Effect of NaOH Concentration on the Structural, Morphological, and Tensile Properties of Pineapple Stem Fibers

Authors

• Ahmad Norca Kurnia Zen, Master Program of Mechanical Engineering, Faculty of Engineering, State University of Malang, IndonesiaFollow
• Heru Suryanto, Master Program of Mechanical Engineering, Faculty of Engineering, State University of Malang, IndonesiaFollow
• Aminnudin Aminnudin, Master Program of Mechanical Engineering, Faculty of Engineering, State University of Malang, IndonesiaFollow
• Fajar Nusantara, Master Program of Mechanical Engineering, Faculty of Engineering, State University of Malang, IndonesiaFollow
• Joseph Selvi Binoj, Department of Mechanical Engineering, College of Engineering, Alasala Colleges, Dammam, Eastern Province, Kingdom of Saudi ArabiaFollow

Abstract

Natural fiber reinforced composites are increasingly being developed due to their environmentally friendly nature, low production costs, and safety for human health. However, the presence of lignin and hemicellulose reduces adhesion properties between fiber and composite matrix. Alkalization treatment is an effective way to remove lignin and hemicellulose attached to cellulose. This study aims to determine the optimum concentration of NaOH used during alkalization process of pineapple stem fiber. The methods included the retting process of fibers from pineapple stems. The obtained fibers were soaked in variations of 2%, 4%, 6%, and 8% NaOH for 4 hours,  then dried and characterized using a tensile tester, X-ray diffraction, Fourier transform infrared, and scanning electron microscopy. The results showed changes in  morphology of fiber surface, which was initially covered by hemicellulose and lignin, were removed due to the alkalization process, but damage on fiber occurred at high NaOH variations. XRD results show diffraction at 2θ = 22^o with increased crystallinity in the 2% and 4% NaOH variants, which then decreases in the 6% and 8% variants. The FTIR spectrum shows the loss of functional groups of hemicellulose and lignin from the fiber after the alkalization process. Tensile tests show that a concentration of 4% NaOH produces pineapple stem fibers with the highest increase in tensile strength.

Publisher

State University of Malang (UM)

First Page

118

Last Page

128

Recommended Citation

Zen, A. K., Suryanto, H., Aminnudin, A., Nusantara, F., & Binoj, J. S. (2026). Effect of NaOH Concentration on the Structural, Morphological, and Tensile Properties of Pineapple Stem Fibers. Journal of Mechanical Engineering Science and Technology (JMEST), 10(1), 118-128.
Available at: https://citeus.um.ac.id/jmest/vol10/iss1/9