Question

Once in the cortex, the waving solution breaks the disulfide bonds through a chemical reaction called reduction. A reduction reaction involves either the addition of hydrogen or the removal of oxygen. The reduction reaction in permanent waving is due to the addition of hydrogen. The chemical process of permanent waving involves the following reactions:

A. A disulfide bond joins the sulfur atoms in two adjacent polypeptide chains.
B. permanent wave solution breaks a disulfide bond by adding a hydrogen atom to each of its sulfur atoms.
C. The sulfur atoms attach to the hydrogen from the permanent waving solution, breaking their attachment to each other.
D. Once the disulfide bond is broken, the polypeptide chains can form into their new curled shape. Reduction breaks disulfide bonds and oxidation reforms them.

Answer 1

The chemistry behind permanent waving primarily involves reducing disulfide bonds in hair's protein structure with a reducing agent and then reforming them into a new shape with an oxidizing agent.

Step-by-step explanation:

The process of creating permanent curls involves a series of chemical reactions that alter the hair's natural disulfide bonds. During permanent waving, disulfide bonds within the hair's protein structure are broken by a reduction reaction.

This is achieved by using a reducing agent, typically ammonium thioglycolate, which adds a hydrogen atom to each sulfur atom of the disulfide bond. The separated sulfur atoms then attach to the hydrogen from the waving solution, effectively breaking the bond and allowing the hair to take on a new shape around rollers or curlers.

After the hair is set in its new shape, an oxidizing agent, usually hydrogen peroxide, is applied to the hair to reform the disulfide bonds in their new configuration.

This oxidizing process ensures that the new curls are held in place permanently, lasting until the hair eventually grows out. The breaking and reforming of these bonds are key to achieving the desired curly or wavy hair texture.

It is important to note that disulfide bonds are covalent and stronger than hydrogen bonds, making them responsible for the permanent alteration of hair texture. In contrast, the hydrogen bonds that also help maintain the hair's shape can be temporarily altered by water when the hair gets wet, but this change is not permanent and reverts upon drying.