Antioxidants are a class of chemicals that, when present in only a small amount in a polymer system, can delay or inhibit the oxidation process of the polymer, thus Prevents the aging of polymers and extends their service life, also known as “anti-aging agents”.
Antioxidants can be divided into main antioxidants, auxiliary antioxidants and metal antioxidants. Auxiliary antioxidants can be divided into phosphorus antioxidants, thioether antioxidants, and metal purifiers. Today I will take you to learn about phosphorus antioxidants among auxiliary antioxidants:
The biggest feature of phosphorus antioxidants is that they have a synergistic effect with phenolic antioxidants. During the antioxidant process, phenolic antioxidants capture peroxidative 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 thermal 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 prone to discoloration under the action of ultraviolet rays, and the discoloration of plastic additives is much greater than that of resins. discoloration itself. Since phenolic antioxidants produce stable phenolic oxygen free radicals, they lead to the accumulation of coloring products, thereby discoloring plastic products. Phosphorus antioxidants can reduce oxidized phenolic oxidants and turn themselves 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 the initiator of photoaging degradation, which is not conducive to improving the weather resistance of the product, and phosphorus will The combined use of antioxidants and light stabilizers can improve the weather resistance of materials.