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A summary of the nature and special applications of the more important types of synthetic rubbers is given. Two series of rubber and synthetic rubber stocks, compounded on the basis of comparable pigmentation, were selected for study. In addition to the conventional physical properties (tensile strength and elongation at rupture, modulus, aging, etc.), a number of other mechanical properties such as dynamic rigidity, hysteresis loss, ``blowout resistance,'' ``running temperature,'' and tensile strength at elevated temperature were measured. Swelling tests in various solvents were also made. Results are plotted in the form of correlation charts in an effort to select proper methods of measurement. Some observations on comparative service tests in tires in the case of three synthetic rubbers indicate them to be satisfactory, on a quality basis, for use in time of emergency. The importance of care in selecting the proper physical tests and methods of analysis is emphasized in the light of the results given. It is concluded that rubber testing techniques and interpretation must be modified in certain instances in evaluating synthetic rubber stocks.
Street et al. (Wed,) studied this question.