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A heat-assisted ammonium thioglycolate permanent waving system

  • Ammonium thioglycolate is an organic ammonium salt having thioglycolate(1-) as the counterion. Also known as perm salt, it has use in perming hair. It has a role as a reducing agent and an allergen. It contains a thioglycolate.
    Thioglycolic Acid is an organic compound that contains a thiol group (-SH) and carboxylic acid. It is a colorless liquid. Thioglycolic Acid and some salts and esters of Thioglycolic Acid, such as Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Glyceryl Thioglycolate, Isooctyl Thioglycolate, Isopropyl Thioglycolate, Magnesium Thioglycolate, Methyl Thioglycolate, Potassium Thioglycolate and Sodium Thioglycolate are used in hair coloring products, permanent wave products, hair straightening products and depilatory products.
    Ammonium thioglycolate solution can be used in the synthesis of:
    Thiol functionalized eggshell membrane applicable as adsorbent material for the removal of Cr(VI), Hg(II), Cu(II), Pb(II), Cd(II), and Agfrom aqueous water.[1]
    Cellulose-rhodamine B methacrylamide (cellulose-RhBMA).[2]

    It can also be used as a reagent to reduce disulfide bonds in keratin.
    A heat-assisted ammonium thioglycolate permanent waving system is provided in which heat-containing clamps applied to the hair to assist the action of the ammonium thioglycolate bring the hair up to hair waving temperature and maintain it at such temperature for no more than six minutes and in which the ammonium thioylycolate solution is weaker than is used in non-heat-assisted permanent waving for the same type of hair and stronger than has been used in prior heat-assisted permanent waving for the same type of hair.
    An ammonium thioglycolate solution contains a lot of free ammonia that swells up the hair and makes it more permeable.
    Ammonium thioglycolate, also known as perm salt, is the chemical compound with the formula HSCH2CO2NH4.

    Being the salt of a weak acid and weak base, ammonium thioglycolic acid exists in solution as an equilibrium mixture of the salt itself as well as the free carboxylic acid thioglycolic acid (HSCH2CO2H) and ammonia:

    HSCH2COO− + NH4+ ⇌ HSCH2COOH + NH3
    A solution containing ammonium thioglycolate contains a lot of free ammonia, which swells hair, rendering it permeable. The thioglycolic acid in the perm solution reduces the disulfide cystine bonds in the cortex of the hair. In a sense, the thioglycolate removes crosslinks. After washing, the hair is treated with a mild solution of hydrogen peroxide, which oxidizes the cysteines back to cystine. These new chemical bonds impart the structural rigidity necessary for a successful perm. The rigidification process is akin to the vulcanization of rubber, where commonly polysulfide linkages are used to crosslink the polymer chains. However, not as many disulfide bonds are reformed as there were before the permanent. As a result, the hair is weaker than before the permanent was applied and repeated applications over the same spot may eventually cause strand breakage.

    In the 2001 film Legally Blonde, law student Elle Woods wins her first case by her knowledge of the chemistry of ammonium thioglycolate (which she pronounces "ammonium thyglocolate"), something she claims "any Cosmo girl would have known."