(A) Oxygen: oxygen in the rubber O-ring with the rubber molecule free group chain reaction, molecular chain cracking or excessive crosslinking, resulting in changes in the function of the rubber O-ring. Oxidation is one of the important reasons for the aging of rubber O-rings.
(B) Ozone: the chemical activity of ozone is much higher than that of oxygen, and the damage is greater, which is also to crack the molecular chain, but the effect of ozone on rubber varies with the deformation of rubber. When used as a rubber for deformation (mainly unsaturated rubber), cracks appear in the direction of direct stress action, that is, the so-called "ozone cracking"; When acting on the deformed rubber, only the surface of the oxide film is formed without cracking.
(C) Heat: the advance temperature can cause thermal cracking or thermal crosslinking of rubber O-rings. But the basic action of heat is still activation. Advance the oxygen dispersion rate and the activation oxidation reaction, and then accelerate the rubber oxidation reaction rate, which is a universal aging appearance - hot oxygen aging.
(D) Light: The shorter the light wave, the more energy. The damage to the rubber O-ring is caused by high energy ultraviolet rays. In addition to directly causing the cracking and crosslinking of rubber molecular chains, ultraviolet rays cause free groups to occur due to the absorption of light energy, triggering and accelerating the oxidation chain reaction process. The external light acts as a heating agent. Another characteristic of the use of light (unlike heat) is that it is mainly produced on the surface of the rubber. The sample with high rubber content will have a network crack on both sides, that is, the so-called "optical outer crack".