Research Scientist, B. F. Goodrich Research Center, Brecksville, Ohio
Pages: 9 Published: Jan 1958
The reaction of ozone with unstressed rubber and neoprene was examined by using open cell sponge. In each case the initial rate of adsorption was very high and decreased with the adsorption of ozone. Under conditions of very high humidity, however, there was no falling off in the rate of ozone up-take. The sponge was extracted with acetone and the products examined. A similar pattern was obtained on solid styrene-butadiene rubber (SBR) in a tread-type recipe. Here as the sample was elongated the amount of ozone adsorbed increased until a strain of about 20 per cent was reached. Under the conditions of the test, the ozone up-take reached a constant value at this point. The mechanism of cracking of rubber by ozone is postulated to be by modification of the rubber structure by ozone to yield a material with low elongation. Cracks then develop by failure in tension of this modified rubber. Cracks typical of ozone cracking were produced by curing the surface of rubber compounds much tighter than the interior.
Paper ID: STP46939S