What does permanent waving solution do to the hair?
- Breaks disulfide bonds by a reduction reaction
- Rebuilds disulfide bonds by an oxidation reaction
- Coats the cuticle with a conditioning polymer
- Breaks peptide bonds by a hydrolysis reaction
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A. Breaks disulfide bonds by a reduction reaction
Waving solution is a reducing agent: it adds hydrogen to the disulfide bonds and breaks them so the hair can take the shape of the rod. Rebuilding the bonds by oxidation is the job of the neutralizer.
Reference: Permanent waving: reduction reaction
What is the main reducing agent in alkaline (cold) waves?
- Hydrogen peroxide
- Sodium hydroxide
- Ammonium thioglycolate
- Glyceryl monothioglycolate
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C. Ammonium thioglycolate
Alkaline or cold waves use ammonium thioglycolate and process at room temperature without added heat. Glyceryl monothioglycolate is the reducing agent in true acid waves.
Reference: Permanent waving: types of permanent waves
True acid waves use which main reducing agent, and what do they usually need in order to process?
- Ammonium thioglycolate, at room temperature
- Glyceryl monothioglycolate, with added heat
- Sodium hydroxide, with a neutralizing shampoo
- Hydrogen peroxide, with a plastic cap only
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B. Glyceryl monothioglycolate, with added heat
True acid waves use glyceryl monothioglycolate (GMTG), have a lower pH and process more slowly, so they normally need heat. Ammonium thioglycolate at room temperature describes an alkaline (cold) wave.
Reference: Permanent waving: types of permanent waves