Effects of NaOH treatment and NaOH treatment conditions on the mechanical properties of coir fibres for use in composites manufacture

The influences of NaOH treatment and NaOH treatment conditions (NaOH concentration, treatment temperature and duration) on the mechanical properties of coir fibres were examined. The experiment was designed on a Minitab Software with a view to determining the optimal NaOH treatment conditions that would reveal the variable(s) that exerted the most significant influence on the tensile properties of the NaOH-treated coir fibres. NaOH treatment brought about increase in the tensile strength of coir fibres. The highest tensile strength and Young’s modulus were observed at the same treatment condition of; 20% NaOH concentration, 24 h duration and at 50 °C. Pareto Chart confirmed concentration as the parameter that exerted the highest influence on the material’s tensile properties. Observations from the microstructure showed that removal of tyloses was more as a result of treatment temperature and duration than NaOH concentration. The microstructure of the NaOH-treated coir fibres showed rough surfaces which can lead to improved adhesion between the fibres and the matrix during composites manufacture, thus improved mechanical properties of the composites.