Heat‐damaged evaluation of virgin hair

Abstract

Summary Background Hair‐straightening treatments may involve the use of thermal devices, which potentially cause damages in the cuticle and cortex of the hair fibers. Particularly, the heat causes denaturation of the α‐keratin and the degradation of the components of the hair cortex. Objectives The aim of this study was to evaluate the effect of heating on the cuticle and cortex of the Caucasian and Asian virgin hair by using heat iron flat. Methods The effects of the heating in the tresses of Caucasian and Asian virgin hair were analyzed by thermogravimetry/differential scanning calorimetry‐Fourier transform infrared/mass spectrometry (TG/DSC‐MS/FTIR), protein loss analysis (PLA), Fourier transform infrared (FTIR‐ATR), and scanning electron microscope (SEM). Results TG/DSC‐MS/FTIR results were: formation of the H2O between 25‐170°C and CO2, SCO and H2S from 200°C. Denaturation temperature = 237°C. Protein loss: Asian hair>Caucasian hair. Data presented statistically significant alterations, α = 5, P ≤ 0.05, n = 3. FTIR‐ATR: changes in the secondary structural conformation of the protein of hair cuticle. SEM: heat caused damage to hair cuticle. Conclusions The results evidenced the importance of the control of temperature in the procedures involving heat. The damage caused by thermal devices showed be dependent of the ethnicity analyzed (Caucasian and Asian hair).

Hair styling procedures and hair morphology: A clinico-microscopic comparison study

“…Experimental studies have shown that exposure of heat (either through thermal devices or atmospheric heat) may result in the denaturation of alpha-keratin and change the structure of the hair cuticle. [ 26 27 28 ] These changes may differ according to the ethnicity of individuals; this is due to the difference in anatomical structure and hair composition in these ethnic groups. For example, Asian hair is circular, has a higher number of cuticle layers, and is compact compared with Caucasian hair.…”

“…For example, Asian hair is circular, has a higher number of cuticle layers, and is compact compared with Caucasian hair. [ 27 29 ] Furthermore, even though the chemical composition is similar in different hair types, African hair has less moisture. [ 29 30 31 ] Though, in general, alternate heat and wet cycles result in cracks in hair cuticle; the loss of protein and changes in the cuticle were more in the Asian hair compared with the Caucasian hair.…”

“…[ 29 30 31 ] Though, in general, alternate heat and wet cycles result in cracks in hair cuticle; the loss of protein and changes in the cuticle were more in the Asian hair compared with the Caucasian hair. [ 27 ] Any damage to proteins may reduce water absorption and retention in hair; thus, altering the cosmetic appearance of hair. [ 32 ] Thus, it is quite likely that the same instrument at the same temperature and same procedure may have different effects on different hair types, and potentially, the damage may be higher in Asian hair.…”

Prevention of chemically induced hair damage by means of treatment based on proteins and polysaccharides

“…9 It can cause the denaturation of the α-keratin and the degradation of the hair cortex components. 10 The weakening of the fiber occurs as the rearrangement of the disulfide bonds leads to structural damage, protein loss, 8 and decrease in tensile strength. 11,12 The bleaching process is intended to induce extensive breakdown of the hair pigments, pheomelanin, and eumelanin.…”

Efficient Hair Damage Detection Using SEM Images Based on Convolutional Neural Network

“…For example, Coroaba A et al [1] used scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and other physical and chemical methods to identify the effects of alopecia areata on the structure and composition of human hair. Lima et al [2] used a heating iron to heat hair and observed hair images under a scanning electron microscope to evaluate the damage to the epidermis and cortex of the hair fiber by heat loss. Although these manual methods use scanning electron microscope imaging technology to analyze hair microscopic images, they do not perform detailed quantitative classification of hair damage.…”