Antioxidants

Physical blends of stabilizers with different stabilization mechanisms are the state of the art today. The overall effect of two stabilizers combined is better than what would be expected based on the sum of effects of each component alone.

Phenolic antioxidants are radical scavengers which prevent thermal degradation of many organic materials such as polymers. Their effectiveness increases when used in combination with phosphites, thioethers and light stabilizers.

Phosphites are efficient decomposers of hydroperoxides that are formed during the autooxidation of polymers. Phosphites are especially used in melt processing where they are added in blends with hindered phenolic antioxidants. Such combinations are more effective than hindered phenol alone.

Sulfur-containing antioxidants, also referred to as thioethers, react with and decompose polymer peroxide to inert substances. These so-called ‘secondary anti-oxidants’ exhibit a remarkable synergism in combination with hindered phenols to offer additional long term stability.