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).
The properties and applications of synthetic rubbers and rubber sponge.
| Identifier | ExFiles\Box 178\2\ img058 | |
| Date | 25th March 1940 guessed | |
| -3- We can conclude from these results that we should examine our usage of rubber in order to get greater dynamic fatigue life, or perhaps to get equal life with smaller amounts of material. I have no doubt that some of these findings will be incorporated in tomorrow's uses of rubber. Synthetics: It is of interest to note that similar effects are found in the dynamic fatigue of rubber-like materials which are now becoming of increasing importance. To what extent these materials may become our "Rubber of Tomorrow" is as yet highly speculative. It should be emphasized that they are not "synthetic rubber". Synthetic rubber would be a material produced by chemical processes which would exactly duplicate natural rubber in its chemical formula and structure. The synthetics we have now do not duplicate natural rubber but resemble it in chemical or physical behaviour. This may convey the impression that the inorganic chemist has done an imperfect job and that he is still trying to duplicate nature exactly. I should like to dispel any such misunderstanding. It now looks as though it would be much better to produce a whole range of rubber-like materials than to be able to duplicate the familiar rubber of commerce. As we are learning more and more about the ways in which large molecules can be assembled from smaller chemical building blocks we can see that what we need is not a laboratory replica of nature's rubber tree but the ability to shape specific molecules to meet specific needs. Steady progress is being made in that direction. We already have Neoprene, Thickol, and Buna, none of which is identical with rubber but each of which has specific advantages for specific applications. A typical example is where oil resistance is required. Natural rubber is rapidly swollen by many organic solvents and rubber chemists have struggled for years to reduce the oil absorbing tendency of their compounds. Here are two materials which are similar in appearance and satisfactory in most physical properties. This one is made with natural rubber (No. 5255), the other is made from Neoprene (No. 5929). A week ago we put samples like these in gasoline at a room temperature, and they are now in the condition you see in this jar. (Have glass shelf halfway down in jar). The one made from rubber has increased approx. 114% in weight; the one from Neoprene has increased only about 1/10 as much or about 12% in weight. You can readily imagine applications in which Neoprene would be entirely suitable while rubber would be hopeless. Special advantages of this type are causing a steadily increasing use of the synthetic materials in spite of a disadvantage in cost which seems likely to continue. Sponge: You are familiar with the older type of rubber sponge which has been made for years by incorporating gas-forming ingredients in the rubber compound so that during vulcanization these produce a spongy structure. | ||