PSI Barbering Practice Exam

What type of bonds are broken by chemical relaxers?

1. Sulfide bonds

2. Hydrogen bonds

3. Ionic bonds

4. Disulfide bonds

The correct answer is: Disulfide bonds

Chemical relaxers primarily target disulfide bonds within the hair. Disulfide bonds are strong covalent bonds formed between the sulfur atoms of cysteine amino acids in the hair's protein structure, keratin. When a relaxer is applied, the chemical agents reduce the disulfide bonds, enabling the hair to be reshaped and straightened. Breaking these disulfide bonds is crucial for the effectiveness of the chemical relaxer, as it allows for the alteration of the hair's natural curl pattern. Once the desired shape is achieved, a neutralizing solution is usually applied to help reform the disulfide bonds in their new arrangement, thus locking in the straightened style. While hydrogen bonds and ionic bonds are present in the hair structure, they are not the target of chemical relaxers. Hydrogen bonds are weaker and can easily be broken and reformed with moisture and heat, which is why they play a role primarily in temporary styling. Ionic bonds, on the other hand, are generally involved in the overall stability of the protein structure but do not have the same direct impact on texture alteration as disulfide bonds do. Therefore, the correct understanding of the action of chemical relaxers is focused on disulfide bonds, making this the correct answer