MORPHOLOGICAL, CHEMICAL, AND THERMO-MECHANICAL PROPERTIES OF TREATED UNTWISTED KENAF YARN

Syukrina Harun; Nor Dalila Nor Affandi; Wan Mohd Nazri  Wan Abd Rahman; Jamaluddin Mahmud; Muhammad Hussain  Ismail; Mohd Rozi  Ahmad; Mohd Iqbal  Misnon; Noor Najmi  Bonnia

Syukrina Harun Textile Research Group, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Nor Dalila Nor Affandi Textile Research Group, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Wan Mohd Nazri Wan Abd Rahman Faculty of Applied Sciences, Universiti Teknologi MARA Cawangan Pahang, 26400 Bandar Tun Abdul Razak Jengka, Pahang, Malaysia
Jamaluddin Mahmud Faculty of Mechanical Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Muhammad Hussain Ismail Faculty of Mechanical Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Mohd Rozi Ahmad Textile Research Group, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Mohd Iqbal Misnon Textile Research Group, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
Noor Najmi Bonnia Material Science and Technology, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia

Keywords: Kenaf fibre, untwisted kenaf yarn, FTIR, TGA, tensile properties

Abstract

Kenaf (Hibiscus cannabinus L.) is widely recognised for its high cellulose content, strength-to-weight ratio, and abundant availability. However, studies on the fundamental effects of water and thermal treatment on untwisted kenaf yarns remain limited. Hence, this study aims to investigate the behaviour of untwisted kenaf yarns under moisture and heat exposure by analysing their morphological, chemical, and thermo-mechanical properties. The control kenaf fibres and untwisted kenaf yarns subjected to water and heat treatments were characterised using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and tensile testing. SEM observations showed that water treated kenaf yarn exhibited more aligned, compact, and smoother fibre bundles than the loosely packed control kenaf fibres. The fibre diameter of the treated kenaf yarn was 12.46 % smaller than that of the control kenaf fibres. FTIR analysis showed an increase in the O-H stretching intensity (3330–3400 cm⁻¹) and a prominent C=O peak at 1730 cm⁻¹, indicating partial modification of hemicellulose and a rearrangement of hydrogen bonds within the treated kenaf yarn fibres. TGA results showed two degradation stages at around 240 °C and 311 °C, with the treated yarn exhibiting a higher total weight loss than the control fibres. Tensile testing revealed that the treated kenaf yarn exhibited a higher tensile stress of 101.73 ± 51.46 mN/Tex compared to the control kenaf fibres at 98.66 ± 22.35 mN/Tex, accompanied by a slight reduction in tensile strain from 1.028% to 1.025 %. Overall, the combined water and heat treatment improved fibre alignment, compactness, and tensile stress while slightly reducing ductility. These enhancements demonstrate the potential of this eco-friendly processing method to produce untwisted kenaf yarns.