Mechanical properties of treated Kenaf (Hibiscus cannabinus) polyester composite at different alkaline concentration

Increase of awareness among people has increased the demand for green products. Other synthetic materials such as plastic and fibreglass has been reduced because of the environmental concern. Reinforcement with other green materials such as lignocellulosic materials has been done to reduce the dependency on synthetic material. Kenaf (Hibiscus cannabinus L.) fibres have the biggest potential to be used as a composite product and also as reinforcement in the composite products. Lignocellulosic materials including kenaf face some of problems when used as a reinforcement material with synthetic materials especially plastic based materials such as polypropylene and polyester. This problem is related to the properties of the fibres and the synthetic materials thus would reduce the mechanical properties of the product manufactured. Modification of the surface by solution treatment has been the popular method for improving the mechanical properties. In this study modification using Sodium Hydroxide or NaOH at three different concentration has been conducted to investigate the influence on the mechanical properties in terms of elasticity and strength properties of the composite material manufactured. The polyester composites were manufactured and tests according to ASTM D790-02 for bending test. Six replications of each type were tested and the values were evaluated using statistical analysis software. All the samples for both MOR and MOE showed significant differences for each type. Based on the result the highest value of the polyester composite was the kenaf that treated with 3% of NaOH solution for both MOR and MOE value.