Effect of Water Ageing on Mechanical Performance of Kenaf/PLA Bio-Composites

In present research, the effect of tap water and seawater on the properties of the kenaf/PLA composite with three different orientations (unidirectional, bidirectional, and randomly oriented) has been analyzed. Mechanical characterization (hardness, tensile, flexural and impact test) along with surface roughness test was performed after water ageing of all developed composites. The surface roughness of the composites decreased after immersion in tap water but increased after immersion in seawater. Randomly oriented kenaf/PLA had the highest increase of 66.67% after immersion in seawater, but unidirectional kenaf/PLA composite had the highest decrease in roughness of 16.67% after immersion in tap water. Decrease in hardness was most significant in bidirectional kenaf/PLA with decrease of 10.52% and 13.68% after immersion in tap water and seawater, respectively. Tensile strength decreased for both cases and the decrease in tensile strength was maximum for randomly oriented kenaf/PLA of 39.82% and 49.86% after immersion in tap water and seawater, respectively. Flexural strength decrease was maximum for unidirectional kenaf/PLA composite at 40.25% and 48.07% for immersion in tap water and seawater respectively. Similarly, impact strength reduction was also maximum for unidirectional kenaf/PLA composite of 20.71% and 26.03% for immersion in tap water and seawater, respectively. From SEM analysis, deterioration of fiber and fiber-matrix interface can be seen which plays an important role to analyze the properties of the composite.