Final answer:
Ammonium thioglycolate breaks disulfide bonds in hair during the permanent wave process, making it flexible for reshaping. After styling, hydrogen peroxide, an oxidizing agent, is used to reform these bonds, setting the hair in the new shape. Disulfide bonds are key to the hair's strength and are manipulated in both temporary and permanent waving.
Step-by-step explanation:
Ammonium thioglycolate breaks disulfide bonds by adding hydrogen. An oxidizing agent, usually a dilute solution of hydrogen peroxide, rebuilds the disulfide bonds by removing the hydrogen that was added by the permanent waving solution.
In the process of permanent waving, a reducing substance such as ammonium thioglycolate is applied to the hair. This chemical reduces disulfide bonds in the hair's keratin, allowing it to become more flexible and take on a new shape around curlers or rollers. Once the desired shape is achieved, a neutralizer, which is commonly a dilute hydrogen peroxide solution, is used. This oxidizing agent helps to reform the disulfide bonds in their new positions, setting the hair in its new style.
The alteration of disulfide bonds, which are strong covalent bonds formed by the oxidation of sulfhydryl groups on cysteine within the hair's protein structure, is essential for both temporary and permanent waving techniques. Disulfide bonds give hair its strength and texture. Temporary waves involve manipulating hydrogen bonds, which are weaker and re-form when the hair is dried into a new shape. However, for a permanent wave, the stronger disulfide bonds must be broken and reformed, resulting in a longer-lasting style.