Carbon Resin Research Articles

An Investigation on the Preparation of Active Carbon-Ceramic Sphere

A procedure for the preparation of active carbon-ceramic sphere was developed. Active carbon-ceramic sphere were prepared by coating a porous ceramic sphere with a phenolic resol resin (carbon precursor). The following procedure was adopted: (a) impregnation of the ceramic substrate with phenolic resol resin; (b) curing; (c) carbonization; (d) activation with KOH etching; (d) washing and drying. Under the optimal impregnation conditions, the material obtained (PRR 70 %) at 30°C, which exhibited a high carbon percentage (~ 5.3 wt.%) with a total pore volume of 0.276 cm3g-1 and a specific surface area of 471 m2g-1 (carbon in the carbon-ceramic sphere) by N2 adsorption, respectively. By means of chemical activation (KC-120), the total pore volume increased to 0.69 cm3g-1 and the specific surface area to 1110 m2g-1 (carbon percentage: 4.73 wt. %), respectively. The activated material shows a uniform carbon distribution, good adsorption properties and a high mechanical strength (24MPa).

Microstructure and Micromechanical Property of C/C-SiC Composites

The C/C-SiC composites are prepared by the reaction molten infiltration process of silicon powders, using porous C/C composites as preform. C/C composite frameworks with various bulk densities are prepared by the chemical vapor infiltration (CVI) combined with the resin impregnation-pyrolysis methods, using needled-carbon fiber felts as preform. Characterization of the microstructure was conducted with a digital microscope (VHX-500) and a polarized light microscopy, respectively. The hardness (H) and the elastic modulus (E) of the composites are measured using a nano indentor. The results show that the indentation behaviors of the pyrolytic carbon and resin carbon are elastic while silicon and silicon carbide show a plastic deformation behavior. The hardness of the resin carbon as well as the pyrolytic carbon is 2.1GPa and 1.3~1.6GPa, respectively. E of SiC varied from 360 to 259GPa and H from 36 to 21GPa. For Si, the value of E and H are 155-170GPa and 11.7GPa, respectively. The relationship between microstructure and mechanical properties of C/C-SiC composites were analyzed.

A Study on the Comparison between Different Matrixes Used for Carbon Fiber Reinforced Composite Core

The comparison between carbon fiber reinforced different matrixes composites was studied in this work. Carbon fiber reinforced phenolic resin composite and carbon fiber reinforced benzoxazine resin composite were made by pultrusion processing. Bending strength test and charpy impact strength test were taken to characterize the toughness of different composites, and scanning electronic micro-scopy(SEM) was applied to evaluate the interfacial properties between carbon fiber and different matrixes. It was shown that compared with carbon fiber reinforced phenolic composite, carbon fiber reinforced benzoxazine composite had better performance in toughness and interfacial property. Bending strength and toughness were mainly depending on the property of matrixes, interfacial property was determined by carbon fiber and matrixes.

Intermediate velocity bullet impact response of laminated glass fiber reinforced hybrid (HEP) resin carbon nano composite

In this study, five different types of six layered GFRP laminates were prepared from three types of resin systems and compared for their intermediate velocity bullet impact response. The first panel was made of epoxy resin, second one is of hybrid resin (a blend of 60% epoxy and 40% polyester) and the remaining three panels were made of hybrid resin with MWCNT in three different proportions by weight (0.1%, 0.5% and 1.0%). The composite and nano-composite panels were characterized experimentally for the important issues in the field of aerospace engineering, like medium velocity bullet impact response and vibration damping characteristics. The MWCNTs were responsible for greater characteristics improvement in the hybrid resin due to their high tendency to absorb the impact shock. The panels without MWCNT turn out to be lesser shock absorption capability. Additionally, 0.1% MWCNT hybrid panel shows exceptional damping response by damping the impacted vibration within 9.5 ms. There is also a 175.51% increase in the damping ratio of the panel. The higher percentage MWCNTs show lesser response towards damping of vibration. This may be due to the lengthy entangled structure of MWCNTs in the resin. It is also observed that the impacted damage is higher in the epoxy system panel than the nano-composite panel.

Preparation and evaluation of magnetic carbonaceous materials for pesticide and metal removal

Magnetic carbonaceous materials were produced by carbonization of a cation exchange resin loaded with ferrous or ferric iron and activation using sieved oyster shell as the activation agent. The magnetic carbonaceous material with the maximum magnetic flux density on every axis (ESS-1) was obtained from the ferric-loaded resin by carbonization at 700 °C, followed by activation with the oyster shell at 900 °C, and magnetization. A separate step of carbonization and activation appears to cause more of a reduction reaction of Fe to form γ-Fe 2O 3. The Fe compound in the magnetic carbonaceous material was identified from the XRD pattern as mainly γ-Fe 2O 3. The magnetic flux density on every axis increased linearly as the amount of the oyster shell increased. Moreover, the adsorption ability of the products was evaluated for pesticides and metal ions. Both ESS-1 and a carbonaceous material obtained from the resin without ferric ion (RC) appear to have the highest adsorption ability for lead. Furthermore, the adsorption ability of ESS-1 might decrease by blockages of the pores with the loaded Fe compounds.

Compressive fracture behavior of 3D needle-punched carbon/carbon composites

Compressive fracture behavior under transverse and longitudinal compressive loading are determined for 3D needle-punched carbon/carbon (C/C) composites with single rough laminar (RL) pyrocarbon matrix or dual matrix of RL pyrocarbon and resin carbon. The results of Weibull statistics analysis indicate that scale parameter σ 0 of transverse and longitudinal compression of the composites with single matrix are 153.41 and 94.26 MPa, and σ 0 of the composites with dual matrix are 205.16 and 105.33 MPa, respectively. The mean compressive strength of both composites is nearly equal to σ 0 under each experimental condition. Failure modes of both composites under transverse and longitudinal compressive loading are shear and extension, respectively. Both composites exhibit quasi-ductile fracture behavior under transverse compression. Many small fragments of fibers and matrix carbon on the fracture surface of the composites are observed for single matrix composites. And the fiber bundle breakage with extensive debonding occurs for dual matrix composites. Under longitudinal loading, the composites with single matrix show quasi-ductile fracture behavior and delamination and splitting of non-woven long carbon fiber cloth layers are observed. The composites with dual matrix exhibit catastrophic failure behavior and crack runs through the composites along compressive loading direction.

Formation and development of micropores in carbon prepared via catalytic carbonization of phenolic resin containing Fe or Ni compounds

The formation and development of micropores in carbon prepared by catalytic carbonization (graphitization) was investigated. Phenolic resin mixed with ferrocene or nickelocene was carbonized at 1000 °C in Ar. A novel mechanical method that was used for mixing phenolic resin and metallic compound favored formation of micropores in the resulting carbon, compared with conventional homogeneous mixing. Decreasing the catalyst content led to increased micropore surface area. At low catalyst content, catalyst particles were finely dispersed. Small (<10 nm) catalyst particles inhibited the development of stacked structures of carbon aromatic layers in the amorphous component (A-component), which in turn produced accessible micropores. Increasing catalyst content facilitated conversion of A-component into turbostratic component (Ts-component) with a partially graphitized structure, which decreased the number of micropores. The formation of Ts-component is related to the formation of mesopores, which progressively replaced micropores as the amount of Ts-component increased.

Effects of heat treatment temperature on oxidation behavior of glass-like carbon derived from acetone-furfural resin

Glass-like carbons (GCs) were prepared by carbonization of acetone-furfural resin in nitrogen atmosphere at 850 °C, followed by heat treatment over a range of 1 200-2 500 °C in inert atmosphere. The effect of heat treatment temperature (HTT) on the oxidation behavior was investigated by dynamic and isothermal thermogravimetric analyses. The structure of GC was examined by X-ray diffractometry (XRD) and the morphologies of GC before and after oxidation were examined by scanning electron microscopy (SEM). It is shown that the GC samples present peculiar oxidation behavior. The anti-oxidation behavior increases with increasing the HTT to 1 600 °C, whereas decreases gradually thereafter. GC sample heat treated at 1 600 °C obtains relatively optimal anti-oxidation properties under this condition. During the oxidation, this material produces grid network matrix surface and numerous nodular residues on the surface, resulting in excellent resistance to the attack of oxygen atoms.

LiFePO4/Polyacene Nanocomposite Synthesized from a Pretreatment of Iron Phosphate: In-situ Polymerization with Phenolic-Formaldehyde Resin

Nanosized LiFePO4 particles coated by uniform thin polyacene layer are synthesized from a pretreatment of FePO4·2H2O. The polyacene layer arises from carbonization of the phenolic-formaldehyde resin which is in situ polymerization to coat the amorphous FePO4·2H2O. The particle sizes of the LiFePO4 /polyacene nanocomposite are in the range of 20−60 nm. This LiFePO4/polyacene nanocomposite delivers discharge capacities of 142, 135, 124, 110 and 80 mAh g−1 at 1 C, 2 C, 5 C, 10 C and 20 C, respectively. The cyclic voltammetry curve and electrochemical impedance spectroscopy reveal low polarization of LiFePO4/polyacene due to the complete coating of polyacene layer on the nanosized LiFePO4 particles. Also the LiFePO4/polyacene nanocomposite shows good electrochemical performances in a wide temperature ranging from −20°C to 60°C.

Phenolic Resin Coated Natural Graphite Oxide as an Anode Material for Lithium Ion Batteries

A core-shell structure of the carbon-coated natural graphite oxide composite was successfully prepared. Natural graphite was initially oxidized using concentrated sulfuric acid and then carbon coated by the carbonization of phenolic resin at high temperature. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman techniques were used to characterize the morphology and structure of the natural graphite materials before and after oxidation and carbon coating by the pyrolysis of the phenolic resin. The results showed that the surface of the natural graphite particles became smoother and the surface defects were effectively modified after oxidation and carbon coating. The electrochemical test results showed that the electrochemical performance of the natural graphite improved significantly by oxidation with sulfuric acid and by carbon coating. When the covering amount of phenolic resin was 9% the modified natural graphite material gave the best electrochemical performance. Its initial discharge capacity was 434.0 mAh·g-1 and it remained 361.6 mAh· g after 40 charge-discharge cycles. The discharge capacity of the untreated natural graphite was only 332.3 mAh·g-1. The modification approach that improved the capacity of the natural graphite effectively is of great significance for the application of natural graphite in lithium ion batteries. [Article] www.whxb.pku.edu.cn 物理化学学报(Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin. 2011, 27 (9), 2129-2134 September Received: May 13, 2011; Revised: July 7, 2011; Published on Web: July 29, 2011. ∗Corresponding author. Email: asyu@fudan.edu.cn; Tel/Fax: +86-21-51630320. The project was supported by the Key Program of Basic Research of the Shanghai Committee of Science and Technology, China (10JC1401500) and Department of Chemistry and Shanghai Key Laboratory of Molecular and Innovative Materials, China (08DZ2270500). 上海市基础研究重点项目(10JC1401500)和上海市分子催化和功能材料重点实验室(08DZ2270500)资助 C Editorial office of Acta Physico-Chimica Sinica 2129 Vol.27 Acta Phys. -Chim. Sin. 2011

Activated Carbons Containing Dispersed Metal Oxide Particles for Removal of Methyl Mercaptan in Air

Activated carbons containing dispersed metal oxide particles were prepared by carbonization of phenol resin containing metal compounds followed by steam activation. Acetylacetonates of Fe, Mn and V, and Cu nitrate were used as the sources of metals. The removal of a small amount of methyl mercaptan (CH3SH) in air with these activated carbons was tested in a flow system. Compared with activated carbons without metal oxides, the carbons exhibited high activity for the removal of CH3SH in air. In particular, activated carbon obtained from Novolac containing 5 wt% Cu showed excellent behavior over a long time.

Study of activated nitrogen-enriched carbon and nitrogen-enriched carbon/carbon aerogel composite as cathode materials for supercapacitors

An activated nitrogen-enriched carbon (ANC) material and a novel activated nitrogen-enriched carbon/carbon aerogel (ANC/ACA) composite were prepared by carbonization and activation of melamine resin and melamine resin/carbon aerogel composite. These were characterized by SEM, XPS, nitrogen adsorption/desorption and electrochemical measurements. Findings indicated than the materials had a highly porous nanometer-sized honeycomb structure and high specific surface area. ANC and ANC/ACA contained 2.22% and 2.12% nitrogen, respectively. The introduction of activated carbon aerogel (ACA) with high conductivity improved the conductivity of ANC. Compared to ACA, greater specific capacitance was obtained for both ANC and ANC/ACA. Asymmetric supercapacitors were assembled with Ni(OH) 2/Co(OH) 2 as anode and our ANC or novel ANC/ACA as cathodes. Electrochemical properties of the supercapacitors with different mass ratios of the two electrodes at different current densities were measured by a galvanostatic charge/discharge technique. When the mass ratio of cathode to anode was 2.2:1 and the current density was 7.5 mA cm −2, the specific capacitance and specific energy of the asymmetric supercapacitor with ANC/ACA as cathode were 110.60 F g −1 and 17.28 Wh kg −1, higher that those of asymmetric supercapacitors with ANC or ACA as cathodes. For ANC/ACA, the attenuation ratio of specific capacitance was only 8.39% after 10,000 cycles. ANC/ACA was found to be a suitable cathode material for use in supercapacitors.

Effect of praseodymium on catalytic graphitization of furan resin carbon

We introduced a new catalyst, rare earth element praseodymium, for the catalytic graphitization of furan resin carbon. The extent of graphitization of the furan resin carbon was examined by X-ray diffraction and Raman spectroscopy. The morphology of furan resin carbon was characterized by scanning electron microscopy. The effects of the praseodymium content and the heat-treatment temperature on the catalytic graphitization of furan resin carbon were also investigated. The results indicated that the praseodymium content and the heat-treatment temperature were two important factors on the catalytic graphitization of furan resin carbon and the significant catalytic graphitization was achieved at 2400 °C and 15 wt.% praseodymium.

Preparation of core-shell silicon/porous carbon powders

Core-shell silicon/porous carbon powders were fabricated by coating silicon powders with phenolic resin,followed by carbonization at 800 ℃ for 2 h.The influence of phenolic resin volume percent,silicon mass percent and aging temperature on the formation of silicon/phenolic resin precursor powders was investigated.The resulting powders were characterized by X-Ray diffraction and scanning electron microscopy The optimum conditions for the formation of silicon/phenolic resin precursor powders are found to be:volume ratio of phenolic resin to alcohol,1;mass ratio of Si to alcohol,2;and aging temperature,at 30-60 ℃.The resin carbon shell of the resulting powders is formed by the pyrolysis of phenolic resin during carbonization treatment and the carbon content in the core-shell silicon/porous carbon increases with the content of phenolic resin in precursor powders.The large amount of gas produced in the pyrolysis process creates pores in the carbon shell.

High porous carbon with Cu/ZnO nanoparticles made by the pyrolysis of carbon material as a catalyst for steam reforming of methanol and dimethyl ether

Cu/ZnO/carbon catalysts for steam reforming reactions were prepared by the technique to obtain much amount of metals highly dispersed on the porous carbon. The preparation method includes the carbonization of an ion exchange resin loaded with metal cations. By containing ZnO in the resin, the agglomeration of Cu particle during the carbonization was suppressed within the carbon matrix due to the difference in the behavior of carbonization and migration between Cu and Zn in the same ion exchange resin, and the Cu particle size was reduced. Thus, the obtained Cu3Zn1 catalyst had more than double the Cu surface area of the catalyst contained only Cu, regardless of lower Cu content. Methanol steam reforming test showed that the catalysts’ activity was positively correlated with Cu surface area. Also in dimethyl ether (DME) steam reforming reactions using the composite catalysts with γ-Al 2O 3, the catalytic activity tracked with the surface area covered by Cu. The optimized Cu/ZnO/carbon catalyst composite showed a high DME conversion of 0.87 even at the low temperature of 300 °C and with GHSV = 2000 h −1, which was due to high dispersion of Cu on the micropore structure of carbon support.

Enhancement of oxygen reduction activity of nanoshell carbons by introducing nitrogen atoms from metal phthalocyanines

Nanoshell carbon is a type of catalytically grown nanocarbon with a hollow, round, shell-like structure, with a diameter in the range of approximately 20–50 nm. It has been shown to possess the electrocatalytic activity for oxygen reduction reaction (ORR) and is also expected to be a non-Pt catalyst for polymer electrolyte fuel cells. This paper reports the synergetic enhancement of the ORR activity of nanoshell carbons caused by the coexistence of nitrogen atoms. The nanoshell carbons were prepared by the carbonization of furan resin in the presence of acetylacetonates (AAs) and of phthalocyanines (Pcs), which contained Fe, Co, and Ni. The Pc-derived nanoshells (MP-T series; M = Co or Fe, T = carbonization temperature) showed higher ORR activities than the AA-derived nanoshells (MA-T series; M = Co or Fe, T = carbonization temperature) when the same metal elements were employed. An XPS study revealed that nitrogen species were introduced to the surface of the nanoshells when Pcs were used as the nanoshell-forming catalysts, and that no metal species remained on the nanoshells. Principally, the ORR activity of the carbons was governed by the presence of the nanoshells and further enhancement could be achieved by the introduction of nitrogen atoms. 0.78 V of OCV and 0.21 W cm −2 of the maximum power density were observed for a fuel cell whose MEA consisted of 3CoP1000 cathode and a commercial Pt/C anode, when it was operated at 80 °C under a pressurized condition of 0.35 MPa.

The effect of MWNTs on the microstructure of resin carbon and thermal conductivity of C/C composites

Multi-walled nanotubes were added into furan resin. Unidirectional carbon/carbon preforms were densified with the nanotube-doped furan resin by impregnation–carbonization cycle. The effects of Multi-walled nanotubes on the microstructure of resin carbon and thermal conductivity of carbon/carbon composites were investigated. The results show that Multi-walled nanotubes can induce the ordered arrangement of planar carbon microlites in resin carbon during high-temperature treatment and enhance the graphitization degree of resin carbon. Small amount of Multi-walled nanotubes in resin carbon can enhance the thermal conductivity of C/C composites evidently, especially the thermal conductivity vertical to the direction of fiber axis, due to the improvement of microstructure of resin carbon. Excess Multi-walled nanotubes in resin are disadvantageous to the enhancement of thermal conductivity instead, because they are difficult to disperse and easy to agglomerate, resulting thermal resistances in carbon matrix.

Catalytically graphitized glass-like carbon examined as anode for lithium-ion cell performing at high charge/discharge rates

Abstract The influence of a long-time heat treatment of hard carbon in the presence of iron catalyst on its structural properties and electrochemical performance is concerned in terms of potential application as anode material for lithium-ion cell. Glass-like carbon spheres obtained by carbonization of phenol resin were catalytically graphitized by heat treatment at temperature 1000 °C in argon atmosphere for 20 h and 100 h. After this process iron was completely removed from the product of reaction. The original carbon was entirely useless as anode for Li-ion cell because of its extremely poor reversible capacity (54 mAh g −1 ). Due to heat treatment composite materials consisting of microcrystalline graphite admixed with turbostratic carbon were produced. Modified carbons were tested as anode materials using gradually increasing current density. Based on electrochemical measurements a mixed intercalation/insertion mechanism for storage of lithium ions was concluded. Discharge capacity of carbon heat treated for 100 h attained value of 276 mAh g −1 and its reversible capacity appeared to be better than that of flaky graphite upon discharging at current density in the range 50–250 mA g −1 .

Monitoring cure in epoxies containing carbon nanotubes with an optical‐fiber Fresnel refractometer

AbstractFresnel refractometry was used to follow the changes in the refractive index during the isothermal curing of a simple difunctional epoxy resin, a commercial formulated multifunctional epoxy blend, and the same two resin systems modified by the addition of multiwalled carbon nanotubes. The refractive index change, monitored via an embedded optical fiber, was correlated with the degree of cure established from isothermal differential scanning calorimetry measurements. A good correlation was established in all cases, indicating the potential of the technique to be used for online cure monitoring in thermosetting resin carbon nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Influence factors of C/C–SiC dual matrix composites prepared by reactive melt infiltration

The effects of the type of carbon matrix, the infiltration temperature and high temperature treatment (HTT) on the infiltration behavior of molten Si and preparation of C/C–SiC dual matrix composites have been investigated. The results showed that: Resin carbon matrix is benificial to the infiltration of molten Si than pyrolysis carbon matrix. 1650 °C is more suitable for the infiltration of molten Si in porous C/C preforms than 1550 °C. The high infiltration depth at 1650 °C is responsible for the high density of C/C–SiC composites. HTT facilitates to the infiltration of molten Si and the formation of more SiC. High density and low open porosity C/C–SiC dual matrix composites can be prepared by optimal reactive molten infiltration method. The flexural strength, elastic modul and impact toughness of C/C–SiC composites are high up to 265.4 MPa, 28.1 GPa and 28.5 kJ/m 2 respectively. Heat treatment at 2300 °C decreases the composites flexural strength, elastic modul and impact toughness, but improve the fracture behavior of C/C–SiC dual matrix composites.