This study explores the production, characterization, and performance evaluation of carbon fiberreinforced
polymer (CFRP) composite filaments designed for fused deposition modeling (FDM)
applications. The primary objective was to investigate the influence of milled carbon fiber (MCF)
content on the mechanical, moisture absorption, and morphological properties of polypropylene
(PP)-based composites. Composite filaments were produced by blending micro-sized MCFs with PP
granules, followed by a two-step extrusion process to create filaments with varyingMCFcontents
(1–24 wt%). Test specimens were fabricated using 3D printing to evaluate the performance of the
composite materials. The results demonstrated a significant enhancement in mechanical properties
compared to neat PP. The composite with 9.09 achieved optimal performance, exhibiting
increases in tensile and flexural strengths by 74% and 99%, respectively, relative to neat PP. However,
higherMCFcontents (16 and 24 wt%) led to reduced mechanical properties due to insufficient fiber-matrix
adhesion, resulting in fiber pull-out. Moisture absorption studies revealed that the inclusion of
MCFs increased the water uptake of the composites, with higher fiber concentrations correlating to
greater moisture absorption. These findings underline the potential of MCF-reinforced PP composites
for applications requiring improved mechanical performance, such as lightweight structural
components. The study identifies an optimal fiber content of 9.09 wt% for maximizing strength while
minimizing moisture-related trade-offs. Future efforts could focus on enhancing fiber-matrix
bonding to improve performance at higher fiber concentrations.