| 초록 |
Single-walled carbon nanotubes (SWNTs) are known to have high mechanical strength, chemical inertness, and excellent thermal and electrical conductivities. To have manufacturing efficiency and to transfer their outstanding properties as nanoscale additives, there must be a few fundamental issues needed to be resolved first. They are related to (i) cost-effective synthesis with high purity (ii) facile purification method without damaging SWNT (iii) the effective aspect ratio, which is largely determined by the state of dispersion and (iv) interfacial adhesion between additives and matrix. Thus, developing an efficient purification and chemical modification methods without or with little damages to the surface of CNT is very important for the development of ultimate nanocomposites. In this regards, we have attempted to purify and functionalize SWNT in a mild and non-destructive medium in polyphosphoric acid (PPA) with or without additional phosphorous pentoxide at various temperatures 130, 160, and 190 ºC. Its moderately acidic nature promotes de-bundling of SWNT to decompose presenting defective impurities and to promote homogeneous dispersion without or little damaging them, and its viscous character helps to impede SWNT reaggregation after their dispersion. In this paper, we describe our continuing effort on the purification and functionalization of SWNT to effect its homogeneous dispersion in various media. The purification and functionalization progresses of SWNT was traced by a Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), tunneling electron microscopy (TEM), elemental analysis (EA), thermogravimetric analysis (TGA). |
