Changes in the mechanical properties of human hair under various conditions

• Main Author: Boo, Khee Meng.
• Other Authors: Chou Siaw Meng
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/40442
• Institution: Nanyang Technological University

This project sought to investigate the tensile properties of human hair when subjected to specific conditions which is hair coloring and exposure to chlorine. Hair samples from 10 individuals of the Chinese population was randomly collected The Scanning Electron Microscopy (SEM) was used to obtain the cross sectional dimensions of the hair fiber. Five strands of hairs from each individual were used for measurements. The strands of hair were all cut across from the middle of the sample and the readings were taken. The hair samples were first washed with aqueous sodium lauryl sulphate and dried under room temperature. To prepare the hair sample for coloring, commercial dye was applied onto the hair strands. The hair sample was then washed with shampoo and left to dry in room temperature. For exposure to chlorine, the hair sample was soaked in prepared chlorine solution for an hour after which it was washed with shampoo and left to dry in room temperature. Paired-difference test was used to analyze the data statistically. The results showed that there was significance difference (P < 0.05) for maximum load and ultimate tensile stress when comparing normal hair with all the specific condition. There was also a significance difference for strain at break when comparing normal to chlorine exposed hairs. However there was no significance difference (P > 0.05) when comparing the strain at break for normal and dyed hair. There was a significance difference for modulus of elasticity when comparing normal to dyed hair whereas no significant difference was observed for modulus of elasticity between normal and chlorine exposed hair.