Impregnation of fibres

Substances used particularly in latex compounding to decrease surface tension, thus increasing wettability and facilitating the impregnation of fibres and fabrics. 

This is a material produced from the impregnation of glass fibre-mat (fibreglass, which is in the form of dry sheet, is commonly known as chopped stranded mat (CSM)) or rovings, with a liquid and unsaturated polyester resin, which thickens chemically to a dry sheet form. The total mix is sandwiched between polyethylene films and then roller-pressed to impregnate and consolidate it. 

There are less exotic ways of increasing the strength of cement and concrete. One is to impregnate it with a polymer, which fills the pores and increases the fracture toughness a little. Another is by fibre reinforcement (Chapter 25). Steel-reinforced concrete is a sort of fibre-reinforced composite the reinforcement carries tensile loads and, if prestressed, keeps the concrete in compression. Cement can be reinforced with fine steel wire, or with glass fibres. But these refinements, though simple, greatly increase the cost and mean that they are only viable in special applications. Plain Portland cement is probably the world s cheapest and most successful material. 

Laminates produced by impregnation of glass and carbon fibre with polyimide resins followed by subsequent pressing have found important uses in the aircraft industry, particularly in connection with supersonic airliners. Such laminates can be used continuously at temperatures up to 250°C and intermittently to 400°C. 

A method of impregnating textile fibres with latex. There is no natural affinity between the textile fibre and the latex particle this is overcome by making the latex slightly acid and the surface of the textile strongly alkaline. 

A textile term denoting a width of cloth as woven in the loom. The meaning has been broadened in the mbber industry to include almost any sheeting such as might be positioned by a web guide, or the mat of fibres later impregnated with latex in the manufacture of non-woven fabrics. See Rubber Webbing. 

SUPreM, Plytron, Quadrax (Gurit Suprem) consolidated tapes or fabrics are made from continuous fibres impregnated with thermoplastic powder. The fibres can be glass, aramid, carbon, steel and the matrices are polyethylene, polypropylene, polyamide, PPS, polyetherimide, PEEK, thermoplastic polyimide, or fluorothermo-plastic. High levels of fibres can be obtained, 65% in volume, for example. 

The "tar" stream which is highly aromatic is made up of tar naphtha, creosote and pitch. The tar naphtha is hydrofined to remove N, S and 0 compounds. It consists mainly of toluenes and xylenes. The creosote can either be sold as such (eg for wood preservation) or be hydrofined to yield a product rich in higher aromatics. The tar pitch is used for impregnating cellulose fibre pipes or is converted to high quality coke (for the production of carbon electrodes). 

The matrices obtained are adherent and comparable to those prepared from B(NHCH3)3.7 However, since (4) can be considered to be a derivative of B(NHPri)3, their interest as BN films precursors may be compared. Thus, after the impregnation of carbon fibres by crude B(NHPr )3, an ammonia treatment was required in order to reduce the volatility of the precursor before pyrolysis. B(NHPr )3, which is stable with respect to autopolymerisation, reacts spontaneously with NH3 leading to a polyborazine with a low carbon content. The BN matrices obtained are not dense and the fibres are not totally embedded, indicating a lack of adherence of the BN matrix onto the fibres. This result could be related to the low hydrocarbon chain ratio of the polyborazine derived from B(NHPr )3, which shorten drastically its carbon wetting properties. 

Rosell A, Palet C, and Valiente M. Solvent impregnated hollow fibre for a selective preconcentration of Pb(II) in an on-hne determination by flame atomic absorption spectrometry. Anal. Chim. Acta 1998 370 141-149. 

Pultrusion is a continuous process involving pulling a collection of fibres on a creel system in the form of a roving, tow, mat or fabric through a resin bath (for impregnation) and then through a heated die to cure the resin and impart a constant cross-section to the product. Figure 6.7. 

Disclosed are dry, disposable, polymeric antimicrobial-applying products having sustained-release antimicrobial activity. They corrsist essentially of a polymeric material, such as a natrual polymer, synthetic polymer or mixture thereof, in the form of fibres, yarrrs, woverr, non-woven and knitted fabrics, sheets and films, and an amine salt antimicrobial agent, which is releasably impregnated into... 

This process has a number of advantages over the more conventional autoclave moulding using pre-impregnated carbon fibre ... 

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