Properties Of Carbon Foams Research Articles

Impact of raw material on thermo‐physical properties of carbon foam

AbstractCarbon foam materials are currently used in several industrial and engineering applications due to their outstanding properties. The properties of carbon foam can be altered through the manufacturing processes applied in specific applications. In this paper, we collected and analyzed four samples manufactured by CFOAM and one sample developed by Ohio University (OU) to understand the behaviour of this material and determine its properties. We utilized advanced techniques to experimentally measure and determine the following properties: pore size and volume, porosity, specific surface area, mass, density, and thermal conductivity. Among the samples, the low‐porosity CFOAM (CF35) and the OU sample exhibited higher specific surface areas and densities compared to the others. However, CF35 demonstrated the highest thermal conductivity, while OU displayed the lowest. As a result, CF35 emerges as the optimal choice for applications requiring high‐rate heat transfer, while the remaining CFOAM samples are well‐suited for lightweight applications. Thus, OU foam proves to be a highly suitable candidate for insulation applications such as building sidewalls.

The Effect of Graphite Loading as Reinforcement on Carbon Foam from Natural Resources

This study is to determine the effect of graphite as reinforcement material on natural resources carbon foam on the mechanical and physical properties. Sucrose is used as carbon precursor and graphite with various concentration from 0 wt% to 0.3 wt% was added into the carbon foam. Carbon foam was prepared by using template method followed by pre curing and carbonization process. Pre curing process was take place at 250°C and carbonization process was carried out at 900°C under inert atmosphere. The morphology, porosity, density and compressive strength were characterised in this experiment. Through Scanning Electron Microscope (SEM), graphite can be seen clearly embedded into the ‘window’ and fill the void space. Porosity of carbon foam decrease when the concentration of graphite increase and the density of carbon foam increase when the concentration of graphite increase. Carbon foam with 0.3 wt% graphite added shows the highest compressive strength (1.84 N/mm2) compared with carbon foam without graphite added (0.95 N/mm2). The properties of carbon foam are significantly influenced by the addition of graphite loading.

Effect of Ti content on microstructure and performance of carbon foam derived from mesophase pitch

A novel carbon foam was prepared from mixtures of mesophase pitch and titanium powder by the traditional process including foaming, carbonization and graphitization. Investigation was carried out to determine the effect on the structure and properties of the carbon foams through the addition of titanium to carbon foams. Results have shown that Ti can promote more perfect and larger crystallites and enhance the conductive/mechanical properties of carbon foams. The high thermal conductivity of 61.89 W/m K was obtained with an addition of 12 wt% Ti at heat treatment temperature of 2573 K. At the same time, the correlations between microstructure and properties are also discussed.

Influence of plasticizers on fire retarding properties of carbon foams of intumescent coatings

Influence of plasticizers on fire retarding properties of carbon foams of intumescent coatings

Preparation and Foaming Mechanism of Pyrocarbon Foams Controlled by Activated Carbon as the Transplantation Core

Carbon foams were prepared with walnut shell liquefaction resin (WLP-PF) as precursor and hexane/activated carbon (H/AC) as foaming core. The effect of the particle size of H/AC and the additive amount of H/AC on the microstructure and properties of carbon foams was investigated. Results showed that when the particle size of H/AC was in the range of 75–150 μm, the bulk density of carbon foams was in the range of 0.115–0.218 g/cm3, the compressive strength (4.79 MPa) reached maximum value, and the Brunauer–Emmett–Teller specific surface area was 721m2/g. Use of foaming core of H/AC made resin with lower viscosity foam. Foaming core of H/AC more uniformly dispersed the blowing agent in WLP-PF resin and improved the microstructure of carbon foams while effectively reducing the micropores in the ligaments and joints. Further, the volume shrinkage rate of carbon foams was reduced by using H/AC for foaming. The foaming mechanism using H/AC was considered to be implantation core foaming accompanied by interfacial nucleation foaming. This led to uniform control of the size and distribution of foam cells.

Enhanced specific surface area by hierarchical porous graphene aerogel/carbon foam for supercapacitor

In this work, graphene aerogel/carbon foam is prepared by in situ inducing graphene aerogels in the pores of carbon foam. This novel hierarchical porous structure possesses a higher specific surface area as the introduction of graphene aerogels in carbon foam increases the proportion of micropores thus making it a superior candidate as electrodes for supercapacitors. The characterization and comparison of various properties of carbon foam and graphene aerogels/carbon foam have been investigated systematically. The result shows that specific surface area is up to 682.8 m2/g compared with initial carbon foam which increased about 55%, and the pore distribution curve shows more pore volume at 0.3 nm for F-CF/GA. It is demonstrated that the introduction of graphene aerogels not only increases the specific surface area, but also improves the conductivity, thus resulting in the reduction of the internal resistance and the improvement of the electrochemical performance. Consequently, graphene aerogel/carbon foam shows an excellent specific capacitance of 193.1 F/g at 1 A/g which is 72% higher than that of carbon foam acted as electrodes for supercapacitors.

Effect of multi walled carbon nanotubes and diamond nanoparticles on the structure and properties of carbon foams

Multi wall carbon nanotubes (MWCNTs) and diamond nanoparticles (DNPs) reinforced carbon foam composites were prepared by the direct pyrolysis of MWCNTs, DNPs and mesophase coal tar pitch mixture. The effect of additive amounts on the microstructure and properties of carbon foams were studied. Significant impacts on the microstructure of carbon foams were observed after the incorporation of additive amounts. Whereas, the additive behavior of MWCNTs and DNPs were further investigated in terms of adsorption, mechanical and thermal properties. The results shows that the nickel (Ni) and cadmium (Cd) metal ions adsorption tendency increases with the increase of MWCNTs and DNPs contents. The maximum adsorption percentage of 84.6 and 86.9% was observed for carbon foam containing 2wt% MWCNT-DNPs loading for Ni and Cd ions respectively. Furthermore, the compressive strength and thermal conductivity of the carbon foams were enhanced with the increase of additives amounts. Maximum improvement of 19.22MPa in the compressive strength and 37.46W/mK at 800°C of thermal conductivity was revealed by carbon foam composite containing 4wt% MWCNT-DNPs additive amounts.

Electrical Properties of Carbon Foam in the Microwave Range

The possibility is shown of a directional change of the dielectric permittivity of carbon foam promising for the use in shielding devices in the microwave frequency range. The frequency dependences of the transmission (T) and reflection (R) coefficients in the Ka-band are experimentally analyzed for the foams with the reticular structure. By the methods of 3D-modeling, the effect of the skeleton conductivity and pore and windows size on the value of electromagnetic shielding provided by such a medium is considered.

The effects of carbon coating onto graphite filler on the structure and properties of carbon foams

The effects of carbon coating onto graphite filler on the structure and properties of carbon foams

Preparation and properties of carbon foam by direct pyrolysis of ally novolak-modified bismaleimide resin

Carbon foam was prepared by direct pyrolysis of ally novolak (AN)-modified bismaleimide (BMI) resin at ambient pressure. Pyrolysis behavior of the AN-modified BMI (AMB) resins was characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). In addition, influences of AN/BMI mass ratio on the structures and properties of the resulting carbon foams were studied. Results show that the AMB resin possesses self-foaming characteristics at high temperatures. The carbon foams have well-developed pore structures with relatively uniform pore sizes; their bulk density, thermal conductivity and compressive strength increase with a decrease in AN/BMI mass ratio. When the AN/BMI mass ratio is 1:1.1, the bulk density, thermal conductivity and compressive strength of the carbon foam arrive at 0.43g/cm3, 1.02W/mK and 6.4MPa, respectively.

Review: tailoring the properties of macroporous carbon foams

Carbon foams are non-toxic, highly porous, light materials which demonstrate a wide range of properties. That fact allows carbon foams to be applied in many areas of life, ranging from electronics industry, through machinery, car and construction industry, to environmental protection. The properties of carbon foams are closely connected with their density, and its value is especially influenced by their internal structure, i.e. mainly size and number of pores, pore wall thickness and structural order of solid matrix. That is why it is possible to design the properties of carbon foams by controlling their growth. The main control factors are selecting the suitable raw material, the process parameters (temperature and pressure) and the suitable production method. Additionally, the properties of carbon foams may be modified by doping them with carbon or mineral fillers. The second method is the enrichment of carbon matrix with heteroatoms, mainly of boron and nitrogen. This paper presents the review of the possibilities of tailoring the structure and properties of carbon foams, based on the current level of knowledge available in the literature.

Double Templating Synthesis and Electrochemical Properties of Carbon Foams

In this paper, we demonstrated the synthesis and electrochemical properties of carbon foams for use as supercapacitor electrode materials. Carbon foams were prepared by double templating method in which emulsion and nanosilica were used as soft template and hard template, respectively. By using Span 80 and Tween 80 as emulsifiers, resorcinol/formaldehyde aqueous solution which contained nanosilica as aqueous phase and 1iquid paraffin as oil phase, an O/W emulsion was obtained. Carbon foams were obtained by emulsion polymerization, carbonization and the subsequent removal of the hard template. The as-prepared carbon foams were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analyzer, and electrochemical workstation. The results indicate that the resultant carbon foams have specific surface area of 160 m2/g, total pore volume of 0.15 cm3/g and possess dual pore size distributions with macropore sizes of 0.5-2.0 μm and the most probable pore size of 4.1 nm. The electrochemical properties of the carbon foams have been investigated by cyclic voltammetry (CV) and galvanostatic charge- discharge with a three-electrode system in electrolyte of 6 mol/L KOH solution. The CV curves of the carbon foams show rectangular-like shape without obvious oxidation-reduction evolution peak, which suggests a typical nonfaradic adsorption/desorption reaction. The carbon foams present linear galvanostatic charge-discharge curve under the current densities of 1.0-5.0 A/g and their specific capacitance values are 60-90 F/g. The good electrochemical performances of carbon foams would provide candidate as electrode materials for supercapacitors.

A study of the properties of mesophase-pitch-based foam/graphitized carbon black composites

Carbon foam was prepared from mixtures of graphitized carbon black particles and Mitsubishi naphthalene based mesophase pitch, followed by foaming, carbonization and graphitization. The influence of graphitized carbon black content on the properties of carbon foams was investigated in detail. The results have shown that less micro-cracks appeared in the carbon foam through the addition of graphitized carbon black to pitch matrix, which prevented the decrease of the strength. The high specific compressive strength of 9.98MPa was achieved with an addition of 10wt.% graphitized carbon black at heat treatment temperature of 2573K. The thermal conductivity decreased gradually with increasing carbon black loading.

Processing and characterization of syntactic carbon foams containing hollow carbon microspheres

The effects of heat-treatment on the properties of carbon foams were studied. The carbon foam was first prepared by adding hollow carbon microspheres to phenolic resin, followed by post-curing, pre-carbonization and carbonization. The mechanisms of failure behaviour and the increase of electrical and thermal conductivities showed that the properties of the foams were influenced by the heat-treatment temperature. Results showed that the introduction of more interval voids during carbonization resulting in a reduction of the mechanical properties. Carbon foams with electrical conductivity of 1.20 S/cm and thermal conductivity of 12.85 W/mK were obtained.

Microstructure and Properties of Carbon Foams Reinforced by CVD PyC

Two carbon foams with different bulk density,marked as CF-1 and CF-2 were prepared from AR mesophase pitch by self-foaming method at 450℃under different foaming pressures,0.1MPa and 3MPa,respectively.Then CF-1 was reinforced by chemical vapor deposition(CVD)PyC for 10h and 70h,getting two carbon foams marked as CF-1-PC1 and CF-1-PC2.The pore structures of four carbon foams were characterized by scanning electron microscope(SEM)and optical microscope(OM),and compressive strength and thermal conductivity were measured in further.The influences of CVD PyC process on carbon foams were investigated.The results show that CVD PyC can widen the ligament of carbon foams and close cracks in pore walls,No obvious interface exists between pitch carbon and PyC. The corresponding bulk density,compressive strength and thermal conductivity of CF-1-PC1 and CF- 1-PC2 are 0.196g·cm~(-3),1.89MPa,0.314W·m~(-1)·K~(-1)and 0.461g·cm~(-3),11.93MPa,1.581W·m~(-1)·K~(-1), respectively.

Electrochemical impedance study of polyaniline electrocoated porous carbon foam

Electropolymerization of aniline on mesophase pitch based carbon foam has been studied in order to evaluate the influence of conductive polymer coating on the properties of carbon foam. The surface morphology of the coating was determined by scanning electron microscopy (SEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical properties of resulting modified carbon foam samples. Polyaniline (PANI) electrocoated-mesophase pitch based carbon foam showed good capacitor behavior in 0.5 M H 2SO 4. Better capacitive behavior is obtained for 100 and 150 mV/s compared to other scan rates, under these faster scan rates thinner films of PANI coatings were combined with more porous structure of carbon foam. Conductivity of the carbon foam was increased from 9.23 to 13.73 S/cm by electrocoating of PANI.

THERMAL CONDUCTIVITY OF GRAPHITIC CARBON FOAMS

Carbon foams are being developed as a new class of thermal management materials. These foams are produced with a wide variety of thermo-mechanical properties; however, very few studies of the properties of carbon foams have been reported in literature. This article reports on an experimental study that was conducted to determine the thermal conductivity of various forms of graphitic carbon foam by using the flash diffusivity and guarded hot plate method. To reduce errors introduced by porous specimen, the test samples were vacuum infiltrated with epoxy. The thermal diffusivity results from the flash diffusivity instrument were used to determine the thermal conductivity of the samples. Some foam samples were determined to have large variations in thermal properties within the sample block. A theoretical and numerical model has been used to examine the effect of the filler epoxy on the experimental results and the influence of pore characteristics on the thermal conductivity of these foams. It was determined that accurate measurement of thermal properties of graphitic foam samples requires careful selection of sample size and measurement technique.

Hierarchical assembly of nanostructured carbon foam

This contribution addresses the unusual structural and electronic properties of carbon foam, a hypothetical new system that may form by a hierarchical self-assembly process from nanostructured graphite. Due its topological relationship to bulk forms of carbon, the postulated foam covers the structural phase space extending from hexagonal diamond to graphite. Ab initio results for the optimized structure indicate that carbon foam should be stable, structurally rigid, and metallic.

Preparation and Properties of Carbon Foam

Preparation and Properties of Carbon Foam