From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Description of various cellulose-based materials like celluloid and acetylene-cellulose, their properties, and production methods for use as insulators.
| Identifier | ExFiles\Box 24\2\ Scan099 | |
| Date | 25th January 1921 guessed | |
| - 12 - with nitro-glycerine forms smokeless powder. Soluable nitro-cellulose, a mixture of tetra-nitrate C 12 H 15 (O.N.O.2) 5 O5 together with hot nitric acid produced celluloid by the admixture of camphor. Camphor originates from the camphor tree that is indigenous to Formosa. It can also be made synthetically from Turpentine oil. Celluloid is an insulator and is used for special purposes, for instance, for the manufacture of accumulator boxes and in the construction of instruments, but its extensive use is hindered by the fact that it is easily softened and its use attended with great danger of fire as it is even found liable to explode by impact, and these undesirable qualities cannot be removed even by the addition of insert materials. Recently a number of other materials have become important as electric insulators. These materials are also produced from cellulose and have great advantage of not being inflammable. These are cellons which are produced from Acetylene-celluloses. These are produced by warming cellulose in a sealed glass tube with acetic acid. If hydro-cellulose is used instead of cellulose the combination is easier and takes place already at 120 degrees. It is also possible to obtain acetylene-cellulose at much lower temperatures if a catalytic agent is used, that is to say a material that initiates the reaction and hastens it. Acetic acid or methylic alcohol is obtained from the dry distillation of wood. Catalysis may be induced by sulphuric acid which also favors the change of cellulose into hydro-cellulose. In consequence of the low temperature of 40 to 70 degrees that is required only a small destruction of the cellulose molecule is produced. Acetic acid may be used to thin the material that is produced. After the acetylene-cellulose has been dissolved in a mixing drum, it is separated from its acetic acid solution by water, benzol, ether or carbonic sulphide and separated from the materials that adhere to it by washing it vigorously with water, or any traces that remain cause further decomposition. The drying should take place at a temperature not exceeding 100 degrees. A number of other catalytics may be used, such as organic and inorganic compounds, halagene compounds and many others. Acetic acids enter into a varied number of compounds with cellulose in the proportion of 14.7% in (C H3. C.O.O.) 2 (O.H.) 18. C 24. H 20 up to the highest value of 62.5% in (C H 3 C.O.O.) 12 (O.H) 8 C 24 H 20. The properties and solubilities of the materials produced differ according to this percentage content. These are acetic celluloses that are insoluble in acetone (C H3. C.O.O. H3) Chloroform (C H C13) and other solvents, and others that are soluble in these with the greatest ease. There are a number of methods of transforming the acetylene-cellulose into horn-like substances. Amongst these may be mentioned the method of Dr.Eichengrun of manufacturing cellons which has been very successful in practice. He starts with acetylene-cellulose that is soluble acetone and kneads it with a mixture of small quantities of alcohol and a camphor substance of high boiling point for instance methyl acetanylide in methyl-alcohol, which dissolves the acetylene-cellulose at first in considerable excess. A moderate heating should be applied during the reaction. contd. | ||