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).
Page detailing chemical analysis procedures for materials, likely paper, including tests for sizing, mineral ash, and nitrogenous content.
| Identifier | ExFiles\Box 24\2\ Scan243 | |
| Date | 30th January 1923 guessed | |
| 664 DIRECTIONS FOR THE STUDY OF Cut up 30 to 40 grammes of the dried sample into pieces, weigh off duplicate lots of 10 grammes each, introduce each into a one-quarter litre flask, and add to each 200 cc of distilled water. Boil for 20 minutes, decant the solution through a perforated disc, wash each lot of paper twice with 75 cc of warm water. Titrate filtrates, using methyl orange indicator. If the indicator shows the solution to be alkaline, titrate (neutralize) it with a standard centinormal solution of sulphuric acid: N/100 H2SO4 If the indicator shows the solution to be acid, titrate (neutralize) it with a standard centinormal solution of sodium hydrate: N/100 NaOH or potassium hydrate: N/100 KOH In each case the number of cubic centimetres of the reagent required to neutralize the paper shall be stated. (c) Mineral Ash Test. About 25 grammes of the dry sample obtained from the determination of moisture test shall be very completely ignited with all precautions against loss. The residue of incombustible mineral matter (ash) shall be weighed, and the amount computed as a percentage of the weight of the dried sample. (d) Sizing Tests. (i) Resinous Material. The total resins in the size shall be determined as follows:— Five grammes of the paper shall be cut into strips about ¼ inch wide and folded into numerous small cross-wise folds. These shall be placed in the siphon cups and acidulated alcohol (900 cc of 95 per cent alcohol, 95 cc distilled water, and 5 cc glacial acetic acid) shall be poured into the cup until it starts to siphon over. When this has entirely siphoned over into the shell-shaped extraction flasks, approximately 200 cc more of the acidulated alcohol shall be added to the siphon cup which is then connected to the condenser. The flask shall be set into a steam bath and the extraction shall proceed for about 2 hours, or until the cup has filled and siphoned over about ten times. The extract shall be poured into a weighed glass dish and the flask washed out with a small portion of the acidulated alcohol, which is added to the original extract. The alcohol shall then be evaporated and just before the extracted total resins in the glass evaporating dish go to dryness, they shall be cooled, taken up with 25 cc of ether, and transferred to a 250 cc separatory funnel containing 100 cc of distilled water and 25 cc of a saturated solution of sodium chloride, the latter being present to prevent the formation of an emulsion. The funnel shall be shaken thoroughly and the contents allowed to separate. The water shall be drawn off into a second separatory funnel, and washed again with 25 cc of ether. The two ether extracts shall be combined and washed two or three times with 100 cc of distilled water to remove all the salt and foreign matter other than ether-soluble resins. Should glue, which is extracted from the paper by the alcohol, interfere by emulsifying with the ether it may be removed readily by adding a strong solution of sodium chloride to the combined ether extracts, shaking thoroughly and draining it off, repeating, if necessary, before washing with distilled water. The washed extract shall be transferred to a weighed glass dish, evaporated to dryness slowly, dried in an oven at 95° C. (203° F.{Mr Friese}) to 100° C. (212° F.{Mr Friese}) for one half-hour, cooled and weighed. The increase in weight of the dish divided by 5 and multiplied by 100 will give the percentage of total resins. (ii) Nitrogenous Material (Glue and Casein). The total nitrogenous material in the size shall be determined by the Kjeldahl-Gunning method described in Atack's Chemists' Year-book, 1921 edition, page 130, as follows:— “ About 1 gm of the paper is cautiously treated in a long-necked resistance flask with about 20 cc of conc. sulphuric acid (excessive frothing must be avoided). The heating is continued until the frothing subsides and then the flask is allowed to cool. (The nitrogen has been converted into ammonium sulphate.) Ten gm of potassium sulphate and a crystal of copper sulphate are added and the flask again heated until the contents are of a pale-green colour. Cool and dilute with 500 cc of distilled water. One hundred cc of 30 per cent caustic soda are carefully poured down the side of the flask, avoiding mixing with the acid. The flask is connected with the acid absorption apparatus, the contents of the flask shaken up and the liberated ammonia distilled into excess N/10 acid. This is back titrated with N/10 caustic soda and the ammonia titration calculated to nitrogen. A blank test must be carried out.” If no casein be present the percentage of nitrogen obtained multiplied by 5·6 will give the percentage of glue in the sample of paper. Note.—This test is of no value for the determination of the percentage of glue when glue and casein are present, since both contain nitrogen. 9. CHEMICAL TESTS FOR METALLIC PARTICLES.* The following tests shall be carried out on three samples of paper, each not less than one foot square, * The hydrochloric acid in test (a) has a tendency to act upon the iron oxides present, thus producing considerable discoloration of the paper. Test (b) does not readily disclose the presence of copper and brass particles. Test (b) detects iron, copper and brass particles, but it is not sufficiently penetrating, especially when testing dark paper, and metallic particles well inside the sample may not be disclosed. Also after a short time the discoloration extends throughout the sample, thus causing difficulty in detecting the metallic particles. Test (c) does not indicate the metallic oxides. | ||