Abstract

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The low mechanical properties of natural fibre composites have limited their use in engineering applications, paving ways for synthetic fibres that are ecologically non-sustainable. This study is targeted at finding suitable and acceptable industrial application of kenaf natural fibres in engineering solutions via a new treatment method. Kenaf bast fibre reinforced ABS composites were developed with the purpose of reducing intrinsic high moisture absorption and improving fibre–matrix interface. Treatment of the fibres were done with sodium hydroxide solution, then coated with thermosetting epoxy resin before composite fabrication. The treated and coated kenaf fibre (ENKF), coated kenaf fibre (EKF) and natural kenaf fibre (KF) fibres were incorporated into ABS at 10 wt% constant fibre loading. Melt-mixing was done using twin- screw extruder before compression moulding at a temperature of 240 °C, pressure of 65 kg/m2 for 5 minutes. FTIR and SEM analyses were conducted on the untreated, treated and coated fibres. Mechanical properties such as three-point bending, impact, and tensile properties of the constituent ENKF/ABS, EKF/ABS and KF/ABS composites and the fracture properties were also studied with varying fibre loadings of up to 15 wt%. The results show that the coating was effective in reducing the peaks intensity for the FTIR analysis, all the properties of kenaf/ABS composites were better improved by the new surface coating treatment with epoxy resin than the NaOH treated composites with EKF/ABS composites having superior properties than ENKF/ABS composites. Both were better than KF/ABS that exhibited poor interfacial bonding leading to lower mechanical properties. The mechanical properties of the composites recorded an increase in value with increasing fibre loading up to 15 wt%. FESEM studies of EKF/ABS and ENKF/ABS revealed the absence of debonding and delamination due to coating. Kenaf natural fibre composite properties can thus be improved further by coating, finding increased applications in industrial productions

Keywords: Kenaf fibres; epoxy coating; engineering thermoplastics; ABS composites