Impact of distinct alkaline treatment on natural plant fibre reinforced polymer composites

Abstract

The primary goal of this research work is to enhance the mechanical behaviour of luffa, coir and sisal fibre reinforced polymer composites, which had undergone diverse chemical processing. The selected green fibres were subjected to a variety of alkaline treatments at varied concentration of 5% NaOH, 3% KOH and 7% Ca(OH)2 for 4, 2 and 6 h, respectively. The hand lay-up method was used to prepare the nine distinct samples. It was found that the composites with highest wt.% of coir and luffa fibres which underwent NaOH treatment resulted in highest tensile strengths of 10.946 and 14.425 MPa. However, Ca(OH)2 treatment proved to be better for composites containing 20% sisal fibres. Similarly, 20% NaOH treated coir fibre reinforced composite exhibited better flexural stress and modulus, whereas Ca(OH)2 treatment led to increase in flexural stress and modulus for composites containing 20% sisal fibres. The impact strength of the composites containing highest percentage of coir fibres that is, 20% was higher for all alkali treatments. Composite containing 20% NaOH treated coir fibres exhibited maximum interlaminar shear strength. Overall, NaOH treatment of coir, Ca(OH)2 treatment of sisal and KOH treatment of luffa fibre significantly improved the mechanical behaviour of the composites.