Stabilizer (chemistry)
Stabilizers are chemical compounds which are added to a metastable system, to prevent the transition to a lower energy state. These conversions are triggered essentially by elevated temperature, oxygen or ultraviolet rays. Of economic importance are particularly stabilizers for plastics.
Applications
Chemistry
Material shall be protected with thermal stabilizers against heat and UV stabilizers against the harmful effects of light. Also emulsions are stabilized by appropriate materials. Heat stabilizers are required especially for objects made of polyvinyl chloride, that is for construction products such as window profiles, pipes and cables. Particularly for products of polypropylene or polyethylene can be used light stabilizers, such hindered amine light stabilizers (HALS). Stabilizers for plastics can be controversial for environmental reasons, as they contain heavy metal compounds. In Europe, cadmium stabilizers have not been sold since 2001, with toxic lead stabilizers have been and are being replaced by other types, for example, calcium -zinc stabilizers.
In chemistry, the shelf life of synthetic chemicals that tend under the influence of light and atmospheric oxygen to polymerizations significantly improved by so-called free radical scavengers or made possible. Such radical scavengers react faster than the protected compound with the free radicals and interrupting the radical chain reaction, leading to the polymerization. The substances used as scavengers are usually phenols, for example hydroquinone monomethyl ether, 4-tert- butylcatechol or 3,5- di-tert- butylcatechol.
In the hazardous material identification, the difference plays "stabilized" or " non-stabilized" in some se harmless substances play a role, which are classified as a powder or dust as a hazard: Al, Cd, Mg, Zn, Zr. Here, the term " desensitized " is used.
Body Care
In personal care products such as shampoos, foam stabilizers such as cocamide DEA ( a fatty acid diethanolamide ) may be used. In compositions such as sunscreen emulsion stabilizers are added to prevent separation of the oil and water phase.