Outward appearance is no longer optional requirement for people in contemporary society and has been recognized as part of individuals' competitive edge. People are making unsparing investment in managing their outward appearance to satisfy their indi...
Outward appearance is no longer optional requirement for people in contemporary society and has been recognized as part of individuals' competitive edge. People are making unsparing investment in managing their outward appearance to satisfy their individual's desire to present outward beauty to others. Hair is an important element in appearance enhancement, while chemical treatments which have been increasingly applied every day for improvement of external appearance cause damage to the hairs.
Under those circumstances, this study was intended to examine the measures that could minimize the damage to the hairs in case of heat permanent procedure after hair dyeing or bleaching.
To explore the measures that could mitigate hair damage based on comparative analysis of the extent of damage by varying intermediate processing methods in softening process during heat permanent procedure using the pH balance and pH shampoos which are widely used currently at beauty and cosmetology industrial sites, we performed the procedures as below:
The dyed hairs and bleached hairs were classified into D and B, respectively. We used 4 different washing methods such as lukewarm water wash(M), lukewarm water wash(PM) after pH balance coating, pH shampoo wash(PS), and pH shampoo wash(PPS) after pH balance coating, for digital perm procedure. The results were as follows:
We measured the thickness of hair. The results showed that thickness of virgin hair stood at 0.029 ± 0.001 ㎜. The group treated by pH shampoo wash(DPPS) after pH balance coating showed the thickest strands of dyed hairs in experiment group.
In the bleached hairs, the group that underwent pH shampoo wash(BPPS) after pH balance coating showed the thickest hair strands with 0.032 ± 0.001 ㎜ in experiment group. Based on the results of moisture retention measurement in hair, virgin hair had the moisture retention of 90.76%. In the dyed hairs, moisture content in DPPS group was found to be 82.53%.
The water content in bleached hairs treated by BPPS reached 78.65%, the highest level. Water content was high in experiment group that underwent pH shampoo wash after pH balance coating in both dyed hairs and bleached hairs.
Based on the tensile strength measurement of the hairs, virgin hair was found to have a tensile strength of 119.72 ± 11.37 gf/㎟. Tensile strength of hairs treated by DPPS and BPPS was 100.68 ± 15.32 gf/㎟ and 97.29 ± 12.56 gf/㎟, respectively, suggesting that the hairs in experiment group treated by pH shmpoo wash after pH balance coating exhibited a tensile strength closest to that of Virgin hair. The results of observation of hair cuticles showed that cuticle layers were reduced due to overlapping of cuticles because the cuticles became thinner after physical and chemical treatment of heat perm in dyed hairs, the control group treated by DM. By contrast, the cuticles of hairs treated by DPM, DPS, and DPPS showed regular clearance and the shape closest to that of virgin hair cuticles. However, scaling, exfoliation, and peeling of cuticles were observed. The thickness of cuticles in bleached hairs was found to be damaged further in overall way, compared to the dyed hairs. This was considered attributable to chemical damage caused primarily by bleaching and physical damage caused by heat of perm. Based on results of observation of fine structures in hairs, the cuticle lifting of virgin hair stood at 449.48 ± 18.90 ㎚. The cuticle lifting was found to have been reduced in overall way in the experiment group of dyed hairs treated by DPPS. The cuticle lifting was 430.97 ± 22.47 ㎚, the highest, which was the closest to the cuticle lifting of virgin hair.
The cuticle lifting in bleached hairs treated by BPPS was the closest to that of virgin hair in experiment group. Although relatively thick lifting was found during the measurement, cuticle surface became thinner in overall way and partially serious exfoliation was observed. Such damage was caused in the process of oxidation and decomposition in hairs as the concentration of hydrogen peroxide increased during the bleaching procedure. The repeated washing during the procedure is considered to have caused cracks and breaks on cuticle surface.
Based on the results of observation of surface roughness of the hairs, the roughness in dyed hairs of control group treated by DM stood at 132 ㎚, showing rough and irregular shapes in overall way.
The roughness of the hairs in experiment group treated by DPS stood at 122 ㎚, the lowest level in experiment group, which represented a reduction by 10 ㎚ compared to the control group treated by DM. Observed with topographic image, cuticle clearance became widened and grooved, but cuticles had clear scale contours. The 3D images and line graphs showed that there was some damage. However, the scales with relatively regular patterns were observed. The roughness of bleached hairs in the control group treated by BM stood at 164 ㎚ which was relatively high. 3D images and line graphs showed severe curvatures. The roughness in experiment group treated by BPS was 128 ㎚, the lowest in the experiment group, and was decreased by 36 ㎚ compared to the control group treated by BM. Based on observation with topographic image, cuticle clearance was found to have been widened, and furthermore, grooved cuticles were observed. The observation with 3D image and line graph showed that the end of cuticles was exfoliated partially, but had relatively regulars scales.
The results of this study suggested that hair damage was mitigated when pH balance and pH shampoo were used together in case that the hairs underwent intermediate treatment during the softening process as part of heat perm link procedure after the dyeing and bleaching procedures. Such results are expected to provide good basic data for industrial sites in the period ahead. In addition, aforesaid results of this study will provide the basis for application that can minimize hair damage.