Dataset from the uniaxial tensile testing of human curly hair fibers under different conditions
Single curly human hair fibers were collected from one female doner at her early 30s. The hair fiber donor had no history of chemical treatment such as dye, relaxing and bleaching for at least six (6) months. Single fiber specimens were subjected to uniaxial tensile testing under different strain rates.
Steps to reproduce
2.1 Specimen acquisition and preparation The 114 specimens (N = 114) were collected from the African female individual in her early 30s to avoid the variation in mechanical properties influenced by age, gender, and ethnicity. The specimens were collected from the nape or occipital regions of the scalp as it is not too exposed to sunlight or other external environmental attacks. There was no cosmetic treatment done on the hair for the last six months, but only daily washing in water and drying was done on the hair prior to sample harvest. The specimens of 50 mm unstretched were harvested 5 mm from the scalp for morphology evaluation. The specimens without lags were 80mm in length then 25 mm lengths were removed from Both ends so that only 30 mm lengths were left for tensile testing. The specimens were washed and rinsed for ultimate cleaning and kept dry under an atmospheric state for 24hr to reach the equilibrium. Informed consent was obtained from the donor before harvesting the specimen in accordance with the study’s ethical approval granted by the University of South Africa’s Research Ethics Committee in the College of Science, Engineering and Technology. 2.2 Morphology evaluation The 20 % of the specimen were evaluated to confirm the curly profile before treatment and testing. The valuation of the specimens was classified according to their curly pattern. The wave crest assessment method adapted from the previous study was used to identify the curl type. From the harvested 50 mm unstretched specimens, only a midspan length of 40 mm unstretched specimens were available for counting the number of crests and the 5 mm lengths on both ends were used to hold the specimens in place on the measuring ruler. Upon counting the crests, it was found that 80% samples had four crests while 20% had five crests which was then concluded that the specimens fell under type VI. 2.3 Mechanical tensile testing The 20 mm single curly hair specimens (N=114) were tensile tested with the Ustretch 44N load cell as dry and wet conditions (25°C and 35°C) at the relative humidity 65% of tested under strain-rate 100.s-1,10-2. s-1 10-3. & 10-4s-1. The paper frame technique proposed by Adusumalli et al.for the clamping of single hair fibers was then modified by using the A4 papers instead of the cardboard tabs used in the literature  The lags on the specimen were removed by hand when gluing the specimen onto the paper. The fabric glue was used to glue the specimen onto the paper tabs.
National Research Foundation (NRF)