Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Yeditepe University, Instıtute Of Health Scıences, Pharmacy, Turkey
Approval Date: 2019
Thesis Language: English
Student: ESSAM TÜRKMANİ
Supervisor: Yasemin Uzuner
Abstract:This study aims to investigate the penetration abilities of some natural oils into human hair and the how these oils affect hair properties. Also, the effect of repeated hair bleaching was monitored and the ability of the studied oils to restore the desired hair properties was studied. Mineral oil was used as a negative, non-penetrating, control and coconut oil as a positive, penetrating, control. Other oils used were linseed oil, almond oil and baobab oil. Hair tress used was obtained from a Turkish supplier as the same person's virgin hair and the swatches were prepared according to the test requirements in house with the help of a hair wig maker. Virgin hair swatches were bleached in the laboratory. The penetration of the oils into the hair cortex was investigated by using fluorescence microscopy after marking the oils with an oil soluble probe, nile red. Cross-sections of hair filaments were made by cutting the hair vax blocks by microtome. Penetration studies were conducted for the five oils on both virgin hair and bleached hair swatches. The effects of the oils on physical properties of the virgin and bleached hair were studied by measuring the stress at break point; tensile strength of the hair fibers. Combing forces were also measured to evaluate the effects of using the oils on the ease of combing of hair switches. Repeated combing and grooming test was also conducted to evaluate the effect of each oil on the reduction of hair breakage under harsh circumstances. Differential scanning calorimetry was also used to monitor the structural changes and chemical damage caused to hair by bleaching and the effects of penetrating oils vs. nonpenetrating oils on restoring the hair properties. And finally, the effect of oils on hair porosity and how it affects water loss from the hair was studied. Fluorescence microscopy results showed that linseed oil and almond oil were able to penetrate into virgin hair, whereas baobab oil was not. It was also noticed that when hair was bleached, all the oils were able to penetrate into the cortex, meaning that bleaching caused some real damage to the hair cuticle cells allowing the oils to get through the cuticle layer and reached into the cortex. It was also noted that the further the hair was bleached, the weaker and more prone to breakage it was getting, and application of oils onto the hair had favorable effects in almost all cases studied. Tensile strength results also showed that penetrable oils improved stress at break points for both virgin and bleached hair, whereas non-penetrable oils did not have a noticeable improvement on the stress at break point for virgin hair, but it did have an effect on bleached hair.