Glass fibre INDEX

The refractive index is the most important optical property and its effect in determining the appearance of the polymer composite has already been referred to above. Amorphous fillers such as glass fibres and beads have only one refractive index, but most mineral fillers are crystalline and have anisotropic crystal structures resulting in a number of different indices, and this can cause complex and undesirable interference effects [27]. 

Filler Opacify compound, increase hardness, reduce cost Changes refractive index and reflective properties, adds bulk to compound Calcium carbonate, magnesium carbonate, barium sulfate, carbon or glass fibres... 

For small molecules mounted on a glass fibre, the crystal can often be described by indexing the faces of the crystal and estimating their distance from a common point. In such a case a numerical integration can be used. However, this approach is not valid when the crystal is mounted in a capillary surrounded by mother liquor. 

The wave guiding glass fibres consist of a core with refractive index ni and a cylindrical cladding with index 2, so that > n2. A difference of 1% in the indices... 

Table 25. Antifeedant Index ((C-T)/(C+T)( % of Test Compounds [Mean-l-/-(S.E.M.)] in Dnal Choice Test with Glass Fibre Discs [Control (C) Versus Treatment(T)(N=20)I...

A lead glass fibre has a refractive index of 1.682. What is the critical angle for total internal reflection at the interface with an acrylic coating with refractive index 1.498 ... 

Fig. 2.22 Temperature dependence of oxygen index for various plastics 1 rigid PVC, can not be measured above 105 due to softening 2 asbestos-filled phenol/form-aldehyde moulding compound 3 epoxy-modified melamine moulding compound 4 phenol/ formaldehyde moulding compound filled with wood flour 5 glass fibre-filled epoxy resin moulding...

Inert fillers (such as quartz flour, alumina, kaolin, talc, etc.) have a flame-retardant effect in as much as they reduce the flammable proportion in the formulation. Their usually very small influence appears as a slight increase in the oxygen index, while the horizontal and the vertical flame spread rates remain constant even at a high load of these non-inflammable inert fillers. The incorporation of glass fibres may even enhance the flammability when compared to that of the original resin. 

Polyamides are less combustible plastics due to their chemical composition. Unfilled and unmodified PA 6 and PA 66 are rated V-2 according to UL 94, with an oxygen index of about 25 per cent without any added agents. One peculiarity is that glass fibres, mineral fillers, and some additives (such as the impact modifiers) actually enhance the flammability of polyamides they are rated only HB when not flame-retarded. A drawback of polyamides is dripping during the combustion. 

The LOI value increases when the styrene content decreases. This shows the need to limit the amount of styrene in the structure of polyester systems to improve their fire behaviour. With a LOI index of 21-22 these materials with dicyclopentadiene chain ends do not burn in air. Eurthermore, the fact that these materials are not used in the form of the pure matrix, but in the form of composites with glass fibres, would... 

Sepe and co-workers [13] found that automotive components consisting of a metal insert over-moulded with impact modified glass fibre reinforced PET cracked adjacent to the insert following thermal shock testing (100 cycles at -40 to 180 °C). The melt flow index of the material increased by 140% on drying prior to moulding. 

Close to silica fibres are silicate fibres drawn from optical glasses. Silicate fibres are typically applicable in the visible spectral region. Their optical losses in the visible region usually reach much higher values than silica fibres - at least 102dB/km. On the other hand, the refractive index can be tailored in a large interval (from 1.5 for the BK-class to 1.95 for the... 

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