The American Synthetic Rubber Research Program

Chemistry and Industry, Nov 5, 1990 by Reg German

From condoms to rubber gloves

The American synthetic rubber research program

P J T Morris Apart from condoms, rubber gloves and hot water bottles, there are not many simple rubber products which are directly used by the general public. Almost all the other rubber products are components, which form a myriad of different black bits, and pieces attached to other products. It is little wonder, therefore, that rubber is generally regarded as being a single material existing in two forms: natural which comes from trees, and synthetic (which in the public mind is probably not as good as the natural version). The rubber industry itself is partly to blame for this view, as it spent over a hundred years developing a very wide range of products based on natural rubber with an amazing variety of additives. The strength of the industry to some extent depended on its secret black art know-how, and even in linguistic terms the industry is unique among the material industries in that it is thought of as being a product maker - for example the steel industry does not make washers, but the rubber industry does!

But for the past 50 years the game has been changing and now there are over 20 different elastomers in regular use, each with its own unique combination of properties and its own technology. Each can be compounded with a very wide range of materials to produce tailor made compounds for specific applications. Unfortunately for the image of the industry, the best reinforcing filler for most of the elastomers is still carbon black in its many forms, so the majority of rubber products come out black.

Manufacturing is also specialised and varied, including coagulation of water based latices, through reactive liquid systems, to standard mixed rubbers. Shaping and curing are carried out in a large variety of different ways. In addition most technical rubber products incorporate other materials, such as metal, plastics or textile elements. Composites are not a new buzz area for the rubber industry. The world's most developed and sophisticated composite product is the tyre. Even a simple car tyre will probably contain textile fabrics in its casing, metal wire fabrics in the breaker under the tread, wired metal beads, adhesive systems and over a dozen different rubber compounds.

Some of this specialised know-how and technology is contained in two books which are concerned with the technology of rubber. Werner Hofmann's `Rubber technology handbook' is a major reference work, packed full of facts and references for the rubber technologist, covering almost every aspect of properties, compounding, testing and general manufacturing. Its only disadvantage as a reference book is that it has a rather heavy prose style, which makes reading hard work. But it is a book which could well find a high level of acceptance both within the rubber industry and among the industry's customers.

`Elastomers and rubber compounding materials', edited by I Franta, covers much of the same ground as Hofmann, and also some other areas such as textiles. But it is a much less comprehensive book, with significant gaps in detail, and an emphasis on older techniques and materials. The book is in fact an updated version of the second Czechoslovakian edition published in 1979, but in many ways its technology is even earlier. For example, rubber reclaim, which has basically disappeared from the western scene due to its variable properties which make it unsuitable for today's highly quality controlled products, takes up 24 pages; as opposed to a half page in Hofmann.

However, neither book will provide the non specialist reader with a readable account of the industry, which will still keep its wide range of technologies fairly well hidden from the world at large.

In contrast Peter Morris's `The American synthetic rubber research program' is a very readable account of the war-time project, involving the US government, the rubber industry and academia, to produce a general purpose synthetic rubber for tyres to cover the gap in supplies which arose when the Japanese captured Southeast Asia. This well researched and referenced book covers the technology of the development, which has its own fascination. But perhaps even more fascinating are the descriptions of the organisations and of the people involved in the programme.

It looks at the project from the viewpoint of each of the players, all of whom had different objectives, different levels of willingness to cooperate, and different levels of dedication. The programme is an object lesson in how not to organise such an event, and its progress was a catalogue of the disadvantages of cooperative research programmes. But despite all its problems, it worked and the US produced 850,000t of synthetic rubber in 1945.

The main reason for success was the wartime spirit of cooperation: and one of the strangest decisions was to keep the programme running well beyond the end of the war. The programme ran until 1955, by which time the whole thing had fallen apart as personal ambitions, company profit, the `not invented here' syndrome and other elements had taken over. Peter Morris has produced an excellent analysis of the lessons to be learnt from the story. His book should be made compulsory reading for anyone involved in such multi-party research programmes.