UiTM Press Pulau Pinang

HOME: Online Issues

Skip to content

Characteristics of alkaline-modified coconut fibre via microwave-assisted extraction in cementitious composites


Siti Nursyazwani Shahizam Civil Engineering Studies, Universiti Teknologi MARA, Cawangan Pulau Pinang, Permatang Pauh Campus, 13500 Pulau Pinang, Malaysia Mohd Samsudin Abdul Hamid Civil Engineering Studies, Universiti Teknologi MARA, Cawangan Pulau Pinang, Permatang Pauh Campus, 13500 Pulau Pinang, Malaysi Noor Husna Mohammad Nor Chemical Engineering Studies, Universiti Teknologi MARA, Cawangan Pulau Pinang, Permatang Pauh Campus, 13500 Pulau Pinang, Malaysia Endah Kanti Pangestuti Civil Program Studi Teknik Sipil, Universitas Negeri Semarang, Indonesia Arief Kusbiantoro Civil Program Studi Teknik Sipil, Universitas Negeri Semarang, Indonesia Anggy Rio Pratama PT. Pratama Jaya Reka, Kota Semarang, Jawa Tengah, Indonesia
Abstract
Coconut fibre, a lignocellulosic by-product of Cocos nucifera L, is recognised as a sustainable strength-enhancing material in cementitious composites. Untreated fibres, however, exhibit poor interfacial bonding due to surface impurities and limited reactivity. This study examines the effects of NaOH treatment at concentrations of 2, 3.5, and 5 per cent on the microstructural, elemental composition, and functional groups of coconut fibre. SEM analysis revealed progressive morphological refinement as the NaOH concentration increased. SEM observations revealed that untreated coconut fibres possessed rough surfaces covered with non-cellulosic components, which can hinder effective fibre–matrix bonding. Progressive surface modification was observed as NaOH concentration increased, with NaOH-treated fibres exhibiting enhanced surface roughness and porosity, and the removal of surface impurities. EDX confirmed carbon (C) and oxygen (O) as dominant elements. The C-O ratio increased after treatment due to the removal of hydrophobic impurities and greater exposure of cellulose hydroxyl groups. FTIR spectra revealed a broad O-H stretching band around 3400 cm?¹, indicating hydroxyl groups associated with cellulose and the partial removal of hemicellulose, lignin, and surface impurities after treatment. Among the conditions examined, coconut fibre treated with 5% NaOH displayed the most favourable surface characteristics, suggesting a strong potential to improve the fibre-matrix interaction within cementitious composites. These results indicate that alkaline-treated coconut fibre can serve as an effective reinforcement material for the development of sustainable fibre-reinforced concrete.
Keyword: Coconut Fibre, Alkaline modified, Cementitious Composites, Microwave-assisted Extraction, Microstructural Analysis, Functional Group
DOI:10.24191/esteem.v22iMarch.10155
References:
[1] F. R. B. Martinelli, F. R. C. Ribeiro, M. T. Marvila, S. N. Monteiro, F. da C. G. Filho, and A. R. G. de Azevedo, ‘A Review of the Use of Coconut Fiber in Cement Composites’, Mar. 01, 2023, MDPI. Available:https://doi.org/10.3390/polym15051309 [2] J. Zamboni Schiavon and J. J. de Oliveira Andrade, ‘Comparison between alternative chemical treatments on coir fibers for application in cementitious materials’, Journal of Materials Research and Technology, vol. 25, pp. 4634–4649, Jul. 2023. Available:https://doi.org/10.1016/j.jmrt.2023.06.210 [3] T. Eleutério, M. J. Trota, M. G. Meirelles, and H. C. Vasconcelos, ‘A Review of Natural Fibers: Classification, Composition, Extraction, Treatments, and Applications’, Sep. 01, 2025, MDPI. Available:https://doi.org/10.3390/fib13090119 [4] F. Vieira et al., ‘Comparative Study of Pretreatments on Coconut Fiber for Efficient Isolation of Lignocellulosic Fractions’, Sustainability (Switzerland) , vol. 16, no. 11, Jun. 2024. Available:https://doi.org/10.3390/su16114784 [5] I. N. Nasidi, L. H. Ismail, and E. M. Samsudin, ‘Effect of sodium hydroxide (NAOH) treatment on coconut coir fibre and its effectiveness on enhancing sound absorption properties’, Pertanika J. Sci. Technol., vol. 29, no. 1, pp. 693–706, 2021. Available:https://doi.org/10.47836/pjst.29.1.37 [6] J. Ahmad et al., ‘Mechanical and Durability Performance of Coconut Fiber Reinforced Concrete: A State-of-the-Art Review’, May 01, 2022, MDPI. Available:https://doi.org/10.3390/ma15103601 [7] C. H. Lee, A. Khalina, and S. H. Lee, ‘Importance of interfacial adhesion condition on characterization of plant-fiber-reinforced polymer composites: A review’, Feb. 01, 2021, MDPI AG. Available:https://doi.org/ 10.3390/polym13030438. [8] M. Arsyad, ‘Sodium Hydroxide and Potassium Permanganate Treatment on Mechanical Properties of Coconut Fibers’, in IOP Conference Series: Materials Science and Engineering, Institute of Physics Publishing, Oct. 2019. Available:https://doi.org/10.1088/1757-899X/619/1/012011 [9] Q. Hu et al., ‘Microwave technology: a novel approach to the transformation of natural metabolites’, Dec. 01, 2021, BioMed Central Ltd. Available:https://doi.org/10.1186/s13020-021-00500-8 [10] A. Fernandes, L. Cruz-Lopes, B. Esteves, and D. V. Evtuguin, ‘Microwaves and Ultrasound as Emerging Techniques for Lignocellulosic Materials’, Dec. 01, 2023, Multidisciplinary Digital Publishing Institute (MDPI). Available:https://doi.org/10.3390/ma16237351 [11] S. Kumar Yadav, A. Singh, Mt. Student, and A. Professor, ‘A Review on Coconut Fiber Reinforced Concrete’, 2019. [Online]. Available: www.ijsrd.com [12] L. Mishra and G. Basu, ‘Coconut fibre: Its structure, properties, and applications’, in Handbook of Natural Fibres: Second Edition, vol. 1, Elsevier Inc., 2020, pp. 231–255. Available:https://doi.org/ 10.1016/B978-0-12-818398-4.00010-4 [13] J. Ahmad, M. M. Arbili, A. Majdi, F. Althoey, A. Farouk Deifalla, and C. Rahmawati, ‘Performance of concrete reinforced with jute fibers (natural fibers): A review’, 2022, SAGE Publications Ltd. Available:https://doi.org/10.1177/15589250221121871 [14] D. L. Rocha, L. U. D. T. Júnior, M. T. Marvila, E. C. Pereira, D. Souza, and A. R. G. de Azevedo, ‘A Review of the Use of Natural Fibers in Cement Composites: Concepts, Applications and Brazilian History’, May 01, 2022, MDPI. Available:https://doi.org/10.3390/polym14102043 [15] L. Nurhayati et al., ‘Eco-Friendly Nanocellulose from Coconut Fiber: Optimizing Cellulase Enzymes for Sustainable Production’, Asian Journal of Green Chemistry, vol. 9, no. 1, pp. 115–128, Feb. 2025. Available:https://doi.org/10.48309/AJGC.2025.482498.1559 [16] U. A. Sadiq, J. M. Yelwa, and B. O. Michael, ‘Biodegradation and environmental impact of kenaf fiber water filters: Towards sustainable water purification solutions’, International Journal of Chemistry and Materials Research, vol. 13, no. 1, pp. 1–11, Sep. 2025. Available:https://doi.org/ 10.18488/64.v13i1.4409 [17] R. Thandavamoorthy, Y. Devarajan, and S. Thanappan, ‘Analysis of the characterization of NaOH-treated natural cellulose fibre extracted from banyan aerial roots’, Sci. Rep., vol. 13, no. 1, Dec. 2023. Available:https://doi.org/10.1038/s41598-023-39229-9 [18] V. Fiore, T. Scalici, F. Nicoletti, G. Vitale, M. Prestipino, and A. Valenza, ‘A new eco-friendly chemical treatment of natural fibres: Effect of sodium bicarbonate on properties of sisal fibre and its epoxy composites’, Compos. B Eng., vol. 85, pp. 150–160, Feb. 2016. Available:https://doi.org/ 10.1016/j.compositesb.2015.09.028 [19] E. Galicia-Aldama, M. Mayorga, J. C. Arteaga-Arcos, and L. Romero-Salazar, ‘Rheological behaviour of cement paste added with natural fibres’, Constr. Build. Mater., vol. 198, pp. 148–157, Feb. 2019. Available:https://doi.org/10.1016/j.conbuildmat.2018.11.179 [20] H. Zaman, ‘Physico-Mechanical Behaviors of Chemically Treated Natural Fibers Reinforced Hybrid Polypropylene Composites’, Malaysian Journal on Composites Science and Manufacturing, vol. 15, no. 1, pp. 25–40, Nov. 2024. Available:https://doi.org/10.37934/mjcsm.15.1.2540 [21] B. S. Yew, M. Muhamad, S. B. Mohamed, and F. H. Wee, ‘Effect of alkaline treatment on structural characterisation, thermal degradation and water absorption ability of coir fibre polymer composites’, Sains Malays., vol. 48, no. 3, pp. 653–659, Mar. 2019. Available:https://doi.org/10.17576/jsm-2019-4803-19 [22] B. Wang, L. Yan, and B. Kasal, ‘A review of coir fibre and coir fibre reinforced cement-based composite materials (2000–2021)’, Mar. 01, 2022, Elsevier Ltd. Available:https://doi.org/10.1016/j.jclepro.2022.130676 [23] E. Abraham et al., ‘Environmental friendly method for the extraction of coir fibre and isolation of nanofibre’, Carbohydr. Polym., vol. 92, no. 2, pp. 1477–1483, Feb. 2013. Available:https://doi.org/ 10.1016/j.carbpol.2012.10.056 [24] A. I. S. Brígida, V. M. A. Calado, L. R. B. Gonçalves, and M. A. Z. Coelho, ‘Effect of chemical treatments on properties of green coconut fiber’, Carbohydr. Polym., vol. 79, no. 4, pp. 832–838, Mar. 2010. Available:https://doi.org/10.1016/j.carbpol.2009.10.005 [25] M. Mohammed et al., ‘Challenges and advancement in water absorption of natural fiber-reinforced polymer composites’, Jul. 01, 2023, Elsevier Ltd. Available:https//doi.org/10.1016/j.polymertesting.2023.108083 [26] A. Vinod, M. R. Sanjay, S. Siengchin, and S. Fischer, ‘Fully bio-based agro-waste soy stem fiber reinforced bio-epoxy composites for lightweight structural applications: Influence of surface modification techniques’, Constr. Build. Mater., vol. 303, Oct. 2021. Available:https://doi.org/ 10.1016/j.conbuildmat.2021.124509 [27] W. Klunklin, S. Hinmo, P. Thipchai, and P. Rachtanapun, ‘Effect of Bleaching Processes on Physicochemical and Functional Properties of Cellulose and Carboxymethyl Cellulose from Young and Mature Coconut Coir’, Polymers (Basel)., vol. 15, no. 16, Aug. 2023. Available:https://doi.org/ 10.3390/polym15163376 [28] K. M. F. Hasan, P. G. Horváth, M. Bak, and T. Alpár, ‘A state-of-the-art review on coir fiber-reinforced biocomposites’, Mar. 12, 2021, Royal Society of Chemistry. Available:https://doi.org/10.1039/d1ra00231g. [29] F. R. B. Martinelli et al., ‘Influence of drying temperature on coconut-fibers’, Sci. Rep., vol. 14, no. 1, Dec. 2024. Available:https://doi.org/10.1038/s41598-024-56596-z [30] A. Rahayu, F. F. Hanum, N. A. Z. Amrillah, L. W. Lim, and S. Salamah, ‘Cellulose Extraction from Coconut Coir with Alkaline Delignification Process’, Journal of Fibers and Polymer Composites, vol. 1, no. 2, pp. 106–116, Oct. 2022. Available:https://doi.org/10.55043/jfpc.v1i2.51 [31] C. I. Madueke, O. M. Ekechukwu, and F. O. Kolawole, ‘A Review on Coir Fibre, Coir Fibre Reinforced Polymer Composites and Their Current Applications’, 2024, Tech Science Press. Available:https:doi.org/10.32604/jrm.2024.055207 [32] C. I. Madueke, F. Kolawole, and J. Tile, ‘Retraction: Property evaluations of coir fibres for use as reinforcement in composites’, Feb. 01, 2021, Springer Nature. Available:https://doi.org/10.1007/s42452-021-04283-3. [33] Y. R. Ng, S. N. A. M. Shahid, and N. I. A. A. Nordin, ‘The effect of alkali treatment on tensile properties of coir/polypropylene bio composite’, in IOP Conference Series: Materials Science and Engineering, Institute of Physics Publishing, Jun. 2018. Available:https://doi.org/10.1088/1757-899X/368/1/012048 [34] S. Ru, C. Zhao, S. Yang, and D. Liang, ‘Effect of Coir Fiber Surface Treatment on Interfacial Properties of Reinforced Epoxy Resin Composites’, Polymers (Basel)., vol. 14, no. 17, Sep. 2022. Available:https://doi.org/10.3390/polym14173488. [35] L. Yan, N. Chouw, L. Huang, and B. Kasal, ‘Effect of alkali treatment on microstructure and mechanical properties of coir fibres, coir fibre reinforced-polymer composites and reinforced-cementitious composites’, Constr. Build. Mater., vol. 112, pp. 168–182, Jun. 2016. Available:https://doi.org/10.1016/j.conbuildmat.2016.02.182 [36] D. Dange and R. Gnanamoorthy, ‘Effect of alkaline treatment of coir fibre on the interfacial adhesion in coir fibre-reinforced polylactic acid bio-composite’, Mater. Today Proc., 2023. Available:https://doi.org/10.1016/j.matpr.2023.03.730 [37] I. Elfaleh et al., ‘A comprehensive review of natural fibers and their composites: An eco-friendly alternative to conventional materials’, Sep. 01, 2023, Elsevier B.V. Available:https://doi.org/ 10.1016/j.rineng.2023.101271 [38] A. Kumar and K. S. Prasad, ‘Role of nano-selenium in health and environment’, Jan. 10, 2021, Elsevier B.V. Available:https:doi.org/10.1016/j.jbiotec.2020.11.004.