Some Recent Contributions to Synthetic Rubber Research

351 352 BELL SYSTEM TECHNICAL JOURNAL both from German sources and from their own researches to warrant taking the gamble. As a part of the large program laid out under the auspices of the Government in 1942, provision was made for a cooperative research and development effort to parallel and to contribute to the constructional program designed to provide the much needed rubber. A large number of company laboratories as well as universities contributed to this research. The Bell Telephone Laboratories because of its past contributions in this field of synthetic polymers was asked to participate in this program. The present discussion is intended to describe part of the Bell Laboratories investigations directed toward the improvement of Buna S type rubber, particularly work relating to the characterization and control of the final copolymer. In order to present the material in a logical and understandable form to readers unfamiliar with the subject-matter, brief mention will be made of the history of the synthetic rubber problem and of progress in the knowledge of polymeric substances during recent years. THE PROBLEM OF SYNTHETIC RUBBER