Impact strength, microstructure, and water absorption properties of kenaf/polyethylene terephthalate (PET) fiber-reinforced polyoxymethylene (POM) hybrid composites

Natural fiber composites are becoming more attractive for applications as energy absorbers in the automotive industry despite their high moisture absorption characteristics. The main objective of this paper is to study the impact strength and moisture absorption properties of long fiber and short fiber hybrid composites using a kenaf/polyethylene terephthalate fiber reinforced in the polyoxymethylene matrix. The results obtained from the impact test gave 10.8 J/cm for the longer fiber hybrid composites, which is higher compared to 8.0 J/cm obtained for the short fiber hybrid composites due to less fiber pullout from the matrix. A moisture content of 0.92% and percentage water absorption of 6.77% were obtained for the long fiber composite due to poor interfacial adhesion between the fiber and the matrix. A high void content of 0.52% and porosity of 1.21% also accounted for high water and moisture absorption of the long fiber hybrid composite.