Effects of Alkali-Silane Treatment on Tensile Strength of Woven Kenaf Reinforced Polypropylene Composites

Natural fibre reinforced plastics (NFRP) had been developed by researchers all over the world nowadays because natural fibre offers a lot of advantages such as low cost and does not threat the environment over glass and carbon fibres. However, limitations occur in order to produce the NFRP in mass due to the limited adhesion or bonding between the matrix and fibre which caused the reduction of their mechanical properties. The main reason behind the lack of bonding is because of their difference in nature, matrix being hydrophobic and fibre is hydrophilic in nature. Therefore, in this paper surface treatment had been done on the woven kenaf fibre. The fibre had been treated with 5% concentration of NaOH solution for 24 hour at room temperature. Then, the woven kenaf is being washed with tap water and 1% concentration of acetic acid in order to neutralise the remaining NaOH on the fibre. Then the kenaf is dried in the oven at 45oC for 12 hours. Next, the kenaf is immersed in a mixture of 5% of the fibre weight of three-aminopropyltriethoxysilane solution, 50% aqueous solution of methanol, and 1 % concentration of acetic acid for 4 hours at 28oC. The fibre is then washed and dried in the oven for another 12 hours at 45oC. The processing method used in order to produce the composite is compression moulding technique. The composites are being processed at 185oC under 10 tons of compression force. the tensile strength of the woven kenaf increased about 62% when compared to neat PP alone. However, slight decrement in tensile strength of the treated composite compared to untreated composite. Based on the FESEM analysis done, it could be seen that the decrement was due to the deterioration of the woven kenaf fibre maybe because being damp for too long.