Antioxidant is a kind of plastic additives that can effectively reduce the self-oxidation reaction speed of plastic materials and delay its aging degradation. It has a wide range of applications and is widely used in various polymer material products. Plastic antioxidants are generally based on phenols, phosphorus, sulfur auxiliary antioxidants, metal ion passivators, etc., and their application types and dosages mainly depend on plastic materials, processing techniques and usage. Oxidants can be classified according to their functions (main antioxidants, auxiliary antioxidants, autologous carbon-based capture agents).

The antioxidant properties are as follows:

1. Synergy:

The synergistic effect of amine antioxidants and phenolic antioxidants with peroxide decomposers is well known, and they can improve the heat resistance, oxidation resistance and anti-aging properties of materials. Scott et al. proposed the concepts of uniform coordination and inhomogeneous coordination between molecules, and combined the two to discuss the inhomogeneous coordination between molecules. Uniform synergy is the synergy between two compounds with the same mechanism but different activities, while non-uniform synergy is the synergy between two or more antioxidants with different mechanisms. This kind of internal coordination of molecules is called "self-synergy", which is a kind of stabilizer that contains multiple functional groups that cooperate with each other.

The results show that the use of phenolic antioxidants and sulfur antioxidants at the same time has a better long-term antioxidant effect. Phosphorus antioxidants can decompose hydrogen peroxide and are mainly used as antioxidants during processing. The processing stability is also different when the processing temperature is different. Phosphorus antioxidants are used at normal processing temperatures (close to 200°C). Under high temperature conditions, phosphorus antioxidants and phenolic antioxidants are used at the same time. Phenolic antioxidants can capture hydrogen peroxide. Therefore, it can make the phosphorus antioxidants more stable and play a synergistic effect. For example, if organic phosphoric acid is used in the polymerization inhibitor phenolic antioxidant at the same time, the amount of free radicals captured will be greatly increased.

2. The impact of the conflict:

Some antioxidants can produce harmful effects when used in combination, which is the antioxidant effect. Hindered amines are alkaline, incompatible with thiopropionic acid, and exhibit obvious antagonistic effects. The polysulfide compounds and certain antioxidants in the rubber also have a certain antioxidant effect. Secondary aromatic amines and hindered alkyl phenols are effective composite antioxidants, but polyethylene containing carbon black (ultraviolet shielding agent) is added. Because the surface of carbon black has a catalytic oxidation effect on amine or phenolic antioxidants, The anti-oxidation effect of adding carbon black is poor.