Effect of Alkali Treatment on Interfacial and Mechanical Properties of Kenaf Fibre Reinforced Epoxy Unidirectional Composites

Abstract

Kenaf fibres demonstrate enormous potential in fibre reinforced composites with the excellent performance and environmental benefits. In this work, kenaf fibres were treated with NaOH at the concentrations of 1%, 2%, and 3%.Effects of the alkaline treatments on the mechanical properties of fibre and interfacial shear properties (IFSS) of the resulted composites were systematically evaluated. In addition, relationship between tensile strength and surface friction coefficient of kenaf fibre was shown. Relationship between tensile strength of fibre and IFSS of composites were explored. They were conducted by correlation analysis method. The results indicated that after NaOH treatment, kenaf fibres has increased in tensile strength, surface roughness, friction coefficient, but decreased in diameter. Tensile properties, flexural properties and water absorption of unidirectional kenaf fibre reinforced epoxy resin composites have improved. IFSS of composite treated at 2% alkali has increased by 10.34%, compared to composites untreated fibres. Correlation analysis indicated that there was no significant correlation between kenaf fibre tensile strength and IFSS of the composite. On the other hand, there was significant correlation between kenaf fibre surface friction and the IFSS of the composite with the correlation coefficient of 0.905. ABSTRAK Serabut kenaf menunjukkan potensi besar dalam pembuatan komposit diperkuat serabut disebabkan ia mempunyai prestasi cemerlang dan kesan positif kepada alam sekitar. Dalam kajian ini, serabut kenaf dirawat dengan natrium hidroksida (NaOH) pada kepekatan 1%, 2% dan 3%. Kesan rawatan alkali terhadap sifat mekanik serabut dan sifat geseran permukaan (IFSS) daripada komposit yang dihasilkan dinilai secara sistematik. Di samping itu, hubungan antara kekuatan tegangan dan koefisien geseran permukaan serabut kenaf telah dinyatakan. Hubungan antara kekuatan tegangan serabut dan IFSS komposit telah diterokai. Analisis dijalankan melalui kaedah analisis korelasi. Keputusan menunjukkan selepas rawatan NaOH 1%, serabut kenaf meningkat dalam kekuatan tegangan, kekasaran permukaan, koefisien geseran dan penurunan diameter. Sifat tegangan, sifat lentur dan penyerapan air komposit resin epoksi diperkuat serabut menunjukkan peningkatan. IFSS komposit dengan serabut yang dirawat dengan 2% alkali meningkat sebanyak 10.34%, berbanding komposit dengan serabut yang tidak dirawat. Analisis korelasi menunjukkan tiada korelasi yang ketara antara kekuatan tarik serabut kenaf dan IFSS komposit. Sebaliknya, terdapat hubungan yang signifikan antara geseran permukaan serabut kenaf dan IFSS komposit dengan koefisien korelasi sebanyak 0.905.

Natural Fibre Modification and Its Influence on Fibre-matrix Interfacial Properties in Biocomposite Materials

“…Jute Alkali + silane PLA The interfacial adhesion and shear strength were improved after treatment [66] Kenaf Alkali Epoxy The interfacial shear strength increased after 2 % NaOH treatment compared to untreated composites [91] Wood/rice husk MAPP Polypropylene The treated composites showed improved interfacial adhesion, mechanical properties and thermal stability. It was reported that natural fibre modifications resulted in improved biocomposite properties, owing to better fibrematrix interfacial adhesion [19,48,49].…”

Evaluation on mechanical properties of high‐performance biocomposite bridge deck structure: a review

“…Meanwhile, In the infrared spectrum, the bamboo fibers untreated and treated with 6% and 8% alkaline solutions had the peaks at the wave number of 1718 cm À1 , and the strong absorption peak at 1718 cm À1 indicates the C=O stretching vibration of hemicellulose in bamboo fibers, [98] representing that the hemicellulose still existed in bamboo fibers after 6% and 8% NaOH solutions treatment, while the peak value at 1718 cm À1 disappeared when the concentration of alkaline solutions increased to 10%, 15%, and 25%, it is demonstrated that the hemicellulose in bamboo fibers was almost removed. According to the relevant studies, [99][100][101][102] hemicellulose could be removed at a certain alkali concentration during alkali treatment. In this case, NaOH solutions with a concentration of 10% can basically remove all the hemicellulose in bamboo fibers.…”

Evaluation of mechanical performance and water absorption properties of modified sugarcane bagasse high-density polyethylene plastic bag green composites

“…This could be explained by a possible reason that the washed and treated SCB fiber would promote better fiber-matrix interface adherence and reduced voids in the composites, thereby slowing down the water penetration. 18 It has been reported that alkali treatment aids in cleaning the surface of the bagasse fibers by eliminating hemicellulose and lignin, which consequently reduces fiber diameter (due to fibrillation) which turn in increases of the interface regions, resulting in the decrement in moisture content. 14,30 As the number of hydrophilic hydroxyl groups reduced by NaOH, the hydrophilic nature of modified fiber had changed into a more hydrophobic nature.…”

“…4 Due to the large availability and production of sugarcane in the world, that is approximately 1.7 × 10 3 million tons/year SCB, a lignocellulosic fiber has been receiving researcher's attention in the last decades. 5 SCB possesses adequate tensile strength (170-290 MPa) and Young's modulus (15)(16)(17)(18)(19), which creates its potentiality to be utilized as reinforcement in natural fiber composites. 6 Recently, numerous studies have reported the use of SCB fibers as reinforcing filler for thermoplastic matrices such as polyethylene (PE), polypropylene (PP), and polystyrene; plastics-based composites with superior mechanical properties at different extent were developed.…”