Interphase Development in Polyacrylonitrile/SWNT Nanocomposite and Its Effect on Cyclization and Carbonization for Tuning Carbon Structures

Abstract

In this study, the self-stiffening behavior of polyacrylonitrile (PAN)/carbon nanotube (CNT) nanocomposites is used to develop the interphase structure. Instead of multi-walled carbon nanotubes (MWNTs), single-walled carbon nanotubes (SWNTs) were used, since they provide much more interfacial area with PAN matrix. The effects of SWNT content (0–1.5 wt %) and temperature on the structural development of PAN/SWNT nanocomposites during dynamic straining were compared for processing optimization. Using this unique dynamic straining method, we were able to tune the structures, especially the interphase of PAN/SWNT nanocomposites. The degree of crystallinity of nanocomposite could be improved from 54.3 to 58.5% after dynamic straining for 12 h, and the activation of the PAN glass transition increased from 434 to 1192 kJ/mol. The thermal behaviors of PAN and PAN/SWNT films with various degrees of crystallinity were compared by differential scanning calorimeter and thermal gravimetric analysis. The relationships ...