyzed with simple back-of-the-envelope calculations that reveal which engineering constants are dominated by the fiber properties, which by the matrix properties, and which are not dominated by either fiber or matrix properties. Recall that the fiber-direction modulus, is fiber-dominated. Moreover, both the modulus transverse to the fibers, 2, and the shear modulus, G12. are matrix-dominated. Finally, the Poisson s ratio, v.,2, is neither fiber-dominated nor matrix-dominated. Accordingly, if for design purposes the matrix has been selected but the value of 1 is insufficient, then another more-capable fiber system is necessary. Flowever, if 2 and/or G12 are insufficient, then selection of a different fiber system will do no practical good. The actual problem is the matrix systemi The same arguments apply to variations in the relative percentages of fiber and matrix for a fixed material system. 

Chemical interaction considers the unwanted reactions of process substances with materials in the plant area. These reactions are not expected to take place in the reactor and therefore they are not discussed in the side reaction subindex. The Inherent Safety Index has utilized EPA s matrix (Hatayama et al., 1980) to classify the hazards of the chemical interaction in a process. The worst interaction that appears between the substances present in the plant area is used in the calculations for the Chemical Inherent Safety Index. 

The gratings can also be made in situ by holographic irradiation as was demonstrated for low molecular stilbenes in a polystyrene matrix [197]. Here, the spatial modulation of gain dominates over the refractive index modulation in its contribution to optical feedback. The principles of holographic irradiation will be described in Section VIII, which discusses photosensitive materials. 

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