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 to 320 °C enhances thermal conductivity of MPCFs from 704 to 1078 W·m−1·K−1. • Tensile strength of MPCFs improves from 2.16 to 3.23 GPa with higher spinning temperature. • Higher spinning temperature promotes a transition from fine-and-folded to large-and-flat graphite layer morphology. • Improved molecular orientation due to lower viscosity and reduced die-swell effect at higher temperatures is key to property enhancement.