Effect of hydrazine post-treatment on natural fibre reinforced polymer composites

Surface modified natural fibres have received great attention due to their several advantages such as non-toxic, low cost and environmentally friendly nature. The development of composite materials, surface modified natural fibre used as reinforcing filler and thermoplastic polymers as matrixes is currently at the centre of attention. In the present work, coir fibre reinforced polypropylene composites were manufactured using a single screw extruder and an injection moulding machine. Raw coir fibre was oxidised, and manufactured composites were post-treated with phenylhydrazine in order to increase the interfacial adhesion between the coir fibre and the polypropylene matrix. Both raw and oxidised were utilised during manufacturing. Coir fibre at 15, 20, 25, 30 and 35 wt-% was utilised. Microstructural analysis (scanning electron microscopy and Fourier transform infrared spectroscopy), mechanical tests (tensile, flexural and impact, hardness) and Water adsorption property were conducted. Post-treated specimens yielded better mechanical properties compared to the oxidised and raw ones. Based on fibre loading, 30% fibre reinforced composites had the optimum set of mechanical properties. Authors propose that the bonding between the polypropylene matrix and the phenylhydrazine treated coir fibre must be improved in order to have better mechanical properties at higher fibre content.