Paper, fibre

The main features of PC are low cost, need for small sample amount, high level of resolution, ease of detection and quantitation, simplicity of apparatus and use, difficult reproducibility (because of variation in fibres) and susceptibility to chemical attack. Identification of the separated components is facilitated by the reproducible Rj values. Detection methods in PC have been reviewed [368]. Fluorescence has been used for many years as a means of locating the components of a mixture separated by PC or TLC. However, also ATR-IR and SERS are useful. Preparative PC is unsuitable for trace analysis because filter paper inevitably contains contaminants (e.g. phthalate esters, plasticisers) [369]. For that purpose an acceptable substitute is glass-fibre paper [28]. 

The nomenclature given for these componnds is a nniversally recognised system for the naming of dyestuffs devised by the Society of Dyers and Colourists as part of their Colour Index (Cl). The Cl Generic Name is made up of the application class, the hne and a nnmber. Acid dyes are nsed on wool and polyamide, direct dyes on cel-lulosic fibres, paper and leather, disperse dyes on polyester fibres, reactive dyes on cellnlosic fibres and basic dyes on polyacrylonitrile and paper. 

For example, strongly alkaline or strongly acidic reaction mixtures weaken cellulose filter papers. Acid-hardened grades which are more chemically resistant are commercially available (e.g. Whatman filter papers) but for maximum resistance to chemical attack, glass-fibre paper (e.g. Whatman) or a glass funnel fitted with a fixed sintered glass plate (Section 2.11) may be used. 

Iterated from the right end of the electric circuit (far away from the carbon-fibre paper), the impedance at segments k is related to the circuit impedance from segments (k+1) to the one furthest to the right, by the following equation ... 

The activities of CNTs have been evaluated by Girishkumar et al. [7] using ex situ EIS. Their study was conducted in a three-compartment electrochemical cell using a GDE electrode (a carbon fibre paper coated with SWCNTs and Pt black as an anode or cathode). Electrophoretic deposition was used to deposit both the commercially available carbon black (CB) for comparison and the SWCNT onto the carbon Toray paper. Commercially available Pt black from Johnson Matthey was used as the catalyst. In both cases, the loading of the electrocatalyst (Pt), the carbon support, and the geometric area of the electrode were kept the same. EIS was conducted in a potentiostatic mode at either an open circuit potential or controlled potentials. 

A chromatographic bed the stationary phase may be packed into a glass or metal column, spread as a thin layer on a sheet of glass or plastic, or adsorbed on cellulose fibres (paper). 

Chromatography.2 Reverse phase chromatography on glass fibre paper using silver fluoroborate solutions as eluants has proved useful for separation of sesquiterpenes, even of mixtures that appear homogeneous on alumina and by gas-liquid chromatography. Silver nitrate is too insoluble to be used. 

The filter can consist of up to three elements. The outer element is a particulate filter, often made of glass fibre paper, pleated to increase surface area. The inner element is a vapour adsorbent, usually activated granular charcoal. The third element comprises various chemicals impregnated on to the charcoal, such as copper, chromium, silver and triethylenediamine (TEDA), to react with volatile chemical agents such as hydrogen cyanide and cyanogen chloride that are poorly adsorbed. 

Fig. 6.8. Cross-sectional view of apparatus for electrophoresis in fused salts, (a) Electrophoresis chamber (b) Pyrex glass plate (c) Pyrex vessels (d) glass fibre paper (e) capillary with a screw to move it in all directions (0. furnace with heating and temperature regulating system g.i., gas inlet tube g.o., gas outlet tube.

Fig. 5 Miciostructures of alumina filler loaded preceramic paper left - pulp fiber paper sintered al 1600 °C (porous) right - fracture surface of sintered alumina fibre paper.

Explosive articles include a wide variety of devices or tools that employ explosives which on initiation produce a sudden, powerful expansion of gases used to some mechanical advantage drive turbines, move pistons, shear bolts and wires, operate pumps, and start engines. Often, these articles contain an explosive cartridge, an explosive charge encased in a cartridge case made of metal, fibre, paper, plastic, or other material. 

Reaction with titanium (I V)-activated derivatives of polypropylene netting, zirconia fibre sheet, and glass fibre paper Reaction with azide derivatives of controlled pore glass and silica Unspecified method of covalent binding to Amberlite XAD-7... 

Nomex Du Pont 220 — v-0 Reinforcing fibre, paper-like film... 

For many years, cells with electrolyte gelled by the addition of sodium siUcate or sulphuric acid adsorbed onto a felted glass fibre mat or thick paper have been manufactured such cells avoid the hazards of acid spillage and were sold mainly for aircraft or motorbikes. Now cylindrical lead/acid cells, typical capacity 2 A h and without free electrolyte, are produced to compete with small Ni/Cd and primary cells for the consumer market. These cells are spirally wound (as a Swiss roll) with electrodes of thin, pure lead sheet perforated to increase the amount of pasted active material adhering to the metal and an adsorbent glass fibre paper separator, packed into a metal can. 

Round glass-fibre-paper filters, 27 mm diameter, fibre diameter 0.5 to 1.3 pm... 

Watt W, Johnson W, Carbon fibres from 3 denier polyacrylonitrile textile fibres, Paper presented to 3 Conference on Industrial Carbons and Graphite, London, 1970. 

Reynolds WN, Structure and mechanical properties of carbon fibres, Paper 7.2, Conf Industrial... 

Furukawa S, Otani S, Kojima A, Miyamoto M, Preparation of eement mortars reinforced with a small amount of carbon fibre paper, TANSO, 129, 59, 1987. 

Zhang WM, Chtai J, Wagner P, Swiegers GF, Wallace GG (2008) Polypyrrole/Co-tetraphenylporphyiin modified carbon fibre paper as a fuel cell electrocatalyst of oxygen reduction. Electrochem Commun 10(4) 519-522... 

Oxygen reduction studies and cyclic voltammetry were carried out at ambient temperature (22 2°C) in 1 cm gas diffusion electrodes as previously described (8). The catalyst, mixed with ca. 50 mass % PTFE as a binder (and Nafion solution in one case), was spread on carbon fibre paper (CFP Toray TGPH090), which was then hot-bond to a Nafion 117 membrane. In the cell, a controlled flow of gas (O2, or N2 for cyclic voltammetry) was passed over the CFP and the membrane was in contact with a 1 M H2S04(aq) solution containing counter and reference (SCE) electrodes. 

Papermaking technology is used to make filter papers and sheets from cel-lulosic materials and glass fibres. Papers made from synthetic polymer, ceramic or metal fibres that are bonded and sintered are also available. 

Acid dyes are employed above all for colouring wool, polyamide fibres, paper, leather and inks. Only certain acid dyes are permitted for colouring foodstuffs and such food colorants are therefore treated in a special section below (p. 623). The difficultly soluble salts of some acid dyes are used as pigments. Most acid dyes are azo-, triarylmethane-, xanthene-, or anthraquinone derivatives. Various investigators have reported PC-separations of acid dyes in detail [12, 31, 33, 40]. Such separations can be carried out more quickly with TLC and often with superior resolution. Table 131 summarises experimental conditions of the abundant work in this field. 

Direct dyes are used for colouring cellulose fibres, paper and leather. They are principally polyazo dyes of comparatively high molecular weight. Various authors have reported the separation of direct dyes... 

---