Mechanical properties of kenaf fibre reinforced urea formaldehyde resin composites

Composite materials, in general, are used in the industry because of their positive qualities such as optimized performance, minimized weight and volume, cost effectiveness, chemical and biodegradation resistance. The main purpose of this research is to find the best particleboard by using low cost materials. The research in this thesis is focused on kenaf fibre with adhesive of low emission Urea Formaldehyde resin with 51.6% solid content. The fabrication process for UF fibres boards is based on wood particle that makes the fabrication simple and economical. Boards with the densities of 500kg/m3 and 600kg/m3 were chosen based on the standard wood particleboards. Kenaf fibres of two different sizes and various fibre weight fractions (90wt%, 85wt%, 80wt%, 75wt% and 70wt %) were used in the fabrication of kenaf UF composite boards. The specimens were subjected to different mechanical tests such as impact test, internal bonding test, screw test, bending test, tensile test and water absorption test. The fabrication of the particleboards was done using hot press for 6 minutes under the pressure of 40 Ton at 180°C for different fibres weight fractions with different sieving sizes of fibres and densities. The results demonstrates that the samples with higher density yields the higher value of modulus of rupture, modulus of elasticity, tensile strength, Young's modulus, screw test, impact test and internal bonding. The findings also demonstrate that the level of density affects the performance of a board, where the board with low density will result in low mechanical strength as compared to the boards with higher density. Types of raw materials and phenol formaldehyde resin were also investigated through different tests to identify the properties of the fabricated boards. The obtained results show that the higher tensile and bending strength values were achieved at 80wt% regardless of the fibres size. Besides, the results shows that the highest values for modulus of rupture MOR and modulus of elasticity MOE for 1mm and 0.6mm fibres size were achieved at 80wt%. While the optimum impact strength was founded to be at 85wt% for 1mm fibres size and at 80wt% for 0.6mm. Screw and internal bonding tests show that 80wt% at 1mm fibres size provides the highest value among other possible options.