Glass fibre silica

For some non-fire retardant grades of polymers, fire retardancy characteristics might improve when a filler is incorporated into the formulation. Thus, for epoxy resins, the incorporation of minerals, glass fibre, silica or graphite all improve flame spread, flammability and LOI from the poor category for the virgin polymer to the good... 

Industrial grade materials employ fillers such as asbestos, silica and glass fibre. These are incorporated by dry-blending methods similar to those used with woodflour-filled phenolic compositions. 

The extension of an amorphous material under a tensile force can be resolved into three parts first, an immediate elastic extension. Which is immediately recoverable on removing the tensile force Mcondly, a delayed elastic extension which is recoverable slowly and thirdly, a plastic extension, viscous flow, or creep, which cannot be glteovered. With glass at ordinary temperatures, this plastic exten- ion is practically absent. A very slow delayed elastic extension OOCUrs. This effect can be troublesome in work with torsion fibres. The delayed elastic effect in vitreous silica fibres is 100 times less than in other glass fibres, and viscous flow of silica is negligible below OO C (N. J. Tighe, 1956). For exact work vitreous sihea torsion flbres are therefore used. 

Filler/reinforcementi c Active fillerc Carbonates, glass fibres, Al(OH)3, kaolin, talc, silica, wollastonite, glass spheres, mica Al, Ca, Fe, Mg, K, Na, S, Si, Zr... 

In the near-IR, sensors almost exclusively rely on silica fibres (standard or low-OH) as they are accepted as industrially fully applicable32, 33 Silica-based glass fibres are chemically and mechanically robust, easy to handle, inexpensive, available with various core and outer diameters, a core-clad transfer fibres or bare sensing fibres, and have successfully been optimised to their theoretical attenuation limit.34. The spectral window allows application up to 2,5 pm. 

In this procedure the soil sample (spiked with isotopic marker compounds) is processed in a two-part enrichment procedure (Fig. 5.3). In part I, a mixture of the sample and sodium sulphate is subject to solvent extraction, and the extract is, in the same process, passed through a series of silica-based adsorbents and then through the carbon/glass fibre adsorbent. The extract passes through the adsorbents in the following order potassium silicate, silica gel, cesium or potassium silicate, silica gel and finally an activated-carbon... 

Extraction discs (0.5 mm thick, 25 to 90 mm diameter) constitute a variation of column-based SPE. These discs allow rapid extraction of large volumes of sample, which is not possible using a small column. The discs are made of bonded-phase silica particles, a few micrometres in diameter, trapped in a porous Teflon or glass fibre matrix. The discs are operated in a similar way to a paper filter on a vacuum flask. After extraction, the analyte is recovered by percolating a solvent through the filter. The major application of this technique is the isolation of trace amounts of compound dispersed in an aqueous medium. 

Acoustic insulation on the valve body and at least the first five pipe diameters downstream is an effective method of noise treatment to half the loss given in point 1. Note here, however, that the quality of insulation is very important. Although having no particular preference, the author has had reasonably satisfactory results with Refrasil insulation, a high temperature thermal and acoustic insulation made from basalt, glass fibre and silica which reduced... 

In the industrial field, modified silica assists the development of advanced materials. Modified silica powders are used as a filler in rubbers and in new-type gas sensors. Most industrial applications involve the use of strongly related materials such as glass fibres or thin Si02 layers. We wish to restrict ourselves to a discussion of the application of powdered silica and a short indication of related compounds. 

On industrial scale, water or water/ethanol mixtures are mostly used as a solvent for aminosilane modification of silica or glass fibres. Water has a profound effect on the silane structure in solution. Alkoxy groups are hydrolyzed to silanols. Those can combine to form a siloxane linkage between two silane molecules, with production of a new water molecule (reaction (A)). 

Janes, Neumann and Sethna ° reviewed the general subject of solid lubricant composites in polymers and metals. They pointed out that the reduction in mechanical properties with higher concentrations of solid lubricant can be offset by the use of fibre reinforcement. Glass fibre is probably the most commonly used reinforcing fibre, with carbon fibre as a second choice. Metal and ceramic fibres have been used experimentally to reinforce polymers, but have not apparently been used commercially. To some extent powders such as bronze, lead, silica, alumina, titanium oxide or calcium carbonate can be used to improve compressive modulus, hardness and wear rate. 

Fillers. Fillers mentioned for epoxy systems (subsection 2.2.6.4) are used in polyurethanes too. Ground calcium carbonate (coated as well as uncoated) is commonly used. Barium sulphate, silica fumes, wood flour and milled glass fibres are also used. 

Paper Chromatography.—Solvent systems have been developed for the separation of trichloromethyl- phenyl-, and pentafiuorophenyl-phosphonic and -phosphinic acids. Phosphoramidates and their hydrolysis products have been chromatographed, using triethylamine as a buffer. Silica gel on glass-fibre sheets may be used to separate inositol from its phosphate and to analyse phosphatide glyceryl ethers. ... 

In another ALABC project [31], a so-called Silica Powder AGM composed of 70wt.% siliea, lOwt.% polyester fibres (with low melting point and acting as a binder) and 20wt.% glass fibres was subjected to cycling tests to 72% DoD. The initial pressure was 42kPa and the cell achieved about 250 cycles before its capacity fell below 80% of the initial value. 

Practically all types of commercially available thin-layer plates and precoated sheets can be used silica gel, cellulose, kieselguhr, alumina and glass fibres. It is, perhaps, not necessary to emphasize that both one- and two-dimensional arrangements can be materialized as well as different combinations with chromatography and multidimensional procedures [65]. 

Products were separated either on ITLC glass fibre mats (Gelman) or on glass plates produced from a slurry of silica gel G (Brinkmann). After solution was applied to these plates ammonia was added to neutralize the acid and chromatograms were developed with a 50% (V V) petroleum ether (30-60°C.) and benzene solvent. Bands or spots were extracted with ethyl alcohol or water. 

Figure 3.9 Recombinant pDNA purification. Selected transformed clonal bacterial cultures are grown in medium and the pDNA is extracted as shown. Bacterial culture is subject to alkaline lysis. Cellular debris and open-circle DMA is removed and pDNA purified by binding to and eluting from a silica glass fibre filter. Relatively pure pDNA may be obtained following ethanol precipitation and collection of the pellet by centrifugation (illustration of PureLink -HiPure Plasmid Filter Kit http //catalog.invitrogen.com/).

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