Molecular structure effects of mesophase pitch and isotropic pitch on morphology and properties of carbon nanofibers by electrospinning

Carbon nanofibers (CNFs) with high specific surface area and flexible lap structure are highly desirable for numerous applications such as adsorption films, supercapacitors, heat dissipation elements, and composites. In this work, CNFs were prepared using two major categories of pitches, isotropic pitch (IP) and mesophase pitch (MP), as raw materials to compare their molecular structure effects on the morphology and properties of CNFs. The analysis of scanning electron microscopy results found that some fusions among nanofibers easily formed in IP-derived electrospun nanofibers (IP-SNFs) while an independent and smooth nanofiber morphology were observed in MP-derived electrospun nanofibers (MP-SNFs). Besides, composed of high aromatic molecules content and appropriate aliphatic components, MP-SNFs showed a mitigating exothermic reaction and MP-CNFs exhibited higher specific surface area, conductivity and thermal diffusion coefficient. While with too abundant aliphatic components in IP, there was a violent exothermic reaction of IP-SNFs during the stabilization process, endowing the corresponding IP-CNFs with poor performances. Therefore, thermal behavior of SNFs varied with the molecular structure differences of IP and MP, which had a significant influence on the microstructure and properties of their CNFs. • Fusions were found in IP-CNFs due to the rapid solidification and intense exotherm of IP-SNFs. • The σ and λ of IP-CNFs at 1000 °C (5.83 S cm −1 and 30.34 mm 2 s −1 ) were lower than MP-CNFs' (10.00 S cm −1 and 53.98 mm 2 s −1 ). • Much aliphatic contents in IP led to violent exothermic reactions while MP with more aromatic molecules slowed down them.