Principle of Antioxidants
Polymer is exposed to harsh environment such as heat, high energy radiation, which causes the polymer to degrade. These degradation represent changes in chemical structure and molecular weight of the product, resulting in deterioration of mechanical properties. It destroys the stability of the polymer and causes discoloration and deterioration.In order to avoid such a situation, it is necessary to add an antioxidants to the polymer. There are two types of antioxidants:
Phenolic Antioxidants
Also known as primary antioxidants, it can quickly terminate the oxidation reaction, or release hydrogen atoms to form a relatively stable compound to avoid damage from peroxide radicals. It is also known as " Chain-Terminated Antioxidants ".
Phosphite Antioxidants
Also known as secondary antioxidants, or "Preventative Antioxidants". These types of antioxidants can react with hydroperoxide groups, to form stable, non-radical compounds, and it can terminate the chain oxidation reaction.
Usually Phenolic Antioxidants are used together with Phosphite Antioxidants for best results.