Mechanism of Action of Hindered Amine
What has been found out as yet about how the hindered amine light stabilizers work suggests that a number of different reactions are responsible for the stabilizing effect they have on photooxidation. Proof has been found of the radical entrapment qualities of carbon radicals, the reaction of HALS metabolites with peroxy radicals and the decomposition of hydroperoxides.
An acidified hindered amine cannot easily enter into the free radical scavenging cycle.
N-H and N-R hindered Amine Stabilizers fit most needs regarding light stability but can be alkaline.
N-OR type enter the UV stabilization cycle quickly and are much less alkaline than N-H or N-R type of HALS.
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