Which bonds are broken and reformed during a permanent wave?

Which bonds are broken and reformed during a permanent wave?

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

Answer: (B)

Disulfide bonds are the key cross-links that set hair’s curl. In a permanent wave, a reducing agent breaks these sulfur-sulfur bonds in the keratin of the hair, allowing the strands to be reshaped around rods. Then a neutralizer oxidizes and reforms new disulfide bonds in the hair’s new configuration, fixing the curl. Hydrogen bonds can be temporarily disrupted by water and heat but they’re not what creates a permanent change, so they don’t provide lasting structure. Ionic bonds and peptide bonds aren’t the targets of perm chemistry; breaking peptide bonds would damage the hair, and ionic bonds aren’t the bonds altered to hold the new shape.

Disulfide bonds are the key cross-links that set hair’s curl. In a permanent wave, a reducing agent breaks these sulfur-sulfur bonds in the keratin of the hair, allowing the strands to be reshaped around rods. Then a neutralizer oxidizes and reforms new disulfide bonds in the hair’s new configuration, fixing the curl. Hydrogen bonds can be temporarily disrupted by water and heat but they’re not what creates a permanent change, so they don’t provide lasting structure. Ionic bonds and peptide bonds aren’t the targets of perm chemistry; breaking peptide bonds would damage the hair, and ionic bonds aren’t the bonds altered to hold the new shape.