Phosphites

Rostabil organophosphites like triphenylphosphite (TPP) and trisnonylphenylphosphite (TNF) are secondary antioxidants. They decompose hydroperoxides into non-reactive species, slowing polymer oxidative degradation. Primary and secondary antioxidants, used alone or together, maintain polymer performance integrity and improve color and processing stability.

Antioxidants significantly slow down oxidative degradation caused by free radicals from heat, UV light, or impurities. Unstabilized polymers degrade, losing mechanical properties due to decreased molecular weight, discoloration, and brittleness. Hindered phenols and aromatic amines, called primary antioxidants, donate reactive hydrogen to peroxy radicals, preventing further radical propagation.