The Effects of Sodium Carbonate and Bicarbonate Treatments on Sisal Fibre Composites

Abstract

This work investigates the effect of eco-friendly chemical treatments on the mechanical and physical properties of composite laminates based on sisal fibres. A 2²3¹ full-factorial design is conducted to test the influence of chemical solution types, fibre treatment time, and polymer matrix type on the mechanical and morphological characterisation of the composites. Chemical treatments remove impurities from fibre surfaces, and enhance fibre-matrix adhesion. The treatments, especially with sodium carbonate (Na₂CO₃), also progressively reduce the hemicellulose fibre content. Polyester composites made with sisal fibres treated with Na₂CO₃ for 96h achieve enhanced strength and stiffness under tensile, compressive and impact loads. The results evidence the feasibility and efficiency of the proposed eco-friendly treatments for natural fibres and the application of renewable fibre laminates in secondary structural applications.

Keywords:
Epoxy; polyester; sisal; sodium carbonate; sodium bicarbonate