Fibres impregnation

Alizarin and the dyes related to it are called mordant dyes " because they are applied to fibres impregnated with metallic hydroxide, i.e. mordanted. 

Towflex (Hexcel Composites) is based on carbon, glass or aramid fibres impregnated with polypropylene, polyamide, PPS, polyetherimide, PEEK. Product forms include flexible Towpreg, woven fabric, braided sleeving, UD tape, chopped compression moulding compound, moulded plates, thermoformable laminates. 

Tepex (Bond-Laminates) is delivered as sheets of 0.25-3 mm thickness based on carbon, glass or aramid fibres impregnated with polyamide or thermoplastic polyester. Fibre levels range from 35% up to 85%. 

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. 

Prepare platinized asbestos as follows put 5 g of purified asbestos into a bowl and pour a 1-2% cbloroplatinic acid solution over it. Transfer the fibres impregnated with the solution into a porcelain crucible and roast them first carefully, and then strongly on a blowtorch. Store the prepared catalyst in a jar with a ground-glass stopper. Roast the platinized asbestos -without fall before each experiment. 

At the present work the process of carbon structuring is studied at carbonization in temperature of heat treatment (THT) 400-900 °C of hydrated cellulose (HC) fibres, impregnated by the salts of metals of ferrous subgroup, that was resulting to formation of metal-carbon fibres (Me-CF). 

Bone is the hard material that forms the skeleton of most vertebrate animals. It consists of a network of collagen fibres impregnated with mineral salts, mostly calcium phosphate. Bone varies in strength and can be as tough as reinforced concrete. Most bones are hollow, the cavity being filled with soft, spongy material. The solid part is interspersed by Haversian canals, which are tiny canals carrying blood, nerves and lymphatics. 

In this equation S is the coefficient of scatter of the solid phase and e the coefficient of absorption of the liquid component. The equation approximates the behaviour of the diffuse reflector in cases where the difference of intensity between the incident and the reflected rays is independent of the thickness of the structure. This is the case with the fibre-impregnated system, and hence the equation is an approximate description of its behaviour. 

I he normal method of application for cellulosic fibres must be modified because the alkalinity of the solution of the azoic coupling component would saponify the fibre. It is also not practical to couple a fibre impregnated with a naphthol with the diazotized base because, in the conditions under which the operation is carried out, the fibre is unswollen and the molecules of the diazonium compound cannot enter. 

Details are given of a two-stage method for obtaining polyacrylonitrile fibres with antibacterial properties. The method consists of the incorporation of carboxylic groups into the fibres followed by fibre impregnation with gentamycin, neomycin, or penicillin solutions. Characterisation was undertaken using FTIR and proton NMR. 29 refs. 

Fibres impregnated with weakly nitrated nitrocellulose, n.o.s. (including toe puffs, nitrocellulose base), see Nitrocellulose Products, p.l61... 

Squibs are cotton yams or other fibres impregnated with black powder and which bum with an external flame to ignite pyrotechnics, although the term may apply to small pyrotechnic or explosive devices. Safety squibs are those squibs which do not bum with an external flame. Electric squibs are essentially synonymous with the matchheads (bridgewire-low explosive combinations) used in electric detonators as well as a type of jet thmst igniter. 

Figure 5. Photomicrograph (lOx) of prepreg cross-section showing fibre impregnation.

Woven glass fibre, impregnated with polysilicic acid, which has a separating potential similar to that of thin layers of silica gel, has been used as a chromatographic support and sorbent because solvents migrate approximately twice as fast as on t.l.c. plates. The use of this fibre has allowed the separation of D-[ Cl-glucose and D-[ C]fructose in a time comparable to the half-life of [ C] (20.4 min). 

A widely used method of laminate construction is by the contact moulding process or hand lay-up . In this, a layer of catalysed unreinforced resin, known as the gelcoat , is brushed or sprayed onto the mould and allowed to cure and then layers of reinforcing-fibre impregnated with resin are built up behind (Fig. 6.3). Variations of this include resin injection and vacuum-assisted resin injection in closed moulds. After removal of the cured moulding from the mould, the gelcoat forms the outer skin and as such performs the two functions of decoration and protection ... 

Clariant offers a maleated PP imder the Hostamont name. Around the end of 2003 Clariant also introduced a maleated polypropylene wax called Licomont AR 504 as a coupling agent and compatibihser, also for wood and natural fibre composites. The viscosity was deliberately low to facilitate fibre impregnation. Benefits claimed were improvements in the toughness and elasticity of the products. 

Unsaturated polyester (uPES) resins based on phthalic anhydride were obtained in the 1930s and were known as alkyd or glyptal resins. Crosslinked with polystyrene (PS) they were, and are still used, for fibre impregnation to produce plastic composites. uPES is among the four most important thermosetting resins besides PF, UF and epoxy (EP) resins and nowadays they represent about 20% of the total volume of thermosets [6]. 

Dub6 et al. (1995) addressed both the issues of volatiles and fibre wetting with reaction injection pultrusion (RIP) process used to produce thermoplastic polyurethane and thennoset polyisocyanurate matrix composites. The low viscosity constituents used in RIP help in improving fibre impregnation, while the small volume of the impregnation bath reduces emissions. 

The load is transferred from matrix to wires not only by bonding but also by nodes and transverse wires. That is the reason the crack pattern visible on ferrocement elements often reflects the distribution of wires and nodes. The nodes in nets are the origin of stress concentrations and the regular distribution of wires often corresponds to the crack pattern that appears in service. There are several techniques to improve ferrocement properties by addition of thin fibres, impregnation, etc. 

An interesting new product from Japan s Kyocera Chemical Corporation is a flexible fibre-reinforced plastic circuit board which is manufactured from a non-woven cloth of glass fibres impregnated with epoxy resin and sandwiched between layers of copper foil. 

YSZ Hollow fibre impregnated Ni catalyst Coke is regenerated by permeated oxygen 121... 

Even DuPont, however, encountered the odd banana skin on their triumphal path. Corfam, their artificial leather, proved a 70 million fiasco. It was nearly a decade in the making, and was meant for shoes that would not only breathe but would resist wear and retain a high polish for ever. The material comprised a web of polyester fibres, impregnated with polyurethane and covered with a polyurethane coating. The soles were porous (a million pores per square centimetre, the advertising proclaimed). But the material was not compliant, feet felt hot, and the appearance of the product did not please buyers when it came on the market in 1963. DuPont eventually sold the patent for a derisory sum to an organization in Poland, and thence into oblivion. 

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