Objective: A Kenaf composite was prepared by using hand lay-up process. The effect of weather on mechanical, morphology and thermal properties of kenaf composite was studied. Method: Tensile strength of kenaf composite was found to be 60 MPa. Unfortunately, tensile strength of the composite started decreasing after the first weathering month which continued throughout the weathering periods with constant reduction of tensile, reducing almost 85% of the composite mechanical behaviour at the end of the weathering period. Result: The resulting mechanical properties obtained clearly showed that natural fiber and its composites are not able to stand environmental condition because they have poor wettability, incompatibility with some polymeric matrices and high moisture absorption. Due to the high moisture absorption properties, there are formations of void in the composites which can reduce the mechanical properties of composite such as flexural strength or flexural modulus clearly supported by SEM results. Conclusion: It was found that the degree of moisture absorption increased as the exposure time increased. The tensile and flexural properties of kenaf fiber were found decreasing due to moisture induced degradation and the degradation was significant after 2 months. Fortunately, some modifications can be done for improving the mechanical properties, thus, integration of zinc nano particle is proposed; the water repellent capability is good enough to achieve the high performance of the composite with proper system formulation during the modification process and the result of Zinc nano particle reinforced kenaf fiber was shown to have prevented the degradation of the composite.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

Polyester/kenaf composites reinforced with zinc oxide nanoparticles (ZnO NPs) were fabricated. The nanoparticle treatment had a noticeable effect on the mechanical properties of the composites. Kenaf treatments with five different concentrations 1%, 2%, 3%, 4%, and 5% were performed. The mechanical analysis showed an increased flexural strength stability and break elongation in the functionalized ZnO NPs-treated kenaf polyester resin composites. The polymer nanocomposites with 2% ZnO NPs had stable mechanical properties with moderate elastic properties compared with the remaining ZnO NPs systems. The mechanical properties of the composites that contained different layers of kenaf mat demonstrated positive influence on the polymer nanocomposites. The material increased in stiffness with an increase in layers from 1 to 5. The results of weathering confirmed the stability of the polymer nanocomposites with increased stability. The 2% nanoparticle coating with a 5-layer kenaf layer revealed no remarkable changes in the mechanical degradation throughout the 6-month weathering period. The results of the mechanical properties tests suggested that a 2% ZnO NPs concentration with five kenaf layers had the highest moisture resistance, thus; the ZnO NPs acted as a water repellent agent.

In this research, unsaturated polyester/kenaf fiber (UP/KF) composites was prepared by using hand lay-up process. The effect of surface treatment of kenaf fiber on mechanical properties of kenaf filled unsaturated polyester composites were studied. Different concentrationsof stearic acid (SA) were applied, i.e. 0, 0.4, and 0.8 wt%. The Fourier transform infrared (FT-IR) spectra of kenaf fiber shows high intensity of the peak around 3300-3400 cm-1 , which is attributed to the hydrogen bonded O-H stretching. However, the treated kenaf fiber with stearic acid shows the elimination of O-H group and this peak is vanished. This is due to the reaction of (-COOH) group of stearic with (-OH) group of kenaf fiber. The results of water absorption study revealed that increasing the loading of KF in the composite will result is increasing the tendency to absorb water. However, the absorption was significantly decreased after treatment with stearic acid as well as the time to reach to the equilibrium state. 1.Introduction Recently, there is a drastic growing attention in utilization of natural fibers materials as reinforcingcomponent in thermoplastics as well as thermosets.Natural fibers seem to be a superior material which has emerged as an abundant and sustainable replacement for the nonrenewable and expensive synthetic fibers. The advantages of naturalfibres overtraditional reinforcing materials such as lower density, less abrasiveacceptable specific strength and stiffness, greater deformability and less irritation to skin and respiratory [1].Several natural fibers have been used as a reinforcement in composites materials for advanced applications such as banana, sisal, oil palm, jute, kenaf and coir. Among different types of fibers, kenaf fiber has been widely explored over the past several years [2]. Kenaf (Hibiscus cannabinus, family MalvaceaeL.) is a perennial plant herb. Kenaf is a plant heatseason annual lane and can be used for several industrial applications. Kenaf fiber has several The

In this research, we prepared pure kenaf composites and kenaf/glass fibre hybrid composites using the hand lay-up procedure. Also, we studied the weather effects on the mechanical, morphological and thermal properties of the pure kenaf and the kenaf/glass fibre hybrid composites. Before the weathering conditions, we determined that the tensile strength of the kenaf /glass fibre hybrid composite was 70.9 MPa, while the tensile modulus was 3030 MPa. However, during the first weathering month, there was a decrease in the tensile modulus values, which further decreased as the weathering continued. Also, there was a significant difference in the tensile modulus reduced values between the pure kenaf and the glass fibre-reinforced kenaf composites, which indicated that the glass fibre was a good reinforcement option, and could be successfully used for producing high performing composites. Based on the flexural strength results obtained, it could be noted that the natural fibre composites could not withstand the environmental conditions, as they displayed poor wettability, a higher moisture adsorption and were incompatible with some of the polymeric matrices. As they had higher moisture absorption properties, they formed voids within the composites that could decrease the composite mechanical properties like the flexural strength or the flexural modulus, which was supported BY our SEM results. However, some of the modifications do tend to improve the mechanical properties, which help in improving the composite performance with a proper composite formulation during modification. Our results showed that the thermal properties of the kenaf and the kenaf hybrid composites are significantly affected by the weather, wherein the composites display a slow and gradual initial weight loss till a massive weight loss was observed at temperatures around 390°C. However, as the weathering increased, the weight loss was seen to occur at even low temperatures of 290°C. This phenomenon was because of the moisture absorption, which was seen to increase it, and the moisture weakened the molecular interfacial bonds.