What are the reasons that affect rubber aging?

1. Oxygen: Oxygen reacts with rubber molecules in free radical chain reactions, causing chain breakage or excessive cross-linking, resulting in changes in rubber properties. Oxidation is one of the important causes of rubber aging.

   
   

2. Ozone: Ozone is much more chemically active and destructive than oxygen. It also breaks the molecular chain, but the role of ozone in rubber depends on whether the rubber deforms. When used for deforming rubber (mainly unsaturated rubber), cracks in the direction of stress will occur, known as "ozone cracking"; When used to deform rubber, only the surface forms a non cracking oxide film.

3. Heat: Increasing the temperature can cause thermal decomposition or cross-linking of rubber. But the basic function of heat is activation. Thermal oxidative aging is a common aging phenomenon, which aims to increase the oxygen diffusion rate of rubber, activate the oxidation reaction of rubber, and thus accelerate the oxidation reaction rate of rubber.

4. Mechanical stress: Under repeated mechanical stress, rubber molecular chains break and form free chains, leading to oxidative chain reactions and the formation of mechanochemical processes. The mechanical fracture and activation oxidation process of molecular chains. Where it can dominate depends on the conditions it relies on. In addition, it is easy to cause ozone cracking under stress.

5. Moisturizing: Water has two functions: rubber is prone to breakage when exposed to rain or prolonged immersion in water in humid air, as the water-soluble substances and hydrophilic groups in rubber are extracted with water and caused by hydrolysis or absorption. Especially under the alternating effects of water immersion and atmospheric exposure, rubber damage will accelerate. However, in some cases, moisture has no destructive effect on rubber and even has the effect of delaying aging.

6. Oil: When in contact with the oil medium for a long time during use, the oil will penetrate into the rubber and cause expansion, leading to a decrease in rubber strength and other mechanical properties. Oil can cause rubber to expand because it penetrates into the rubber, causing molecular diffusion and altering the network structure of vulcanized rubber.

Other factors that affect rubber include chemical media, variable metal ions, high-energy radiation, electricity, and biology.