Performance of strategically sandwiched continuous sisal fiber core 3D printed PLA composites for engineering applications

The study presents an innovative method to enhance the structural performance of 3D-printed polylactic acid (PLA) composites by strategically incorporating continuous Agave sisalana fibers as a sandwiched core. This architecture aims to overcome existing limitations by enhancing fiber alignment, interfacial bonding, and mechanical performance, while maintaining the lightweight benefits of PLA. Alkaline treatment enhanced fiber/matrix interaction, confirmed via SEM analysis. Compared to neat 3D printed PLA, the treated fiber composite showed notable enhancement of 36.19% in tensile strength and 46.25% in interlaminar shear strength. The treated configuration showed tensile strength of 40.87 MPa and tensile modulus of 2420.88 MPa. While neat 3D printed PLA retained higher flexural strength and modulus, the treated fiber composite excelled in toughness (938.9 kJ/m³) and energy resilience (307 kJ/m³). Dynamic mechanical analysis revealed better thermal stability in the treated fiber composite (Tan δ = 0.53 vs. 1.49 for neat 3D printed PLA). Impact testing showed that untreated fiber layers absorbed more energy, evidenced by the highest puncture force (349.78 N) and maximum deformation. Overall, the study confirms the benefits of a continuous fiber core in optimizing 3D-printed PLA composites and suggests future work on fiber arrangement and volume fraction for enhanced performance.