Antioxidants are a class of chemical substances that, when present in only a small amount in the polymer system, can delay or inhibit the oxidation process of the polymer, thereby preventing the aging of the polymer and prolonging its service life, also known as " Anti-aging agent". Substances that can delay or prevent the oxidation or auto-oxidative process are called antioxidants. The United States Food and Drug Administration (FDA) defines the so-called antioxidants as "the substances that delay the deterioration, rancidity, or discoloration caused by oxidation. substance". Antioxidants must be added to prevent rancidity of oil and grease food, to prevent viscosity change and precipitation of petroleum products such as gasoline and lubricating oil, and to prevent aging of polymers such as plastics, rubber and synthetic fibers.

  Antioxidants can slow down the automatic oxidation reaction rate of polymer materials. In addition to being used in plastics and rubber, antioxidants are also widely used in petroleum products, grease and food industries to prevent the acidity and viscosity of fuel oil and lubricating oil from rising and increasing. Rancidity of fats, meat and feedstuffs.