Carbon materials are indispensable core materials used in many industries, and its size is reported to exceed about 400 billion won, showing an increase of more than 5% every year. There has been a particular increase in the demand for carbon materials in relation to the recent expansion of renewable energy industries and the increased production of energy-saving products. The domestic carbon material market accounts for more than 50% of all electric furnace operations and carbon and graphite moldings. In addition to their use in motor brushes, mechanical seals, and electrical discharge machining (EDM) electrodes, carbon materials have been extensively used in heating element and ceramic products because of the wide use of polycrystalline silicon in semiconductors and solar cells.
The raw materials used for manufacturing carbon materials are remnants of the oil refining industry and coal tar and by-products of the steel industry. Although these by-products are inexpensive, carbon materials are assumed to be manufactured very cheaply. substantially shall manage to ensure a stable physical properties agent by thoroughly control the operating conditions of the type of starting material, the blending ratio and the facility to inject in order to obtain a raw material capable of producing a carbon material. And the case of coal tar is used to allow a carbon material for preparing the raw material solids removal, such as a coal powder is essential, in the case of refinery residues, the use is possible as a carbon material for producing a raw material as a non-through the hydrodesulfurization treatment, oil removing and dewax process. oil and petroleum pitches made during the petrochemical processes are important materials used in electrodes, such as lithium ion electrode anode material, binders, carbon composite bases, and raw materials for the cutting-edge new materials (such as those in the electronics and energy industries).
In this study, the binder pitches were manufactured using petroleum residue oil and applied to various carbon composite materials. The first stage of the experiments involved the preparation of petroleum-based mesophase pitches from pyrolyzed fuel oil (PFO) through a heat treatment. The mesophase was fabricated by conducting an additional heat treatment with the PFO-based raw pitches. During the formation of the mesophase, small spherical particles were generated when the reaction temperature was increased at temperatures under 400℃; during heat treatment at temperatures above 400℃, the small spherical mesophase structures coalesced to form bulk mesophase structures. Furthermore, with an increase in the temperature and time employed, the softening point, carbon/hydrogen (C/H) ratio, and amount of quinoline-insoluble (QI) material required for the binder pitches increased significantly, which thus confirmed an increase in the mesophase content.
In the second stage, the effects of one-step preparation on the mechanical properties of carbon/carbon (C/C) composites impregnated with mesophase binder pitches and phenolic resins were investigated. The C/C composites containing four types of 20 wt% mesophase binder pitches were found to have different softening points (SP) and QI contents. After investigating the mesophase formed by using different heat treatment temperatures and times, it was determined that the optimal density and mechanical properties of C/C composites were achieved using mesophase binder pitches with a SP of 170℃. There were no further improvements in the density of the C/C composites when an SP of 200℃ was used, because the binder pitches were not properly impregnated into the composites due to the high viscosity and QI of the binder pitches. Furthermore, the C/C composites fabricated with 20 wt% pitch 2 exhibited the highest mechanical properties.
In the third stage, conductive carbon fillers, such as petroleum coke, carbon black, and graphite, with phenolic resins were used to improve the surface heating elements by impregnating the pitch-based carbon paper (CP). The influence of the conductive carbon fillers on the physicochemical properties of the CP was investigated through electrical resistance measurements and thermal analysis. The results showed a linear decease in the surface resistance and interfacial contact resistivity of the CP when it was impregnated with carbon fillers containing phenolic resins. Moreover, an increase in the carbon filler content improved the electrical and thermal conductivity of the CP. In addition, the heating characteristics of the surface heating element were examined by using applied voltages ranging from 1 V to 5 V. By using the applied voltage, the surface heating element was confirmed to exhibit the maximum heating characteristic of approximately 202.2℃ (at 5 V). These results can be attributed to the formation of electrical and thermal networks by the filling of micropores between the carbon fibers, which caused an improvement in the electrical and thermal properties of the CP.
In the fourth stage of the experiment, ordered and disordered mesoporous carbons were prepared using an organic-organic self-assembly method, and a mixture of phenolic resins and petroleum-based-mesophase binder pitches were used as the starting material. In addition, amphiphilic tricopolymers F127 was employed as a soft-template, hydrochloric acid (HCL) as a catalyst, and distilled water as a solvent. Mesoporous carbons were synthesized at a low temperature and also carbonized at a low temperature (600℃). At this time, the porous carbon body having a mesophase pitches content of about 10 wt% was confirmed by the porous carbon body structure through X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and Transmission electron microscopy (TEM), and the porous carbon bodies having a pore size of about 5.0 nm of the hexagonal pore structure were regularly arranged. I could confirm that. In addition, the porous carbon body prepared through various synthesis methods showed a regular or amorphous carbon structure, and the specific surface area and pore volume of the porous carbon body showed values of up to 756 m2/s and 0.63 cm3/g, respectively.