Effect of carbon nanotube on graphitization behavior of CNT/Polyaniline nanocomposite during pyrolysis process

Abstract

Carbon nanotubes (CNTs) have been extensively investigated extensively by researchers in various fields such as chemistry, physics, material science, and electrical engineering due to their exceptional physical, mechanical, electrical, thermal and optical properties. In addition to these properties, small size and high aspect ratio have inspired interest in CNTs as reinforcement in composite. Among various matrices, many researchers have focused on CNT/polymer nanocomposites. The fabrication of CNT containing fibers is of special interest for mechanical and electronic textile applications. Many researchers have attempted to develop CNT/polymer fibers and CNT/C fibers and improve their mechanical properties. However their mechanical properties were much lower than theoretical expectation due to weak interfacial interaction between the CNTs and matrix. Thus, it is critical to study that how CNTs affect the structure of carbon fiber such as degree of graphene plane orientation and degree of graphitization which determine the properties of carbon fibers. In this study, effect of CNT on carbon phase transformation of polyaniline (PANI) during pyrolysis of PANI was investigated by changing process parameters such as volume fraction of CNTs, carbonization temperature, graphitization temperature and by analyzing microstructure change through TG-DSC, FT-IR, EA, XRD, SEM and TEM. CNT/PANI nanocomposite was fabricated by mixing of CNTs with PANI in dimethylformamide (DMF) as solvent. Before mixing process, CNTs were functionalized with acid-treatment to be homogeneously dispersed in DMF. CNT/PANI nanocomposite, obtained by evaporation of DMF was heat treated at $200^\circ C$ in air and at $300^\circ C$ in vacuum to remove remained DMF and stabilize for high temperature process. CNT/PANI nanocomposite was heat treated by spark plasma sintering (SPS) at $1100-1900^\circ C$ for carbonization and graphitization. The morphologies of CNT/PANI and CNT/C nanocomposite were obse...