Mechanical Properties of Kenaf Mat Reinforced Composites

Kenaf fiber is well known as a cellulosic source with both economic and ecological advantages and has been extensively exploited over the past few years. In this paper, kenaf mat as reinforcement and unsaturated polyester(UP) as matrix were used to fabric kenaf/UP by hand lay-up and compression molding methods. Mechanical properties of kenaf/UP, such as tensile properties and bending properties were investigated and discussed, as well as the low cycle fatigue (LCF) behavior. After the test, the fracture cross sectional observations were carried out on the selected test specimens using a scanning electron microscope (SEM), with a focus on the fracture morphologies. The results showed that for both un-notched and notched kenaf/UP, tensile strength decreased when the preset load was increased to 70% and 85%, and both can not survive from the LCF test of 30 cycles. In the observation of SEM, more fibers were split into several small fibers when the pre-set load was increased to 70% and 85%. When referred to the SEM observation of notched specimen, fiber fracture within the characteristic distance, most of the fiber was breakage near the fracture surface which was caused by high concentrated stress at the edge of the hole. On the other hand, bending results had shown similarity of tendency in low fatigue bending test as tensile results.