Nasrin Qistina Nazaruddin, Yusliza Yusuf, Mastura Mohd Taha, Sarita Morakul, Dwi Hadi Sulistyairini
Growing environmental concerns surrounding synthetic fibres have accelerated the search for sustainable alternatives, with recycled polypropylene (rPP) emerging as a cost-effective thermoplastic for Fused Deposition Modelling (FDM) due to its favourable mechanical performance. Nevertheless, FDM-fabricated thermoplastic composites frequently exhibit brittleness, limiting their structural reliability, while the integration of coconut fibre with rPP remains underexplored. This study aims to develop coconut fibre/rPP composite filaments, evaluate their tensile and flexural properties, and examine their potential for sustainable additive manufacturing. Composites were prepared by blending coconut fibre with rPP via hot pressing, followed by filament extrusion and the 3D printing of Honeycomb Sandwich Structures (HCSS). Mechanical characterisation demonstrated that HCSS containing 1 wt% untreated coconut fibre achieved the highest performance, with tensile strength increasing by approximately 5.4% and flexural strength by 10.2% compared with treated coconut fibre. In contrast, fibre contents above 3 wt% resulted in reduced ductility, confirming an inverse relationship between fibre content and the material’s ability to deform under tensile stress. Composites produced with treated fibres showed marginally improved properties; however, untreated fibres at low concentrations delivered competitive performance. These findings establish coconut fibre/rPP composites as a promising and environmentally responsible material system for FDM, with an optimal fibre content of 1 wt% balancing stiffness and ductility for enhanced mechanical reliability in 3D-printed structures. © 2026, National University of Malaysia. All rights reserved.
Fakulti Teknologi dan Kejuruteraan Industri dan Pembuatan, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Melaka, Durian Tunggal, 76100, Malaysia; Design and Sustainability for Additive Manufacturing Research Laboratory (DSAM) Mekanikal, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Melaka, Durian Tunggal, 76100, Malaysia; Intercollaboarative Endodontics and Engineering Research Group, Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University, 254 Phayathai Rd Wangmai Pathumwan, Bangkok, 10330, Thailand; Faculty of Industrial Engineering, Brawijaya University, Jawa Timur, Malang, 65145, Indonesia
