During a permanent wave, which type of chemical bond is primarily broken and reformed to set the curl?

During a permanent wave, which type of chemical bond is primarily broken and reformed to set the curl?

• A. Hydrogen bonds
• B. Ionic bonds
• C. Disulfide bonds
• D. Peptide bonds

Answer: (C)

The curl from a permanent wave is created by breaking and reforming the hair’s disulfide bonds. These strong covalent links between cysteine residues in keratin hold the shape of the hair, so altering them changes the curl pattern. A reducing agent first breaks the disulfide bonds to loosen the hair’s structure, allowing it to be wrapped around rods into the desired shape. After wrapping, a neutralizer restores oxidation and re-forms new disulfide bonds in the hair’s new configuration, locking in the curl. Hydrogen bonds and ionic bonds can help with temporary reshaping, but they’re easily reversed by moisture or pH changes and don’t provide the lasting curl. Peptide bonds are the backbone links in proteins and aren’t the bonds targeted in a perm.

The curl from a permanent wave is created by breaking and reforming the hair’s disulfide bonds. These strong covalent links between cysteine residues in keratin hold the shape of the hair, so altering them changes the curl pattern. A reducing agent first breaks the disulfide bonds to loosen the hair’s structure, allowing it to be wrapped around rods into the desired shape. After wrapping, a neutralizer restores oxidation and re-forms new disulfide bonds in the hair’s new configuration, locking in the curl. Hydrogen bonds and ionic bonds can help with temporary reshaping, but they’re easily reversed by moisture or pH changes and don’t provide the lasting curl. Peptide bonds are the backbone links in proteins and aren’t the bonds targeted in a perm.