Antioxidants are a class of chemical substances that can delay or inhibit the oxidation process of polymers when they exist in only a small amount in the polymer system, thereby It prevents the aging of polymers and prolongs their service life, also known as “anti-aging agent”.
Antioxidants can be divided into primary antioxidants, auxiliary antioxidants and metal antioxidants. Auxiliary antioxidants can be divided into phosphorus antioxidants, thioether antioxidants, and metal purifiers. Today, Kaiyin Chemical will take you to understand the phosphorus antioxidants among the auxiliary antioxidants:
The biggest feature of phosphorus antioxidants is that they have a synergistic effect with phenolic antioxidants. In the anti-oxidation process, phenolic antioxidants capture peroxide free radicals and then produce hydroperoxides (hydroperoxides can automatically undergo thermo-oxidative aging reactions), but phenolic antioxidants cannot decompose hydroperoxides, and phosphorus Antioxidants can decompose hydroperoxides, thereby inhibiting the thermo-oxidative degradation of plastics.
In addition, phosphorus antioxidants can also improve the color stability of materials and the weather resistance of products:
Plastic products are easily discolored by ultraviolet rays, and the discoloration of plastic additives is much greater than that of the resin itself. Since phenolic antioxidants produce stable phenolic oxygen free radicals, they lead to the accumulation of colored products, thereby discoloring plastic products. Phosphorus antioxidants can reduce the oxidized phenolic oxidants and turn them into colorless or white compounds, thereby improving the color stability of the material.
If the stability of the plastic is not good during processing, the hydroperoxide accumulated in the product will become an initiator of photoaging degradation, which is not conducive to improving The weather resistance of the product, and the combined use of phosphorus antioxidants and light stabilizers can improve the weather resistance of the material.