Items that affect the aging of rubber O-rings A) Oxygen: Oxygen is reflected in the free radical chains of rubber O-rings and rubber molecules, and the molecular chains are cracked or excessively cross-linked, resulting in changes in the function of rubber O-rings. Chemical action is one of the key reasons for the aging of rubber O-rings. (B) Ozone: The chemical activity of ozone is much higher than that of oxygen, and it is more destructive. It opens the molecular chain, but whether the effect of ozone on rubber is different from the deformation of rubber. As a kind of rubber (mainly unsaturated rubber) used for deformation, it cracks directly in the direction of stress action, that is, the so-called“Ozone Cracking”; When acting on deformed rubber, it only produces oxide film on the surface without cracking. (C) Heat: The forward temperature will cause thermal cracking or thermal crosslinking of the rubber O-ring. But the heat-based effect is still an active effect. Pre-oxygen loosening rate and active oxidation reaction followed by accelerated rubber oxidation reaction, a common aging appearance——Thermo-oxidative aging. (D) Light: The fewer the light waves, the greater the kinetic energy. The higher kinetic energy of the UV rays destroys the rubber O-rings. In addition to directly causing the cracking and cross-linking of the rubber molecular chain, the rubber will also generate free radicals due to the absorption of light energy, thereby causing and accelerating the reaction process of the oxidation chain. Heated by external light. Another characteristic of light action (different from thermal action) is that it occurs mainly on the rubber surface. Samples with high glue content will have mesh cracks on both sides, the so-called“photofissure”.