Published: Jan 1958
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Early in 1957 a plan was outlined by the Ozone Test Section of Subcommittee XV of ASTM Committee D-11 on Rubber and Rubber-Like Materials for an Interlaboratory Test Program. This program's main objective was to determine the degree of variation that existed among laboratories with nominally identical ozone test chambers when testing specimens prepared and cured from a single rubber mix. There were also several secondary objectives. Since the advent of the first industrial ozone test chamber (Crabtree-Kemp), two later chambers have appeared. The first -was the Bush chamber and more recently the Mast chamber. Both of these feature the forced air circulation that has been demonstrated as necessary for valid and meaningful tests. Both of these chambers were included in this test program, and a comparison between the two is possible. This is one of the secondary objectives. Another objective was to determine how well various laboratories could maintain a given ozone concentration for a period of several days. In designing the testing program, a compromise had to be made between obtaining sufficient data for valid statistical interpretation and the need for keeping the testing load at a reasonable level. Some preliminary experimental work in these laboratories indicated that specimens with varying resistance to ozone attack would be valuable. It was decided that this could be best accomplished by employing different rubbers rather than by additives (antiozonants) added to a single rubber. Accordingly, SBR (GRS), neoprene, and butyl rubbers were selected. Typical formulations of these were prepared and used for testing.
Veith, A. G.
Chairman, B. F. Goodrich Research Center, Brecksville, Ohio