Stabilizing agent
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In chemistry a stabilizer is a chemical which tends to inhibit the reaction between two or more other chemicals. It can be thought of as the antonym to a catalyst. It can be also a chemical that inhibits separation of suspensions, emulsions, and foams.

Some kinds of stabilizers are:

• antioxidants, preventing unwanted oxidation of materials
• sequestrants, forming chelate complexes and inactivating traces of metal ions that would otherwise act as catalysts
• emulsifiers and surfactants, for stabilization of emulsions
• ultraviolet stabilizers, protecting materials, especially plastics, from harmful effects of ultraviolet radiation
  • UV absorbers, chemicals absorbing ultraviolet radiation and preventing it from penetrating the materials; principially the same as sunscreens
  • quenchers, dissipating the radiation energy as heat instead of letting it break chemical bonds; often organic nickel salts, e.g. nickel phenolates
  • scavengers, eliminating the free radicals formed by ultraviolet radiation; often hindered amine light stabilizers (HALS)

See also

• Corrosion inhibitor

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