【国外标准】 Standard Test Methods for Rubber Deterioration-Dynamic Ozone Cracking in a Chamber (Withdrawn 2007)

The significance of these tests is mainly in their ability to differentiate, in a comparative sense, between different degrees of ozone resistance under the limited and specified conditions of the accelerated tests. These test methods may not give results correlating exactly with outdoor exposure tests or service performance since the correlation of accelerated ozone tests with such performance is highly dependent upon the specific conditions of both the accelerated ozone and outdoor exposures. Conditions that influence the accelerated tests are ozone partial pressure, air flow, temperature, stress-relaxation, and the bloom of additives. Outdoor or service performance is influenced by such weather conditions as rainfall, ambient temperature, sun light, and the strain cycles imposed.1.1 These test methods are used to estimate the cracking resistance of vulcanized rubber exposed under dynamic strain conditions to a chamber atmosphere containing ozone at a fixed partial pressure. The effect of sun or ultraviolet light is excluded. 1.2 These test methods are not applicable to materials ordinarily classed as hard rubber, but are adaptable to molded or extruded soft rubber. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.