1. The role of light
The damage to the rubber sealing ring material is the higher energy ultraviolet light. Because of its short light wave and high energy, the damage to the sealing ring is the most direct.
In addition to the direct rupture and cross-linking of the rubber molecular chain caused by ultraviolet rays, the rubber generates free radicals due to the absorption of heat energy in the light, thereby initiating and accelerating the oxidation chain reaction process in the rubber seal ring.
Another feature of light is that it is mainly carried out on the surface of the rubber sealing ring, so net-like cracks will appear on both sides of the sealing ring with high glue content.
2. Oxidation reaction
Oxygen undergoes free radical chain reaction with rubber molecules in the saddle tee rubber sealing ring material, and the molecular chain is broken or excessively cross-linked, causing changes in the properties of silicone rubber products.
3. The role of ozone
The chemical activity of ozone is much higher than that of oxygen atoms. It is more destructive to the saddle tee rubber seal ring. It also breaks the molecular chain, but the effect of ozone on the seal ring material changes with the rubber. It's different. The larger the deformation, the larger the cross-sectional area of the reaction, the more obvious the reaction, and the faster the aging of the sealing ring.
4. Factors of high temperature
Increasing the temperature can cause thermal cracking or thermal cross-linking of the saddle tee rubber sealing ring, but the basic function of heat is still activation. Increase the oxygen diffusion rate and activate the oxidation reaction, thereby accelerating the rubber oxidation reaction rate, which is a common aging phenomenon, that is, thermal oxygen aging.
5. Mechanical stress
Under the repeated action of mechanical stress, the molecular chain of the saddle tee rubber sealing ring will be broken to form free radicals, which will trigger the oxidation chain reaction and form a mechanochemical process. Mechanical breaking of molecular chains and mechanical activation of oxidation process. Secondly, it is easy to cause ozone cracking under stress.