Improving the mechanical properties and thermal conductivity of mesophase-pitch-based carbon fibers by controlling the temperature in industrial spinning equipment

• Increasing spinning temperature from 309°C to 320°C in industrial equipment enhances both thermal conductivity (from 704 to 1078 W·m−1·K−1) and tensile strength (from 2.16 to 3.23 GPa) of mesophase-pitch-based carbon fibers. • Higher spinning temperature induces a morphological transition in graphite layers from fine-and-folded to large-and-flat, indicating improved molecular orientation. • The improved properties are attributed to reduced viscosity and weaker die-swell effect at spinneret outlets, leading to better alignment of mesophase pitch molecules. • This study provides a practical approach for industrial production of high-performance carbon fibers with superior thermal and mechanical properties.