Thermoanalytical characterization study of hair from different ethnicities

A characterization study of the samples of hair and animal keratin was performed to enhance the understanding of the thermal properties of the hair of the main ethnic groups. The mechanical, physicochemical and thermal properties of Caucasian, Oriental and African-ethnic hair have been widely described; however, this research adds knowledge about the thermal and analytical properties of these types of hair. To achieve such objective, thermogravimetry (TG), differential scanning calorimetry (DSC) and elemental analysis techniques were employed. To estimate the thermal stability of the hair samples, TG carried out a non-isothermal TG method kinetic study. The results obtained of TG/DTG showed similarity between the samples of hair and animal keratin, for all the events of thermal decomposition involved with mass loss. African-ethnic hair sample presented the lower thermal stability. This fact can be related to the data literature that showed that this type of ethnicity has the less tensile strength and breaks more easily than others types of the hair. Oriental hair sample showed to be, from the non-isothermal TG method kinetic study, more thermally stable than the other samples. DSC results showed that the hair samples presented melting/denaturation of the crystalline phase; however, animal keratin sample did not present such.