Cellulose fibre

HN —R —NH —R ),. Hydrophilic polar substances formed by reacting alkylene polyamines or simple amines with alkylene dihalides. Used as flocculants, for, e.g. cellulose fibre and mineral ore suspensions. 

B. V. Hettich, "Regenerated Cellulose Fibres—Technology foi the Future," 30th Annual TPIMeeting 1980. 

P. H. Hermans, Physics and Chemistry of Cellulose Fibres, Elsevier, Amsterdam, Nediedands, 1949, p. 197. 

C. Preston, ed.. The Dyeing of Cellulosics Fibres, Dyers Company PubHcations Tmst, London, 1986. 

Fig. 26.3. The molecular structure of a cell wall. It is a fibre-reinforced composite (cellulose fibres in o matrix of hemicellulose and lignin).

Wood, then, is a foamed fibrous composite. Both the foam cells and the cellulose fibres in the cell wall are aligned predominantly along the grain of the wood (i.e. parallel to the axis of the trunk). Not surprisingly, wood is mechanically very anisotropic the properties along the grain are quite different from those across it. But if all woods are made of the same stuff, why do the properties range so widely from one sort of wood to another The differences between woods are primarily due to the differences in their relative densities (see Table 26.1). This we now examine more closely. 

This material has been known for many years, being used originally in the making of electric lamp filaments. In principle vulcanised fibre is produced by the action of zinc chloride on absorbent paper. The zinc chloride causes the cellulosic fibres to swell and be covered with a gelatinous layer. Separate layers of paper may be plied together and the zinc chloride subsequently removed to leave a regenerated cellulose laminate. 

Cellulose may be solubilised by treatment with sodium hydroxide and carbon disulfide. It can be regenerated by acidification of the solution. This is the basis of the production of regenerated cellulose fibre, so-called viscose rayon , which is a major textile fibre. The technique is also used for the production of continuous cellulose-derived film, so-called cellophane (from cellulose and diaphane , the latter being French for transparent). 

During this period a number of attempts at reinforcing these cements were made. Fillers described include carborundum (Salzmann, 1930), cellulose fibres (Schonbeck Czapp, 1936) and even diamonds (Salzmann, 1930). None of these innovations found their way into commercial materials (Palfenbarger, Schoonover Souder, 1938). 

P. D. Gullett and P. F. Head. Materials incorporating cellulose fibres, methods for their production and products incorporating such materials. Patent WO 9318111, 1993. 

Scheme 1.1 The reaction of Procion dyes with cellulosic fibres...

The traditional use of dyes is in the coloration of textiles, a topic covered in considerable depth in Chapters 7 and 8. Dyes are almost invariably applied to the textile materials from an aqueous medium, so that they are generally required to dissolve in water. Frequently, as is the case for example with acid dyes, direct dyes, cationic dyes and reactive dyes, they dissolve completely and very readily in water. This is not true, however, of every application class of textile dye. Disperse dyes for polyester fibres, for example, are only sparingly soluble in water and are applied as a fine aqueous dispersion. Vat dyes, an important application class of dyes for cellulosic fibres, are completely insoluble materials but they are converted by a chemical reduction process into a water-soluble form that may then be applied to the fibre. There is also a wide range of non-textile applications of dyes, many of which have emerged in recent years as a result of developments in the electronic and reprographic... 

Azoic dyeing of cellulosic fibres is a process that is used only to a small extent today. In this process, an azo pigment is formed by chemical reaction within the fibre. The cotton fibres are first impregnated with an appropriate coupling component such as the anilide of 3-hydroxy-2-naphthoic acid, 156, under aqueous alkaline conditions. The fibre is then treated with a solution of a stabilised diazonium salt, in which the... 

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