Heat: Increasing the temperature can cause thermal cracking or thermal crosslinking of the rubber. However, the basic function of heat is also activation. Increasing the oxygen diffusion rate and activating the oxidation reaction, thereby accelerating the oxidation reaction rate of the rubber, which is a common aging phenomenon - heat Oxygen aging.
Light: The shorter the light wave, the higher the energy. The higher the energy of the ultraviolet light that destroys the rubber. In addition to directly causing the breakage and cross-linking of the rubber molecular chain, the rubber generates free radicals due to absorption of light energy, triggering and accelerating. Oxidation chain reaction process. Ultraviolet light plays a role in heating. Another characteristic of light action (different from thermal action) is mainly in the surface of rubber. Samples with high gel content will have mesh cracks on both sides, so-called " The outer layer of light is cracked."
Oxygen: Oxygen in the rubber with the free radical chain reaction of the rubber molecule, the molecular chain breaks or excessive cross-linking, causing the change of rubber properties. Oxidation is one of the important reasons for rubber aging.
Mechanical stress: under the repeated action of the mechanical stress of the conveyor belt and the frictional process from the idler, the rubber molecular chain will break to form a free radical, trigger the oxidative chain reaction, form a chemical process, mechanically break the molecular chain and mechanically activate the oxidation process. Which Can dominate, depending on the conditions in which it is located. In addition, stress can easily cause ozone cracking.
Moisture: There are two aspects to the effect of moisture: when the rubber is exposed to rain or immersed in water, it is easily destroyed. This is because the water-soluble substances and water-clearing components in the rubber are extracted by water, hydrolyzed or absorbed. The cause, especially the alternating action of water immersion and atmospheric exposure, will accelerate the destruction of the rubber. However, under certain circumstances, the water does not have a destructive effect on the rubber, and even has the effect of delaying aging.
The chemical activity of ozone and ozone is much higher than that of oxygen, and it is more destructive. It also breaks the molecular chain, but the effect of ozone on rubber varies with the deformation of rubber. The rubber used for deformation is mainly unsaturated. In the case of rubber), a crack perpendicular to the direction of stress is applied. When the so-called "ozone cracking" acts on the deformed rubber, only the outer surface forms an oxide film without cracking.
Other: The factors affecting rubber are chemical media, variable metal ions, high energy radiation, electricity and biology.