Researchers in India have been investigating the nano tensile properties of human hair using an LFPlus single column materials testing machine and NEXYGENPlus control and analysis software from Lloyd Instruments. Using a specially designed winding grip to secure the sample, individual hairs undergo ‘pull to break’ tests to determine Young’s modulus, yield stress and tensile strength.

Human hair has an outer layer of flat scales known as the cuticle, which protects the softer inner cortex tissue. As the hair is stretched, small stress drops are seen on the tensile curves before the fibre fails completely. These initial stress drops are due to strands of the cuticle failing while the cortex remains intact. The system is being used to analyse the differences in nano tensile mechanical properties between different types of hair.
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