In the process of using nylon conveyor belt, it is easy to cause the aging and shedding of the rubber layer. After research, the factors that cause the rubber aging are as follows:
1) Oxygen: Oxygen undergoes free radical chain reaction with rubber molecules in the rubber, and the molecular chain is broken or excessively cross-linked, causing changes in rubber properties. Oxidation is one of the important reasons for rubber aging.
2) 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 whether the rubber is deformed or not. When used as deformed rubber (mainly unsaturated rubber), cracks that are perpendicular to the direction of stress action appear, so-called "ozone cracks"; when acting on deformed rubber, only an oxide film is formed on the surface without cracking.
3) Heat: Increasing the temperature can cause thermal cracking or thermal crosslinking of rubber. But the basic function of heat is activation. Increase the oxygen diffusion rate and activate the oxidation reaction, thereby accelerating the rubber oxidation reaction rate, which is a common aging phenomenon-thermal oxygen aging.
4) Light: The shorter the light wave, the greater the energy. The damage to the rubber is the higher energy ultraviolet rays. 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 light energy, which initiates and accelerates the oxidation chain reaction process. Ultraviolet light plays a heating role. Another characteristic of light action (different from heat action) is that it mainly grows on the surface of the rubber. For samples with high gel content, network cracks will appear on both sides, the so-called "light outer layer cracks".
5) Mechanical stress: under repeated action of mechanical stress and continuous friction process with the roller, the rubber molecular chain will be broken to generate free radicals, which will trigger oxidation chain reaction and form a mechanochemical process. Mechanical breaking of molecular chains and mechanical activation of oxidation process. Which one can have the advantage depends on the conditions. In addition, it is easy to cause ozone cracking under stress.
6) Moisture: Moisture has two effects: rubber is easily destroyed when exposed to rain or immersed in water. This is because the water-soluble substances and clear water groups in the rubber are extracted and dissolved by water. Caused by hydrolysis or absorption. Especially under the alternating action of water immersion and atmospheric exposure, it will accelerate the destruction of rubber. However, under certain circumstances, moisture does not have a destructive effect on rubber, and even delays aging.
7) Others: There are chemical media, variable metal ions, high-energy radiation, electricity and biology that affect rubber.
