Ueber die Viscose.
B. M. Margosches (Reprint from Zeitschrift für die gesammte Textil-Industrie, 1900-01, Nos. 14-20).[11]
Report of Committee on the Deterioration of Paper.
(Soc. of Arts, 1898.)
(p. 304) The Report of a Representative Committee appointed by the Society of Arts to inquire into the question of qualities of book papers in relation to their several applications, and more especially for documents of permanent value.
The report first discusses the two directions of depreciation of papers in use: (1) Actual disintegration shown by loss of resistance to fracture by simple strain, and by loss of elasticity—i.e. increase of brittleness; (2) discolouration. These are independent effects, but often concurrent. They are the result of chemical changes of the cellulose basis of the paper, brought about by acids or oxidants used in the process of manufacture, and not completely removed from the pulp, or by acid products of bleaching—e.g. oxycelluloses or chlorinated derivatives; again, by the changes of starch used as a 'sizing' agent, or by oxidations induced by rosin constituents when the rosin is used in excess. Discolouration is an attendant phenomenon of these changes, but is more frequently due to the presence of the lower-grade celluloses (esparto and straw) and the lignocelluloses (mechanical wood-pulp).
The physical and chemical qualities of papers depending primarily upon their fibrous or pulp basis, and in a secondary degree upon the kind and proportion of the constituents added for the purpose of filling and 'sizing,' the report concludes with the following recommendations, positive and negative, under these heads:
The Committee find that the practical evidence as to permanence fully confirms the classification given in the Cantor Lectures on 'Cellulose,' 1897 [J. Soc. Arts, xlv. 690-696], and which ranges the paper-making fibres in four classes:
(A) Cotton, flax, and hemp (rhea).
(B) Wood celluloses, (a) sulphite process and (b) soda and 'sulphate' process.