Effect of Kenaf Fibre Mat Layer on mechanical and water absorption properties of Kenaf reinforced unsaturated polyester composites

This study focused on the preparation of kenaf fibre reinforced unsaturated polyester composite through the compressing molding technique. The composite characterizations in flexural properties, water absorption and thickness swelling test. Besides, morphological properties have been conducted and analyzed in order to further the evaluation. The Water absorption test was carried out for seven days and measurement were made every day to calculate the water absorption and thickness swelling of the samples. Flexural test revealed that the incorporation of multiple layers of kenaf mat into UPE resulted in the increase of flexural strength and modulus. Nevertheless, the UPE alone still showed superior flexural strength since the presence of natural filler/fibre in polymer tends to reduce strength properties. Meanwhile, water absorption test found that, UPE/ZKF has absorbed more water and cause higher thickness swelling compared to the UPE and others composite formulations due to the hydrophilic nature of natural fibre. Morphological studies were done by using high magnification microscope and field emission scanning electron microscopy. The results proved that the optical micrograph of composite surface does not show any changes in morphology, but UPE revealed the formation of microcracks. Thus, it has been noticed that the fiber fracture, fiber debondings and holes are some of the defects, which are observed due to the application of the load on the specimen. Kenaf fibre reinforced unsaturated polyester composite was successfully prepared. The increase of fibre contents results in higher strength and modulus, increase water absorption and thickness swelling properties. Besides, shows the good morphological properties of the composites.