What is antioxidant for plastics or rubber?
All chemicals that can retard or prevent the oxidation or auto-oxidation of the polymer or
rubber is called antioxidant. Antioxidant can retard or inhibit the oxidation of the polymer
or rubber, prevent the aging of the polymer or rubber, and prolong the service life of the
polymer or rubber.
In the production processing of rubber and plastic products, if the high temperature products
are exposed to the air, the oxidation phenomenon will seriously affect the fading and embrittlement
of the products, which will affect the quality of the products. Adding an antioxidant can prevent
the occurrence of high temperature oxidation and protect color. In addition, during the use and
storage of the product, oxygen, moisture, acid gases, etc. in the air will slowly oxidize the product,
resulting in a decrease in the mechanical properties such as the strength of the product, affecting
the performance of the product. Antioxidant continues to act, blocking the oxidation process and
extending the life of the product
The principle of oxidation reaction and the working principle of antioxidant
The thermal oxidation process of organic compounds is a series of free radical chain reactions
in which the chemical bonds of organic molecules are broken under the action of heat, light or
oxygen to form active free radicals and hydroperoxides. The hydroperoxide undergoes a
decomposition reaction, and also generates a hydrocarbon oxygen radical and a hydroxyl radical.
These free radicals can initiate a series of free radical chain reactions that result in fundamental
changes in the structure and properties of organic compounds.
The role of the antioxidant is to eliminate the radicals that have just been produced, or to promote
the decomposition of the hydroperoxide and prevent the chain reaction from proceeding. Antioxidants
capable of eliminating free radicals include compounds such as aromatic amines and hindered
phenols and their derivatives, which are called primary antioxidants; antioxidants capable of
decomposing hydroperoxides are organic compounds containing phosphorus and sulfur,
called Auxiliary antioxidants.