Polymers windows

Multilayer polymer window in currency that diffracts light in a particular pattern... 

XRD requires a periodic two- or three-dimensional structure at the surface of a specimen. The measurements are performed in a similar electrochemical cell as described for XAS. The removal of the electrolyte due to the pressing of the polymer window on the specimen surface reduces the disturbing X-ray scattering from water. The grazing incidence geometry weakens the contribution of the diffraction of the... 

Disposable IR cards with a thin polymer film window are available for the qualitative analysis of liquids. (These cards were originally manufactured by 3M , but are now available from International Crystal Laboratories, Garfield, NJ, and other suppliers.) Two polymer substrates are available polytetrafluoroethylene for the 4000-1300 wavenumber region and polyethylene for the lower wavenumber region. The absorption spectra for these two materials are displayed in Fig. 4.19(b) and (c). A thin film can be deposited onto the polymer window by evaporation from solution or by smearing the liquid onto the polymer. A major advantage of these cards is that the polymer films do not dissolve in water therefore... 

Light element analysis (min. atomic number) 4 4 Both have ability for light element detection providing windowless or polymer window used... 

Entrance window None Varies typically 10 Xm Be. Also ultra-thin polymer windows to extend lower energy range Thin ( 1 mm) Al... 

The windows of the absorption cell are made from polymer material such as polyethylene, poly(ethylene terephthalate Terylene ) or polystyrene. 

In the constmction industry, ceUular polymers are used as spacers and sealant strips in windows, doors, and closures of other types, as weU as for backup strips for other sealants. 

Applications. The applications sought for these polymers include composites, stmctural plastics, electronics/circuit boards, aircraft/spacecraft coatings, seals, dental and medical prosthetics, and laser window adhesives. However, other than the early commercialization by Du Pont of the NR-150 B material, Httie development has occurred. These polymers are quite expensive ( 110 to 2200 per kg for monomers alone). 

The amount of plasticizer added to the polymer in question varies, depending on the magnitude of the effect required. For example, a small addition of plasticizer may be made simply to improve the workabiUty of the polymer melt. This contrasts with larger additions made with the specific intention of completely transforming the properties of the product. For example, PVC without a plasticizer, ie, unplasticized PVC (PVC-U), is used in appHcations such as pipes and window profiles with plasticizer added, articles such as PVC food film, PVC cable insulation, and sheathing and PVC floorings are formed. 

Initially, DADC polymers were used in military aircraft for windows of fuel and deicer-fluid gauges and in glass-fiber laminates for wing reinforcements of B-17 bombers. Usage in impact-resistant, lightweight eyewear lenses has grown rapidly and is now the principal appHcation. Other uses include safety shields, filters for photographic and electronic equipment, transparent enclosures, equipment for office, laboratory, and hospital use, and for detection of nuclear radiation. 

Polystyrene. Polystyrene [9003-53-6] is a thermoplastic prepared by the polymerization of styrene, primarily the suspension or bulk processes. Polystyrene is a linear polymer that is atactic, amorphous, inert to acids and alkahes, but attacked by aromatic solvents and chlorinated hydrocarbons such as dry cleaning fluids. It is clear but yellows and crazes on outdoor exposure when attacked by uv light. It is britde and does not accept plasticizers, though mbber can be compounded with it to raise the impact strength, ie, high impact polystyrene (HIPS). Its principal use in building products is as a foamed plastic (see Eoamed plastics). The foams are used for interior trim, door and window frames, cabinetry, and, in the low density expanded form, for insulation (see Styrene plastics). 

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