Mechanical, Microstructural and Thermal Characterization of Epoxy-Based Human Hair–Reinforced Composites

TLDR: In this paper, the authors used human hair (HH) fibers in the field of composites and revealed the systematic methodology of fabricating HH with polymers using the wet hand lay-up technique.

Abstract: Owing to their biodegradable nature and cost-effectiveness, natural fibers have attracted the attention of various material scientists. One such fiber is human hair (HH), which is viscoelastic-plastic in nature and encloses well-characterized microstructures within it. An important aspect is that a strand of HH having a diameter of 60 μm is capable of withstanding a force of 100–150 grams/fiber. However, wastage of HH on an enormous scale poses an environmental challenge. Therefore, the authors have utilized this novel fiber in the field of composites and revealed the systematic methodology of fabricating HH with polymers using the wet hand lay-up technique. The diverse compositions of polymer-HH composite, with varying HH weight percentages (wt.%) of 5, 6, 7, 8, 9, and 10 %, were put to investigation. In the present work, treatment of HH with potassium hydroxide and curing of polymer further enhanced the bonding properties of composites. The specimens were examined micro-structurally through scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) tests, followed by the mechanical tests: tensile, compression, flexural, hardness, and impact. Both the microstructural and mechanical tests complemented each other and confirmed that the cured polymer composite speckled with 7 wt.% of HH fiber content was the best of all formulations, as it provided the highest magnification in mechanical properties relative to neat polymer. Finally, the thermal analysis was done via thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) techniques.