The mechanical performance of hybrid phenol-formaldehyde-based composites reinforced with glass and oil palm fibres

Oil palm fibre was hybridised with glass fibre in order to achieve superior mechanical performance. The reinforcing effect of glass in phenol formaldehyde resin is evaluated at various glass fibre loadings. Tensile strength, tensile modulus and flexural strength increase with an increase in fibre loading. However, elongation at break and flexural modulus are found to decrease beyond 40 wt.% fibre loading. Impact strength and the density of the composites showed similar trends. Compared to the gum sample, hardness of the composites decreased by glass fibre reinforcement. The hybrid effect of glass fibre and oil palm empty fruit bunch (OPEFB) fibre on the tensile, flexural and impact response of the composites was investigated. Randomly oriented glass and OPEFB fibre mats were arranged as interlayers to enhance the hybrid effect. The overall performance of the composites was improved by the glass fibre addition. Impact strength shows great enhancement by the introduction of a slight amount of glass fibre. Density of the hybrid composite decreases as the volume fraction of the OPEFB fibre increases. Hardness of the composites also showed a slight decrease on an increased volume fraction of OPEFB fibre. Scanning electron micrographs and optical photographs of the fractured surfaces were taken to study the failure mechanism and fibre/matrix interface adhesion. The experimental results were compared with theoretical predictions. The hybrid effect of glass and OPEFB fibre was also calculated. (C) 2002 Elsevier Science Ltd. All rights reserved.