Presence Of Carbon Nanofibers Research Articles

The Effect of Carbon Nanofibers on the Hydrocracking of Vacuum Residue in the Presence of Formic Acid

This study was devoted to the processing of vacuum residue to produce lighter oil fractions, such as gasoline and diesel fuel. The hydrocracking and catalytic hydrocracking of vacuum residue in the presence of formic acid (FA) were performed in the temperature range of 250–550 °C. Carbon nanofibers (CNFs) were used as catalytic additives. In contrast to conventional hydrocracking, an important stage in the catalytic hydrocracking of vacuum residue is the decomposition of formic acid. Experimental studies on the effect of CNFs on the decomposition of FA demonstrated that CNFs pre-treated in a NaOH solution (CNF (NaOH)s) had the highest activity and selectivity for the production of H2 and CO2. The maximum yield of liquid products in the catalytic hydrocracking process, equal to 34 wt.%, was observed at 300 °C in the presence of CNF (NaOH)s. The characterization of the fractional compositions of the liquid products showed that the ratios of the fractions changed with an increase in the reaction temperature. The maximum concentrations of the light fractions (gasoline and diesel) in the liquid products of the catalytic hydrocracking of vacuum residue were observed at 300–350 °C in the presence of CNF (NaOH)s.

Microfluidic Platform Integrated with Carbon Nanofibers-Decorated Gold Nanoporous Sensing Device for Serum PSA Quantification.

Prostate cancer is a disease with a high incidence and mortality rate in men worldwide. Serum prostate-specific antigens (PSA) are the main circulating biomarker for this disease in clinical practices. In this work, we present a portable and reusable microfluidic device for PSA quantification. This device comprises a polymethyl methacrylate microfluidic platform coupled with electrochemical detection. The platinum working microelectrode was positioned in the outflow region of the microchannel and was modified with carbon nanofibers (CNF)-decorated gold nanoporous (GNP) structures by the dynamic hydrogen bubble template method, through the simultaneous electrodeposition of metal precursors in the presence of CNF. CNF/GNP structures exhibit attractive properties, such as a large surface to volume ratio, which increases the antibody's immobilization capacity and the electroactive area. CNFs/GNP structures were characterized by scanning electron microscopy, energy dispersive spectrometry, and cyclic voltammetry. Anti-PSA antibodies and HRP were employed for the immune-electrochemical reaction. The detection limit for the device was 5 pg mL-1, with a linear range from 0.01 to 50 ng mL-1. The coefficients of variation within and between assays were lower than 4.40%, and 6.15%, respectively. Additionally, its clinical performance was tested in serum from 30 prostate cancer patients. This novel device was a sensitive, selective, portable, and reusable tool for the serological diagnosis and monitoring of prostate cancer.

Hierarchical Pt/NiCo2O4 nanosheets decorated carbon nanofibers for room-temperature catalytic formaldehyde oxidation

Room-temperature catalytic formaldehyde (HCHO) oxidation is regarded as the most promising way for constant and oxidative removal of indoor HCHO. Herein, carbon nanofibers (CNF) with three-dimensional (3D) interconnection network structure decorated with Pt/NiCo2O4 alloy nanosheets (Pt/NiCo2O4/CNF) were fabricated in-situ to catalyze the oxidation of HCHO at ambient temperature. The presence of CNF helps to inhibit the aggregation of NiCo2O4 nanosheets, expose more active sites and form a hierarchically porous structure, which is conducive to the dispersion of platinum nanoparticles (NPs) and the diffusion of reactants. Besides, oxygen vacancies from Pt-loading process ensure abundant active oxygen species, which are beneficial to HCHO oxidation. Moreover, CNF with microporous structure can strongly adsorb HCHO, rapidly reduce the concentration of HCHO in air and increase its concentration near Pt/NiCo2O4, thus accelerating the formaldehyde oxidation reaction. At Pt content as low as 0.5 wt%, Pt/NiCo2O4/CNF exhibits superior HCHO oxidation activity, and conversion of 92.4% can be achieved within 60 min due to the combination of adsorption and oxidation. This work may shed light on fabricating CNF-based 3D catalysts for the practical application of indoor HCHO elimination.

Surface modification of polyether ether ketone implant with a novel nanocomposite coating containing poly (vinylidene fluoride) toward improving piezoelectric and bioactivity performance

Polyether ether ketone (PEEK) is an appropriate biomaterial for orthopedic implant applications due to its superior mechanical properties, chemical resistance, nontoxicity, and Magnetic resonance imaging (MRI) compatibility. Unfortunately, the inherent bio-inertness of PEEK restricted its application and required some modification to provide better bioactivity. Besides it, the generated electrical signals in the bone due to its piezoelectricity features have a vital role in regulating bone repair and regeneration. We aimed to modify the surface of PEEK with a dual-functionality nanocomposite that provides surface bioactivity and simulates the piezoelectricity of bone. So, we introduced a novel piezoelectric-bioactive nanocomposite of dispersed poly (vinylidene fluoride) (PVDF) in a sulfonated PEEK (SPEEK) matrix containing Nanohydroxyapatite (nHA) and Carbon nanofiber (CNF) fillers for coating on PEEK substrate to improve its biological activity and simulate the electrical microenvironment for bone tissue. Furthermore, sulfonation of the PEEK surface was conducted as an intermediate layer to prepare better adhesion between the coating nanocomposite and the PEEK sublayer. Surface and cross-section morphology, apatite formation, and cell attachment were investigated on the different treated PEEK surfaces using field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDX). Also, piezoelectric performance, electrical conductivity, contact angle, and mechanical properties were examined on the prepared samples. Moreover, cell viability and cell morphology were investigated for biological evaluation with human osteoblast-like MG-63 cells. Collectively, the hydrophilicity of modified PEEK (mPEEK) coated with nanocomposite was improved due to the synergistic effects of SPEEK functional groups and nHA. Also, comprehensive investigation on the mPEEK treated with nanocomposite indicated a noticeably better bone-like apatite formation, cell proliferation, and cell attachments in the presence of nHA. The transfer of induced piezoelectric charges from dispersed PVDF in the matrix to the surface of nanocomposite containing 2 wt% of CNF increased output voltage to 1893 mV. On the other hand, the presence of CNF in nanocomposites enhanced tensile strength and Young's modulus by 92% and 117%, respectively.

Nanofiber Concrete: Multi-Level Reinforcement

Concrete is the most commonly used building material worldwide. One of its main disadvantages is the fragility of fracture and low crack resistance. The use of dispersed reinforcement of concrete composites is a promising direction in solving this type of problem. Dispersed fibers, evenly distributed over the entire volume of the material, create a spatial frame and contribute to the inhibition of developing cracks under the action of destructive forces. In order to increase the fracture toughness of concrete, dispersed fiber reinforcement is increasingly used in practice. The beginning of crack nucleation occurs at the nanoscale in the cement matrix. Thus, the use of nano-reinforcement with dispersed nanofibers can have a positive effect on the crack resistance of the cement composite. It is proposed to consider carbon nanotubes as such nanofibers. The presence of carbon nanofibers changes the microstructure and nanostructure of cement modified with carbon nanotubes. The result of the processes occurring in capillaries and cracks are deformations in the intergranular matrix, the free flow of which is prevented by rigid clinker grains and nanocarbon tubes, which creates a certain stress intensity at the tips of the separation cracks. The working hypothesis is confirmed that the required fracture toughness of structural concrete is provided by multi-level reinforcement: at the level of the crystalline aggregate of cement stone – carbon nanotubes, and at the level of fine-grained concrete – various macro-sized fibers (steel, polymer). Reinforcement of a crystalline joint with carbon nanotubes leads to an increase in the fracture toughness of the matrix (cement stone) by 20 %, compressive strength by 12 %, and tensile strength in bending by 20 %. When reinforcing at the level of fine-grained concrete, we obtain a composite – nanofibre-reinforced concrete with fracture toughness.

High-Performance Properties of an Aerospace Epoxy Resin Loaded with Carbon Nanofibers and Glycidyl Polyhedral Oligomeric Silsesquioxane

This paper proposes a new multifunctional flame retardant carbon nanofiber/glycidyl polyhedral oligomeric silsesquioxane (GPOSS) epoxy formulation specially designed for lightweight composite materials capable of fulfilling the ever-changing demands of the future aerospace industry. The multifunctional resin was designed to satisfy structural and functional requirements. In particular, this paper explores the advantages deriving from the combined use of GPOSS and CNFs (short carbon nanofibers) to obtain multifunctional resins. The multifunctional material was prepared by incorporating in the epoxy matrix heat-treated carbon nanofibers (CNFs) at the percentage of 0.5 wt% and GPOSS compound at 5 wt% in order to increase the mechanical performance, electrical conductivity, thermal stability and flame resistance property of the resulting nanocomposite. Dynamic mechanical analysis (DMA) shows that the values of the Storage Modulus (S.M.) of the resin alone and the resin containing solubilized GPOSS nanocages are almost similar in a wide range of temperatures (from 30 °C to 165 °C). The presence of CNFs, in the percentage of 0.5 wt%, determines an enhancement in the S.M. of 700 MPa from −30 °C to 180 °C with respect to the resin matrix and the resin/GPOSS systems. Hence, a value higher than 2700 MPa is detected from 30 °C to 110 °C. Furthermore, the electrical conductivity of the sample containing both GPOSS and CNFs reaches the value of 1.35 × 10−1 S/m, which is a very satisfying value to contrast the electrical insulating property of the epoxy systems. For the first time, TUNA tests have been performed on the formulation where the advantages of GPOSS and CNFs are combined. TUNA investigation highlights an electrically conductive network well distributed in the sample. The ignition time of the multifunctional nanocomposite is higher than that of the sample containing GPOSS alone of about 35%.

Application of a Screen-Printed Sensor Modified with Carbon Nanofibers for the Voltammetric Analysis of an Anticancer Disubstituted Fused Triazinone.

In this paper, we propose the first analytical procedure—using a screen-printed carbon electrode modified with carbon nanofibers (SPCE/CNFs)—for the detection and quantitative determination of an electroactive disubstituted fused triazinone, namely 4-Cl-PIMT, which is a promising anticancer drug candidate. The electrochemical performances of the sensor were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square-wave adsorptive stripping voltammetry (SWAdSV). The presence of carbon nanofibers on the sensor surface caused a decrease in charge-transfer resistance and an increase in the active surface compared to the bare SPCE. Under the optimised experimental conditions, the proposed voltammetric procedure possesses a good linear response for the determination of 4-Cl-PIMT in the two linear ranges of 0.5–10 nM and 10–100 nM. The low limits of detection and quantification were calculated at 0.099 and 0.33 nM, respectively. In addition, the sensor displays high reproducibility and repeatability, as well as good selectivity. The selectivity was improved through the use of a flow system and a short accumulation time. The SWAdSV procedure with SPCE/CNFs was applied to determine 4-Cl-PIMT in human serum samples. The SWAdSV results were compared to those obtained by the ultra-high-performance liquid chromatography coupled with electrospray ionization/single-quadrupole mass spectrometry (UHPLC-ESI-MS) method.

Effect of Carbon Nanofibers (CNF) on The Crystallization Kinetics of Polyphenylene Sulfide (PPS)

The presence of a reinforcement in polymeric materials can cause alterations in their physical properties, and increase the crystallization rate of their polymeric matrix. Therefore, this research work was oriented toward the incorporation of different percentages of carbon nanofibers (0.6-1-3 and 5%) in a PPS thermoplastic matrix, with the purpose to establish and understand each one of the variables that control crystallization kinetics. The results showed a gradual decrease in crystallization times for contents of up to 5% of CNF, where carbon nanofibers act as nucleation sites, accelerating the crystallization process. According to the values obtained in the Avrami exponent, these fell within a range that oscillates from 2.5 to 3 for pure PPS and PPS/1%CNF which indicates that the presence of carbon nanofibers does not have an effect on the nucleation mechanism of polyphenylene sulphide crystalline phase, thus suggesting crystallization with heterogeneous nucleation and two-dimensional growth with circular geometry

The Effect of Carbon Nanofiber on the Dynamic and Mechanical Properties of Epoxy/Glass Microballoon Syntactic Foam

The aim of this study was to research the effect of carbon nanofiber (CNF), the microballoon (MB) volume fraction and its density on both the vibration properties and impact behavior of carbon nanofiber – reinforced syntactic foam. Twelve different types of syntactic foam were produced with two different CNF contents, two different MB densities and two different MB volume fractions. Neat epoxy, syntactic foams with and without carbon nanofiber were manufactured for characterization by comparing each other in terms of mechanical and dynamic properties. With the free vibration tests, natural frequencies and damping ratios were investigated. Besides vibrations tests, low-velocity impact and tensile tests were conducted on the syntactic foams. Analyses of the results were performed on the effect of the volume fraction of additives and MB density on the vibration, impact and tensile behavior of the syntactic foams. In addition, SEM was used to understand the microstructure of the samples tested. Vibration results presented that the presence of carbon nanofiber enhanced strength but was not effective on damping, while low-velocity impact, and tensile test results also demonstrated the same trend.

Effect of carbon nanofibers on electrode performance of symmetric supercapcitors with composite α-MnO2 nanorods

α-MnO2 nanorods have been grown on the surface of carbon nanofibers (CNFs) for enhancing the electrical conductivity of MnO2. We have synthesized α-MnO2/CNF (0–5 wt%) nanocomposites using a co-precipitation method. The x-ray diffraction results confirm the formation of a single phase α-MnO2 and SEM/TEM images reveal the formation of α-MnO2 nanorods, whose size depends on the amount of CNF in the nanocomposite. Both the surface area and electrical conductivity of nanocomposites are found to be strongly influenced by the presence of CNF. While α-MnO2/CNF(1.25 wt%) exhibits the largest surface area (381 m2/g) and only a modest increase in the electrical conductivity compared to pure α-MnO2 nanorods, the α-MnO2/CNF(5 wt%) shows the least surface area (131 m2/g) but an order of magnitude higher electrical conductivity (0.67 S/cm). Cyclic voltammetry measurements show improved performance (higher specific capacitance and better cyclic stability) in all α-MnO2/CNF supercapacitors compared to that of pure α-MnO2. Ragone plot shows that although α-MnO2/CNF(1.25 wt%) exhibits the highest specific capacitance (313 F/g at 1 A/g) and hence the highest energy density of 32.8 Wh/kg, it has the least power density of 4250 W/kg. On the other hand, α-MnO2/CNF(5 wt%) shows the least energy density of 7.9 Wh/kg but with a higher power density of 8478 W/kg compared to α-MnO2/CNF(1.25 wt%). Our studies demonstrate that one can optimize both energy and power densities by controlling the amount of CNF in the nanocomposites.

Strong shear-driven large scale formation of hybrid shish-kebab in carbon nanofiber reinforced polyethylene composites during the melt second flow.

The formation of a hybrid shish-kebab (HSK) structure with different degrees of lamellar orientations was first observed in the solution crystallization of polyethylene (PE) in the presence of carbon nanofibers (CNFs). In this study, PE crystal lamellae were periodically decorated on the surface of CNFs and were aligned approximately perpendicular to the long axes of the CNFs, forming aligned hybrid shish-kebab nanostructures. More importantly, the fascinating structure was directly formed in all regions of the injection molded bars of HDPE/CNF composites, via a gas-assisted injection molding (GAIM), instead of the shell-core structure. In the GAIM process, an intense shear was imposed onto the melt during the melt second flow and drove PE chains to orient along the axes of the CNFs. Then the entropy penalty for PE chains deposited on the CNF surface was drastically decreased. Although the attractive van der Waals interactions were weak, the oriented PE chains could successfully adsorb on the CNF surface due to the decrease of the entropy penalty, therewith the underlayer coating was formed along the axis based on a two-dimensional mode for early nucleation on the CNF surface. Subsequently, subglobules appeared on the ordered structure, which could be regarded as the crystal nucleus. Finally, the oriented PE chains began to epitaxially grow from the subglobules with a folded-chain shape to decrease the polymer surface energy and grew perpendicular to the CNFs long axis, abiding by the "soft epitaxy" crystallization mechanism regardless of strict lattice matching.

Preparation and Characterization of Carbon Nanofiber Composite Coated Fabric-Heating Elements

This study prepared fabric-heating elements of carbon nanofiber composite to characterize morphologies and electrical properties. Carbon nanofiber composite was prepared with 15wt% PVDF-HFP/acetone solution, and 0, 1, 2, 4, 8, and 16wt% carbon nanofiber. Dispersion of solution was conducted with stirring for a week, sonification for 24 hours, and storage for a month, until coating. Carbon nanofiber composite coated fabrics were prepared by knife-edge coating on nylon fabrics with a thickness of 0.1mm. The morphologies of carbon nanofiber composite coated fabrics were measured by FE-SEM. Surface resistance was determined by KS K0555 and worksurface tester. A heating-pad clamping device connected to a variable AC/DC power supply was used for the electric heating characteristics of the samples and multi-layer fabrics. An infrared camera applied voltages to samples while maintaining a certain distance from fabric surfaces. The results of morphologies indicated that the CNF content increased specifically to the visibility and presence of carbon nanofiber. The surface resistance test results revealed that an increased CNF content improved the performance of coated fabrics. The results of electric heating properties, surface temperatures and current of 16wt% carbon nanofiber composite coated fabrics were 80℃ and 0.35A in the application of a 20V current. Carbon nanofiber composite coated fabrics have excellent electrical characteristics as fabric-heating elements.

Enhanced Conductivity and mechanical properties of polyimide based nanocomposite materials with carbon nanofibers via carbonization of electrospun polyimide fibers

Carbon nanofibers (CNF) have been obtained by the thermal treatment of the electrospun polyimide fibers in our present work. The carbon structure and surface morphology of the as-received CNFs were investigated using X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Investigations of the nanocomposite materials fabricated using these CNFs as conductive fillers and polyimide as matrix show that the presence of CNFs can improve both the mechanical and electrical properties of the material. The conductivity of the nanocomposite films increases with increases in the CNF content and a percolation threshold of about 6.3 vol % (0.0785 in weight fraction) is calculated according to percolation theory.

Tensile and Compression Behavior of Woven Glass/Epoxy Nano Composites Based on Spraying Methodology

Nanocomposites have been utilized increasingly because of their high strength, stiffness, toughness, and through-thickness properties. The incorporation of carbon nanofibers with a high aspect ratio and extremely large surface area into glass/epoxy polymer composites improve their tensile and compression properties significantly. Although a number of efforts have been made to improve various properties by mixing nanoparticles directly into resin, however, it could lead to high viscosities which create problems during processing. In this particular study, an attempt has been made to investigate tensile and compression behavior of nanocomposites by using, state of the art, a different technique i.e spraying the Carbon nanoFibers (CNF) on dry woven glass pre-form before infusion. The nanocomposite samples were prepared using a spraying methodology i.e dispersing the 2.0 weight percent CNF solution on glass fabric, and evaporating the solvent such that only nanofibers remain on perform, followed by Vacuum Assisted Resin Transfer Molding (VARTM). Tensile and compression tests were performed to evaluate the effectiveness and behavior of CNF addition on these mechanical properties. Results indicated simultaneous improvement in tensile and compression properties by incorporating a very small amount of carbon nanofibers into the matrix system. 1821 percent improvement in tensile strength and 6-9 percent in compressive strength, with respect to the neat composite. The rise in their modulus has also been discussed in detail and part of this study. For in-depth analysis, microscopic approaches were also carried out to investigate the fracture behavior and mechanism of material. Scanning electron microscopy of fractured surfaces revealed improved primary fibermatrix adhesion and indications of CNF-induced matrix toughening due to the presence of CNFs. SEM evaluation also revealed relatively less damage in the tested fracture surfaces of the nanophased composites in terms of matrix failure, fiber breakage, matrixfiber de-bonding, and de-lamination, compared to the neat system.

Synthesis of Superconducting Nanocables of FeSe Encapsulated in Carbonaceous Shell

The recent discovery of superconductivity in iron selenide has attracted considerable attention due to the simplicity of composition, unconventional nature of superconductivity, and ease of synthesis. We have synthesized superconducting FeSe nanowires with a simple catalyst-aided vapor transport reaction at 800 °C in an inert atmosphere. The precursors were chosen to be elemental Se and iron acetylacetonate [Fe(III)(C₅H₈O₂)₃]. These vaporized very easily, thereby facilitating transport, and also contributed to the formation of a carbonaceous shell encapsulating the FeSe nanowires. The superconductivity of these nanocables was confirmed through magnetic measurements and a T(c) of ≈8 K was obtained for an ensemble of nanocables. The length of FeSe filling inside the carbon nanofibers could be varied by controlling the reaction conditions while the diameter of nanowires was dependent on the thickness of Au-Pd coating used as a catalyst. Extensive analysis through high-resolution microscopy revealed that there was considerable lattice contraction of FeSe in the nanocable up to about 3.6% along the c-direction leading to a reduced spacing between the (001) lattice planes. Interestingly, this compression was more pronounced near the catalyst-FeSe interface and was reduced further along the length of the nanocable. The presence of carbon nanofibers as a shell around the FeSe protected the FeSe nanowires from both atmospheric O₂ and moisture attack, as was evident from the very long ambient condition shelf life of these nanocables, and also makes them more stable under e-beam irradiation.

Thin, Flexible Supercapacitors Made from Carbon Nanofiber Electrodes Decorated at Room Temperature with Manganese Oxide Nanosheets

We report the fabrication and electrochemical performance of a flexible thin film supercapacitor with a novel nanostructured composite electrode. The electrode was prepared byin situcoprecipitation of two-dimensional (2D) MnO2nanosheets at room temperature in the presence of carbon nanofibers (CNFs). The highest specific capacitance of 142 F/g was achieved for CNFs-MnO2electrodes in sandwiched assembly with PVA-H4SiW12O40·nH2O polyelectrolyte separator.

Controlled growth of whisker-like polyaniline on carbon nanofibers and their long cycle life for supercapacitors

We report a facile and efficient method, via chemical polymerization of aniline in the presence of carbon nanofibers (CFs), to fabricate ordered whisker-like polyaniline/CFs nanocomposites. The morphology and microstructure of the obtained composites are characterized by FESEM, TEM, FTIR, Raman, XRD and UV-vis. As a result, PANI nanorods are vertically deposited on the wall of CFs. The composite had a high specific capacitance (427 F g−1) and a super long cycle life (a retention ratio of 90% after 3000 cycles).

A Study of Tribological Properties of Polyphenylene Sulfide Composities Reinforced with CNT and CNF

The tribological properties of polyphenylene sulfide (PPS) composites reinforced with carbon nanotube (CNT) and carbon nanofiber (CNF) were studied. Sliding tests in a pin-on-disk configuration were used to study the tribological properties. The wear rate of reinforced composites in the early part of sliding was lower than that of PPS but over extended sliding the reinforcement was not effective in reducing the wear rate. The coefficient of friction was not greatly affected by the presence of CNF and CNT. The lack of transition from run-in to steady state wear was attributed to the increased wear rates of PPS composites.

Fabrication and Physical Characterization of Biodegradable Poly(butylene succinate)/Carbon Nanofiber Nanocomposite Foams

Nanocomposites of biodegradable poly(butylene succinate) (PBS) and carbon nanofibers (CNFs) were prepared by three different methods, that is, solution blending, melt compounding, and solution and subsequent melt blending (SOAM) method, among which the SOAM method, where nano-scale fillers and polymer matrix are solution-blended and subsequently melt-mixed in a torque rheometer, is a two-step process for obtaining polymer nanocomposite. Dispersion of CNFs in the PBS matrix was characterized by FE-SEM, while thermal and mechanical properties were analyzed by thermogravimetric ananlysis (TGA) and universal test machine (UTM), respectively. The PBS/CNF nanocomposites were then converted to foams by employing a chemical blowing agent (CBA) in the melt. The presence of CNFs increased the melt viscosity of PBS so that the PBS/CNF nanocomposite foams were produced without modifying the chemical structure of the PBS. Nanocomposite foams prepared by the SOAM method showed higher physical properties compared with those prepared by the solution blending and the melt mixing. Cell size and blowing ratio increased with the increase in the CBA content, blowing temperature and time. Cell morphology of the nanocomposite foams was examined by optical microscopy, and the cell size distribution was also investigated.

Effect of polyaniline surface modification of carbon nanofibers on cure kinetics of epoxy resin

AbstractPolyaniline (PANI) “nanograss” was grown on carbon nanofibers (CNFs). The cure behavior of an epoxy resin with and without unmodified CNFs or PANI modified CNFs was studied by means of non‐isothermal and isothermal differential scanning calorimetry (DSC). CNFs accelerated the reaction of epoxy and diamine. PANI surface modification further increased the reaction rate and the extent of reaction. An autocatalytic cure kinetic model was used to fit the reaction curves. It was found that activation energies of the epoxy reaction decreased in the presence of CNFs and PANI modified CNFs. The observed catalytic effect of CNF and PANI surface coating can be very useful for low temperature cure of large epoxy composite products. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010