ABSTRACT
This chapter reviews the developments on long-term protection of rubbers against aerobic aging, especially on long-term protection against ozone. It summarizes most developments with emphasis on longterm antioxidant as well as antiozonant protection. The most prevalent approach to achieve nonstaining ozone protection of rubber compounds is to use an inherently ozone-resistant, saturated backbone polymer in blends with a diene rubber. Degradation by oxygen and ozone proceeds via different chemical mechanisms and results in different effects on the physical properties of rubber. Oxygen degradation results in hardening or softening throughout the rubber article. The relatively low-molecular weight (MW) antioxidants have undergone an evolutionary change towards higher-MW products with the objective to achieve permanence in the rubber polymer, without loss of antioxidant activity. The most common test used to study the oxidation resistance of rubber compounds involves the accelerated aging of tensile dumbbell samples in an oxygen-containing atmosphere.
