Stabilizer (chemistry)
Stabilizers are chemical compounds that are added to a metastable system in order to prevent the transition to a lower energy state. These transformations are mainly triggered by increased temperature, oxygen or UV rays. Stabilizers for plastics are of particular economic importance .
Applications
chemistry
Plastics have with heat stabilizers against heat and UV stabilizers to protect against the harmful effects of light. Even emulsions are stabilized by appropriate materials. Heat stabilizers are mainly required for objects made of polyvinyl chloride , i.e. for construction products such as window profiles, pipes and cables. Light stabilizers such as Hindered Amine Light Stabilizers (HALS) are particularly needed for products made from polypropylene or polyethylene . Stabilizers for plastics can be controversial for environmental reasons, as they contain heavy metal compounds. In Europe, cadmium stabilizers were no longer sold from 2001 onwards, stabilizers with toxic lead were and are increasingly being replaced by other types, for example calcium-zinc stabilizers.
In chemistry, the shelf life of synthetic chemicals, which tend to polymerize under the influence of light and atmospheric oxygen, is significantly improved or made possible by so-called radical scavengers . Such radical scavengers react with the radicals faster than the substance to be protected and interrupt the radical chain reaction that leads to polymerization. The substances used as radical scavengers are usually phenols , for example hydroquinone monomethyl ether MEHQ, 4- tert- butylpyrocatechol or 3,5-di- tert -butylpyrocatechol .
When labeling hazardous substances, the difference between “stabilized” and “not stabilized” plays a role in the case of some actually harmless substances that are classified as hazardous substances as powders or dust: Al, Cd, Mg, Zn, Zr. The term "phlegmatized" is also used here.
personal hygiene
In personal care products such as shampoos, foam stabilizers such as Cocamide DEA (a fatty acid diethanolamide) are used. In products such as sun protection cream, emulsion stabilizers are added to prevent the oil and water phases from separating.
See also
Individual evidence
- ^ Lead stabilizers
- ↑ Market study stabilizers by Ceresana Research , May 2011.
- ↑ Ingredients of shampoos
- ↑ Emulsion stabilizers in cosmetics ( Memento of the original from January 26, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
