Abstract
The effects of the chemical and mechanical treatment conditions on the permanent wave performance of hair tresses treated with a proposed waving procedure modified by the incorporated relaxation process in the conventional waving technique were investigated. The evaluation of the shape of the waved samples was performed in dry state after one day. As compared to the results obtained with the conventional technique, all of the tresses of reduced for 3 and 5 minutes with the appropriate range of pH and concentration in the ammonium thioglycolate(ATG)solution were superior in wave strength and stability with increasing both pH and ATG concentration in reducing solution. This effectiveness is caused by some rearrangement of the protein chains in the stress-supporting phase in the hair and dependent on the proportion of ionized sulfhydril groups(KS-)generated by the cleavage of the disulfide bonds. It was found, in addition, that the effectiveness of relaxation process was also dependent on the degree of initial stress wrapped on the rod. These findings indicate that in the proposed waving procedure modified by the incorporated relaxation process, both concentration of KS- in the reduced area within the hair and degree of the initial bending stress wrapped on the rod are the main factor of the permanent wave formation of human hair. Accordingly the incorporation of relaxation process to the conventional technique brought the shortening of the reducing and neutralizing process at the completion of the permanent waving procedure. The shortened reducing and neutralizing process brought about decrease in the damage caused by the reduction and oxidation reaction, resulting in major benefits as observed by appearance and feel.
