The Synthesis, Characterization And Application Of New Carbon Nanomaterials

The new carbon nanomaterials fullerene C₆₀, C₇₀ and carbon nanotubes were discovered in 1985 and 1991 respectively. Owe to their idiographic structure and unique properties, fullerene and carbon nanotubes have been the most focused researching field and become new nanomaterials science and technology. The techniques of synthesis, purification, extraction, and separation of C₆₀, C₇₀ and carbon nanotubes are presented, the structures, characterization and the applications of C₆₀ and carbon nanotubes are also studied as well in this thesis. There are 7 chapters in this thesis. In chapter 1, the researching progress of fullerene and carbon nanotubes all over the world are reviewed. The characteristic structure, the properties and the application of C₆₀ and carbon nanotubes are reviewed. In chapter 2, the production of C₆₀ C₇₀ using anode arc plasma evaporating graphite rod in helium and argon gas is presented. The techniques of extraction and purification of C₆₀ and C₇₀ using benzene and toluene are given. The separation of C₆₀ and C₇₀ using high performance liquid chromatography is presented. Many parameters such as the kinds of buffer gases, the pressure, the arc current, the stabilization of arc and the purity of graphite rod and graphite block that affecting the C₆₀ and C₇₀ yield ratio are studied carefully in chapter 2, and the prima condition for synthesis C₆₀ and C₇₀ in my designed equipment is presented. The maximal yield ratio of C₆₀ and C₇₀ is 17%. In chapter 3, the production and characterization of ramifications of C₆₀. such as La@C₆₀, C₆₀Br₂₄ and C₆₀(OH)_n are presented. The FTIR spectrum indicate that the product is much more C₆₀Br₂₄ rather than the mixture of brominated fullerites or the bromine doped C₆₀, the spectra of MS, ¹³C NMR and H PLC indicate that the lanthanum atom is trapped in the C₆₀ cage and didn't cause the cage to expand, reduce or deform. It is found by FTIR, FABMS, ¹H NMR and ¹³C NMR spectra that the water-soluble fullerite is multi-hydroxylate fullerite. It is able to exist in water or air for a long time and its solubility in water is more than 100mg/mL at 25℃. In chapter 4, the quasi-straight carbon nanotubes with low structural defects and good quality is synthesized by using anode arc plasma evaporating graphite rod which content iron, nickel and cobalt powder as catalyst of 2 wt %:2 wt %:2 wt % in helium of 6×10⁴ Pa. Many parameters such as the kinds of buffer gases, the pressure, the arc current, the kinds and contents of catalyst, the stabilization of arc and the purity of graphite rod and graphite block that affecting the C₆₀ and C₇₀ yield ratio are studied carefully in chapter 2, and the prima condition for synthesis single-walled carbon nanotubes andtheir bundle with good quality, low impurities and high yield ratio in my designed equipment is presented. The well aligned single-walled carbon nanotubes with low impurity is grown using chemical-vapor-deposition (CVD) method. The product is characterized by TEM, SEM, TAG, XRD and Raman spectra. The anode arc method produced carbon nanotubes attached with many impurities such as amorphous carbon soot, metallic nanoparticles and carbolic metal particles which can be eliminated easily by step by step method using hydrochloric acid, toluene, and the mixture of concentrated nitric acid and saturated solution of potassium permanganate. It is proposed that the magnetic pinching effect of arc current prompt the overlapping of the reactive graphite sheet and form the quasi straight carbon nanotubes with good quality. The general structure and the growth mechanism of fullerene and carbon nanotubes are studied in chapter 5. It is proposed that the stability and their yield ratio of carbon cages correlate with their symmetry. The density and elastic module of single-walled carbon nanotubes and their bundle are also calculated in chapter 5. The carbon nanotubes with heterojunction structure or bifurcate structure are synthesized using anode arc discharge evaporating graphite rod method. In chapter 6, the well aligned carbon nanotubes modified composite SWNT/PMMA with anisotropic mechanical and electrical properties is prepared by stretching method. The electrical conductivity and the mechanical properties of composite rise with the increase of SWNT concentration, composite films showed higher conductivity and higher mechanical draw ratios along the stretched direction than perpendicular to it. The TGA revealed that embedding the SWNTs into the PMMA matrix also improves the thermal stability of the composite. With respect to pure PMMA, the electrical conductivity of 3 wt. % aligned SWNT nanocomposite increased by 9 orders of magnitude, up to 10 3 S/cm, and the maximum draw ratio was higher up to 5000 than pure PMMA of 3500. Two new methods for realign carbon nanotubes in a laminar flow or by using stretching method are proposed. The carbon endohedral magnetic nanoparticles are produced by using the anode arc discharge evaporating graphite rod rich contenting cobalt powder. In chapter 7, the future researching works in the fields of the preparation of organic solar cell and fiducial grid using nano-carbon materials are prospected.