**3. Characterization of carbonaceous mesophase**

Mesophase pitch consists of a large variety of polycyclic aromatic hydrocarbons and maintains the molecular ordering (i.e., optical anisotropy), which is an important precursor for high-performance industrial carbon materials. Characterizing the structures and properties of carbonaceous mesophase plays a significant role in its quality control, process optimization, and applications [5, 17, 18]. Only through effective measurement of the molecular weight distribution and quantitative description of the structural characteristic as well as the multi-scale evaluation of the thermophysical nature will the understanding, controllable preparation, and applications of carbonaceous mesophase be updated. The common instruments used for characterizing carbonaceous mesophase are as follows: Fourier-transform infrared spectrometer (FTIR), elemental analyzer, nuclear magnetic resonance

**105**

**Figure 8.**

**Figure 6.**

**Figure 7.** *1*

scanning calorimetry, etc.

*Preparation, Characterization, and Applications of Carbonaceous Mesophase: A Review*

(NMR), flight mass spectrometer (MS), polarized light microscope, capillary rheometer, X-ray diffractometer, Raman spectrum, thermogravimetric, differential

*MS spectra of (a) naphthalene pitch and (b) its derived mesophase pitch.*

*H-NMR spectra of the soluble fractions from (a) naphthalene pitch and (b) its derived mesophase pitch.*

The carbonaceous mesophase pitch prepared by AlCl3 catalytic thermal polymerization of naphthalene has a relatively high aromaticity (the aromatic index is about 0.70)

*DOI: http://dx.doi.org/10.5772/intechopen.88860*

*FTIR patterns of (a) naphthalene pitch and (b) its derived mesophase pitch.*

*Preparation, Characterization, and Applications of Carbonaceous Mesophase: A Review DOI: http://dx.doi.org/10.5772/intechopen.88860*

**Figure 6.** *FTIR patterns of (a) naphthalene pitch and (b) its derived mesophase pitch.*

**Figure 7.** *1 H-NMR spectra of the soluble fractions from (a) naphthalene pitch and (b) its derived mesophase pitch.*

**Figure 8.** *MS spectra of (a) naphthalene pitch and (b) its derived mesophase pitch.*

(NMR), flight mass spectrometer (MS), polarized light microscope, capillary rheometer, X-ray diffractometer, Raman spectrum, thermogravimetric, differential scanning calorimetry, etc.

The carbonaceous mesophase pitch prepared by AlCl3 catalytic thermal polymerization of naphthalene has a relatively high aromaticity (the aromatic index is about 0.70)

*Liquid Crystals and Display Technology*

**104**

**Figure 5.**

**Figure 4.**

*liquid-crystalline anisotropic spheres.*

**3. Characterization of carbonaceous mesophase**

*suitable reaction condition (scale bar in PLM micrographs is 100 μm).*

Mesophase pitch consists of a large variety of polycyclic aromatic hydrocarbons and maintains the molecular ordering (i.e., optical anisotropy), which is an important precursor for high-performance industrial carbon materials. Characterizing the structures and properties of carbonaceous mesophase plays a significant role in its quality control, process optimization, and applications [5, 17, 18]. Only through effective measurement of the molecular weight distribution and quantitative description of the structural characteristic as well as the multi-scale evaluation of the thermophysical nature will the understanding, controllable preparation, and applications of carbonaceous mesophase be updated. The common instruments used for characterizing carbonaceous mesophase are as follows: Fourier-transform infrared spectrometer (FTIR), elemental analyzer, nuclear magnetic resonance

*(a) Polarized light microscope (PLM) micrograph of the naphthalene-based synthetic pitch and (b) SEM image of broken surface of the pitch-derived coke showing an unsynchronized and inhomogeneous conversion of* 

*Schematic illustration of the formation and development process of bulk liquid-crystalline mesophase under a* 

**Figure 9.** *Typical PLM micrographs of the (a, b) as-received, (c) melted, and (d) melt-stirred naphthalene-based AR mesophase pitch.*

and a regular planar molecular structure constructed by a number of naphthenic structure, as well as a relatively large molecular weight of ~2600 g/mol, consisting of mesogen units (a ladder-shaped molecular structure) formed by ~20 naphthalene molecules through thermally induced aromatic growth [3, 10, 11] according to the analyses of **Figures 6**–**8**. The suitable softening point (260–280°C) and appropriate H/C mol ratio (0.52–0.60), as well as high liquid-crystalline mesophase content (100 vol.%) and ideal fine flow texture as displayed in **Figures 9** and **11**, are the significant characteristics of such carbonaceous mesophase. The analysis results of other characterizations are not shown here (refer to previous work [2, 3, 10, 11, 15, 18]).
