Cellulose : an outline of the chemistry of the structural elements of plants with reference to their natural history and industrial uses / Cross & Bevan [C.F. Cross, E.J. Bevan, and C. Beadle].

  • Charles Frederick Cross
Date:
1895
Catalogue details

Licence: Public Domain Mark

Credit: Cellulose : an outline of the chemistry of the structural elements of plants with reference to their natural history and industrial uses / Cross & Bevan [C.F. Cross, E.J. Bevan, and C. Beadle]. Source: Wellcome Collection.

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    OH groups in the cellulose molecule, for in proportion as these are suppressed by combination (with negative radicles to form the cellulose esters) the products exhibit decreasing attractions for atmospheric moisture. It is to be noted that some of these synthetical derivatives are formed with only slight modifications of the external or visible structure of the cellulose, of which, therefore, the phenomenon in question is again shown to be independent. (3) The ‘ condition ’ of the fibre-substance in respect of hygroscopic moisture is an important factor of such properties of fibre as make up its spinning qualities ; it also seriously affects the tensile strength of papers and cellulose textiles. (4) A study of the hydration and dehydration phenomena of the celluloses indicates an unbroken continuity in the series of cellulose-water compounds—or cellulose hydrates ; of which series the £ water of condition ’ or hygroscopic moisture of a cellulose represents the final terms. The proportion of water held by the celluloses in an atmosphere saturated with aqueous vapour is necessarily very much greater than in the ordinary atmosphere, partially saturated at the same temperature. (See H. Muller, Pflanzenfaser, p. 3.) The ‘ moisture of condition ’ is a factor of some moment, first in the buying and selling of fibrous products, and secondly in the processes by which they are worked up (spinning, and ‘ finishing’). (1) In a delivery of 100/. value of a fibrous material, e.g. paper pulp or half stuff, the ordinary variations in the atmospheric moisture may occasion a difference of 1 /. to 2/. in the value. It is important, therefore, to have a normal standard of reference. In the case of wood pulp or cellulose in which there is a large com- merce it is customary to fix this at 10 p.ct., which means that 100 of air-dry pulp give 90 ‘dry’ at ioo° C. If, therefore, in any test the percentage of dry pulp is estimated at any figure, the corresponding percentage of ‘normal’ air-dry pulp (10 p.ct. Aq) is obtained by adding ] to the percentage of dry pulp. (2) Cotton-spinning is carried on under special and carefully regulated conditions of temperature and atmospheric moisture,
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