Key Takeaways & Executive Findings
- •• Ball milling of mesophase pitch concentrates aromatic molecules, leading to uniform foaming and a carbon foam with uniform pore distribution and good properties. • Liquid phase extraction removes light components while retaining large aromatics, resulting in the largest graphitic planes after graphitization. • The carbon foam from liquid phase extraction exhibits the highest degree of graphitization, best compression resistance (2.47 MPa), highest thermal conductivity (64.47 W/(m·K)), and lowest electrical resistance (13.02 μΩ·m). • Semi-quantitative Raman and FTIR analysis combined with microscopic observations enables control over the preparation of mesophase pitch-derived carbon foams.
Abstract
Graphitized carbon foams (GFms) were prepared using mesophase pitch (MP) as a raw material by foaming (450 °C), pre-oxidation (320 °C), carbonization (1 000 °C) and graphitization (2 800 °C). The differences in structure and properties of GFms prepared from different MP precursors pretreated by ball milling or liquid phase extraction were investigated and compared, and semi-quantitative calculations were conducted on the Raman and FTIR spectra of samples at each preparation stage. Semi-quantitative spectroscopic analysis provided detailed information on the structure and chemical composition changes of the MP and GFm derived from it. Combined with microscopic observations, the change from precursor to GFm was analyzed. The results showed that ball milling concentrated the distribution of aromatic molecules in the pitch, which contributed to uniform foaming to give a GFm with a uniform pore distribution and good properties. Liquid phase extraction helped remove light components while retaining large aromatics to form graphitic planes with the largest average size during post-treatment to produce a GFm with the highest degree of graphitization and the fewest open pores, giving the best compression resistance (2.47 MPa), the highest thermal conductivity (64.47 W/(m·K)) and the lowest electrical resistance (13.02 μΩ·m). Characterization combining semi-quantitative spectroscopic analysis with microscopic observations allowed us to control the preparation of the MP-derived GFms.
1. Introduction
Carbon foam, a light carbon material characterized by its sponge-like interconnected porous structure, exhibits remarkable properties including low density, high thermal stability and impact resistance. Furthermore, its customizable thermal and electrical conductivity holds great potential for applications in structural materials, thermal management, electrochemistry and energy storage, catalyst supports, etc.[1–4] Carbon foam can be synthesized from different carbonaceous precursors, polymers such as phenolic resin and polyurethane, various pitches including coal tar pitch, petroleum pitch and naphthalene pitch, as well as biomass materials[5]. Among them, pitch-based carbon foam can form a highly ordered graphite structure after graphitization, exhibiting excellent properties, which has received extensive attention from academia and industry[5].
The unique thermal, electrical and mechanical properties of carbon foams are mainly attributed to the highly aligned or oriented graphitic structure along the pore walls[6]. The pore structure and graphite crystallite size are greatly influenced by the process control, thus investigating the evolution of foam carbon in the whole preparation process is curical. In previous studies, researchers mainly applied electron microscopy and polarized optical microscopy to visually illustrate the evolution of pore structure and graphite orientation[2,7,8], or qualitative Raman and FTIR spectroscopic analysis to indirectly infer changes in fine structure and chemical composition. Nevertheless, it is challenging to provide effective guidance for the controllable synthesis of carbon foam solely through this qualitative characterization. In this study, we conducted further semi-quantitative spectral analysis through peak fitting and calculation of specific aromatic parameters. This approach allowed us to obtain key information about the content and size of polycyclic aromatic hydrocarbons and aliphatic hydrocarbon side chains.
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LIU Yue, CHANG Sheng-kai, SU Zhan-peng, HUANG Zu-jian, QIN Ji, YANG Jian-xiao (2025). Semi-quantitative analysis of the structural evolution of mesophase pitch-based carbon foams by Raman and FTIR spectroscopy. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2024-39-04-06)
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
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Frequently Asked Questions
What are the key steps in preparing graphitized carbon foams from mesophase pitch?
The preparation involves foaming at 450 °C, pre-oxidation at 320 °C, carbonization at 1000 °C, and graphitization at 2800 °C.
How does ball milling affect the properties of mesophase pitch-based carbon foams?
Ball milling concentrates the distribution of aromatic molecules in the pitch, leading to uniform foaming and a carbon foam with uniform pore distribution and good properties.
What are the advantages of liquid phase extraction over ball milling for precursor pretreatment?
Liquid phase extraction removes light components while retaining large aromatics, resulting in larger graphitic planes after graphitization, and producing a carbon foam with the highest degree of graphitization, best compression resistance, highest thermal conductivity, and lowest electrical resistance.
What is the significance of semi-quantitative Raman and FTIR analysis in this study?
Semi-quantitative analysis provides detailed information on structural and chemical composition changes during preparation, enabling control over the final properties of the carbon foams.
What are the optimal properties achieved for the carbon foam from liquid phase extraction?
The carbon foam exhibits a compression resistance of 2.47 MPa, thermal conductivity of 64.47 W/(m·K), and electrical resistance of 13.02 μΩ·m.
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