Enhancing Tribological Performance of 3D‐Printed Novel Hybrid Poly(Lactic) Acid Composites Through Synergistic Reinforcement of Carbon Nanotubes and <i>Delonix regia</i> Pod Ash

ABSTRACT This study presents the fabrication and characterization of poly(lactic acid) (PLA) hybrid composites reinforced with carbon nanotubes (CNTs) and Delonix regia pod ash (DRPA) to improve their mechanical, thermal, and tribological performance. Composites containing 1 wt% CNT and 5 or 10 wt% DRPA were produced using fused deposition modeling (FDM). SEM and XRD analyses confirmed the crystalline tubular morphology of CNT and the irregular, porous structure of DRPA rich in Ca, Si, and Fe. Tensile testing revealed an increase in ultimate tensile strength from 55.6 MPa (PLA) to 72.87 MPa (P3), with a moderate reduction in elongation. TGA and DSC results indicated improved thermal stability and crystallinity with hybrid reinforcement. The Shore D hardness improved by 13.79% for P3, while the contact angle decreased from 73° (P1) to 59° (P4), confirming enhanced surface wettability. The wear rate and coefficient of friction were reduced by 53.2% and 41.8%, respectively, demonstrating synergistic strengthening and lubrication effects of CNT and DRPA. The findings show promising use of CNT and DRPA as co‐reinforcements in biodegradable and wear‐resistant PLA‐based materials.