A study on the damage of human scalp hair

Abstract

Listen

Translate article

The effects of cosmetic treatments and procedures, such as cold-waving, bleaching, brushing, combing, etc., on the damage of the hair were studied under practical conditions. The hair samples of known history were provided from 107 women aged between 15 and 59. The degree of damage of the hair was evaluated by observing cuticle scales with a scanning electron microscope (SEM). The fine structure of cold-waved and bleached hair was also examined in comparison with that of untreated, virgin hair with a transmission electron microscope (TEM). In addition, the alkali solubility test and tensile test were carried out in order to understand the changes of chemical and physical properties by varying the degree of cuticle damage.The results obtained are as follows:(1) With increasing the degree of cuticle damage, the alkali solubility was increased and the breaking stress was decreased. This shows that the hair cuticle cells play an important role in determining chemical and physical properties of the hair.(2) Bleaching, hair-dyeing, cold-waving and brushing were found to have a great effect on the increase of the degree of cuticle damage. Bleaching among chemical treatments was found fo have the greatest influence on the cuticle damage.(3) The bleached and cold-waved hair was found to show the destruction of the inner layer of cuticle cell, i.e., the endo-cuticlar layer, which leads to lifting and stripping away cuticle cells.(4) The cuticle cells were considerably stripped off by bleaching followed by brushing or combing, but the loss of cuticle scales did not generally occur without brushing or combing.From the above results, it is clear that the mechanical factors are of primary importance and they are the direct cause for stripping away of the hair cuticle. Thus, investigation on a suitable procedure of brushing and a desirable brush is important to decrease the damage of the hair by daily brushing or combing.