Final answer:
The main ingredient in a permanent waving solution is ammonium thioglycolate, which breaks and reforms the disulfide bonds in hair to create lasting waves or curls.
Step-by-step explanation:
The Main Ingredient in Permanent Waving Solution
The primary chemical responsible for the permanent waving process is known as ammonium thioglycolate. This substance acts as a reducing agent, which reduces and disrupts the disulfide bonds within hair keratin. These bonds are responsible for the strength and structure of the hair.
During a perm, hair strands are first wrapped around rollers or curlers. Then, the ammonium thioglycolate solution is applied, penetrating the hair shaft and breaking down the disulfide bonds that hold the hair's natural shape. This allows the hair to take on the shape of the rollers. Once the hair has been reshaped, an oxidizing agent such as hydrogen peroxide, commonly known as the neutralizer, is applied to the hair. This agent serves to re-form the disulfide bonds, locking the hair into its new curly or wavy structure.
The process of permanent waving is distinct from temporary waving, which involves disrupting hydrogen bonds through water absorption when hair gets wet, making it flexible to styling. These hydrogen bonds can reform when the hair dries, thus setting the temporary shape until the next wash. Permanent waves, however, alter the hair's chemical structure internally and can last until the hair grows out.
In summary, the use of ammonium thioglycolate followed by a neutralizer changes the hair's shape by breaking and reforming the crucial disulfide bonds that give the hair its strength and elasticity, thus creating a lasting wave or curl.