Previous report showed that proteins and amino acids were dissolved from bleached hair. This study was carried out to determine the affects of permanent-waving agent on the dissolution of proteins from hair, breaking point and waving effect.
Dissolution of proteins into permanent-waving agent was measured as previously reported. Breaking points of hair treated by permanent-waving agent were evaluated by the tensile tester after treatment by oxidizing agent for 15 minutes. The waving effect was measured by the method of kirby.
The higher pH of the permanent-waving agent, the more dissolved proteins from hair. Breaking points of hair were decreased at higher pH. The waving effect increased as the rise of pH, but it decreased at pH 10. On the contrary, the amount of dissolved proteins from hairs and the breaking point were slightly influenced by the treatment time.
It is noteworthy that the amounnt of dissolved proteins and breaking point gave a good correlation. From these results, the analysis of dissolved proteins from hair to evaluate hair damage was suggested to be important. Permanent-waving agent gave damage to hair greately, and it was confirmed that much proteins dissolved in the short time. Most of dissolved one was seemed to be peptides or proteins but not to be free amino acids.