Enhanced Mechanical and Thermal Properties of MWCNT-Reinforced Hybrid Carbon Fiber/Glass Fiber ABS-PETG Composites Fabricated Via Fused Deposition Modeling

Fused deposition modeling (FDM) enables fabrication of complex composite structures, yet mechanical performance remains limited compared to conventional manufacturing. This study systematically investigates the effect of multi-walled carbon nanotube (MWCNT) loading (1-5 wt%) on mechanical and thermal properties of hybrid carbon fiber/glass fiber reinforced ABS-PETG composites fabricated via dual-extruder FDM. Composites were characterized through tensile testing (ASTM D638), flexural testing (ASTM D790), impact testing (ASTM D256), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), thermal conductivity measurement, and scanning electron microscopy (SEM). Optimal mechanical performance was achieved at 3 wt% MWCNT loading, with tensile strength increasing from 42.5 MPa to 61.4 MPa (+44.5%), Young's modulus from 2.21 GPa to 4.12 GPa (+86.4%), flexural strength from 68.4 MPa to 101.7 MPa (+48.7%), and impact strength from 12.5 kJ/m² to 19.6 kJ/m² (+56.8%). Beyond 3 wt%, agglomeration effects reduced strength properties. Glass transition temperature increased progressively from 106.1°C to 111.2°C at 5 wt% (+5.1°C). Thermal conductivity exhibited continuous enhancement, reaching 0.542 W/m·K at 5 wt% (+188.3%). TGA revealed onset degradation temperature decreased from 398.2°C to 377.3°C at 5 wt%, attributed to catalytic effects of residual CNT metal impurities, while maximum degradation temperature remained relatively stable (433.5-437.1°C). SEM analysis confirmed uniform MWCNT dispersion at 3 wt% and agglomerate formation at higher loadings. The results demonstrate significant potential for aerospace, marine, and structural applications requiring tailored mechanical-thermal property combinations.