Antioxidants, Polymers

Abstract

Organic matter is subject to decomposition, particularly through reaction with oxygen. This leads to several reactive secondary products such as hydroperoxides and peroxy and alkoxy radicals. Antioxidants are used to slow down oxidative degradation by reacting with these reactive intermediates. On the one hand, this article explains the mechanism of the oxidation of polymers and, on the other hand, describes suited antioxidants and their influence on the stabilization of polymers during their processing in the melt and during their service life. Suitable antioxidants, including combinations of antioxidants, which act as free‐radical scavengers (primary antioxidants) and hydroperoxide or peroxide scavengers (secondary antioxidants), are explained. Traditional commercial antioxidants still play a role when used in industrially manufactured polymers. Moreover, the stabilization of polymer recyclates against oxidative degradation is gaining in importance. Furthermore, in recent years, unconventional antioxidants of natural origin have also increasingly come into focus. Methods for the analytical determination of antioxidants in polymeric substrates are also described, with which the consumption and effectiveness of these products can be examined.