Some kinds of stabilizers are:
* antioxidants these prevent autoxidation of materials and come in 3 primary forms.
** Oxygen scavengers (primarily phosphite esters such as tris(2,4-di-tert-butylphenyl)phosphite) are commonly used during the initial processing of the plastic.
** Persistent radical scavengers prevent or slow the photo-oxidation of polymers. Traditionally these are alkylated phenols such as butylated hydroxytoluene but now also include hindered amine light stabilizers (HALS)
** Antiozonants prevents or retards the degradation of polymers caused by ozone (ozone cracking)
* sequestrants, forming chelate complexes and inactivating traces of metal ions that would otherwise act as catalysts
* ultraviolet stabilizers are used to protect polymers from effects of ultraviolet radiation and come to 2 main types.
** UV absorbers which essentially act the same way as sunscreens
** Quenchers, which dissipate the radiation energy as heat instead of letting it break chemical bonds; often organic nickel salts, e.g. nickel phenolates