Papers by Keyword: Carbon Nanoparticles

Abstract: Polymer composite materials based on thermoplastic polymer and carbon nanoparticles with different axial ratio were obtained by melt technology. The values of the electrical resistance of polymer composites have been determined. Development of a methodology for assessing the parameters of the percolation process: the percolation threshold and the required resistance values of the polymer, to obtain a material with antistatic properties.

Abstract: In the present work, fibers based on heat-resistant amorphous polyimide brand Ultem-1000 were prepared by melt extrusion. Vapor-grown carbon nanofibers (VGCFs) and single-wall carbon nanotubes (SWCNTs) were used to increase the mechanical characteristics of the polymer fibers. The fibers were characterized by scanning electron microscopy (SEM), thermophysical and mechanical tensile analysis. SEM study revealed very good distribution of the carbon nanofillers throughout the polyimide fiber volume. The mechanical testing of the unoriented nanocomposite fibers showed that the introduction of VGCFs or SWCNTs led to an increase in tensile strength and modulus. High-temperature drawing allows obtaining polyimide nanocomposite fibers with significantly increased mechanical properties (»300 MPa for strength and »4.6 GPa for modulus).

Abstract: Polymer composite materials based on polypropylene matrix and carbon nanoparticles of various shapes: spherical particles - carbon black and anisotropic nanoparticles - carbon nanofibers, were obtained by the melt technology. A character of the dependences of the electrical conductivities on the concentration of carbon nanofillers has been revealed. A simulation of the electrical conductivity of the polymer composite in the region of the concentration of the filler at the threshold of the flow of electric current and below it was carried out.

Abstract: This study describes the structural modifications of char electrodes and the resulting carbon nanoparticles using method of arc discharge in liquid method, an approach which is simpler and less expensive than other techniques such as CVD and laser vaporization. The nanoparticles are obtained from powder floating on the water surface during arc discharge between two electrodes submerged in water. X-ray diffraction analysis (XRD) profiles show peak formation at 24-26^o 2Ѳ, associated with hexagonal graphite structure.Transmission electron microscopy (TEM) confirmed the presence of graphitic-structured nanoparticles after arc discharge; these nanoparticles have diameters ranging from 20 to 100 nm. In contrast, nanoparticles produced using graphite electrodes with current source variations show more complicated and varied stuctures, for example, structures such as nanoonions, graphene, and amorphous nanoparticles.

Abstract: Carbon nanoparticles (CNPs) were successfully synthesized from the mixture of used motor oil and benzene via a solution plasma process (SPP). The synthesis was achieved within a single step at room temperature and atmospheric pressure. The effects of mixing ratio between used motor oil and benzene on the physical and chemical properties of CNPs were investigated by means of field-emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Raman spectroscopy. The results revealed that there were no significant changes in morphological feature and chemical functional groups on CNPs at different mixing ratios. The CNPs exhibited the aggregates of fine particles with the diameter of about 20–30 nm. The crystallinity of CNPs was found to be slightly increase when synthesized under the presence of used motor oil, possibly due to the effect of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons in used motor oil. We expect that the conversion of used motor oil into CNPs by SPP could be another attractive way to add the value to used motor oil prior to disposing.

Abstract: Concrete is a very important composite for making different building structures to absorb different levels of radiation. Nuclear power plants, nuclear research reactors, particle accelerators and linear accelerator in medical institution use concrete in building construction. Nanoparticles or nanocrystals have different properties than their bulk counterparts. The gamma radiation absorption characteristics and beta back scattering by nanoparticles is also different than their counterparts. In this paper, carbon nanoparticles are mixed in the concrete composite during its preparation. The concrete composite with carbon nanoparticles as admixture were analyzed to provide radiation protection. The gamma radiation absorption characteristics and beta back scattering in ordinary and carbon nanoparticles contained concretes have been studied by GM counter. The results show that using carbon nanoparticles as an admixture in the concrete is one of the solutions for gamma ray shielding and beta back scattering. Therefore, it is good to use carbon nanoparticles as admixtures in concrete composites for beta and gamma radiation scattering and absorption respectively.

Abstract: Co-pyrolysis of slop oil with ferrocene was carried out to convert waste of petroleum into carbon nanoparticles (CNPs). Since slop oil is a mixture of hydrocarbons (HCs) with broad molecular weight distribution, it could be simply fractionated into some certain fractions by batch distillation. Distillate containing hydrocarbons with small molecules was mainly focused as an alternative carbon source for synthesis of CNPs. A two-stage furnace was employed for evaporating a mixture of distillated slop oil and ferrocene at 200 °C in the 1^st stage of the furnace and then formation of CNPs at 900 °C could be observed in the 2^nd stage. Laboratory-grade ferrocene was mixed with slop oil with a designated weight-ratio of 1:2. Microscopic analyses based on SEM and TEM micrographs reveals that CNPs obtained from distillated slop oil mostly consist of bundles of multi-walled carbon nanotubes (MWCNTs) with nominal diameters of 20-50 nm. Raman spectroscopic analyses of the synthesized CNPs exhibit the notably high value of I_G/I_D, suggesting that the synthesized CNPs preferably consist of graphitic nanostructure. Moreover, TGA analysis shows that 39.8 and 32.9 wt% of Fe contents exist in the CNP samples synthesized from original slop oil and distillated slop oil, respectively.

Abstract: carbon nanoparticles (CNPs ) prepared by electrochemical oxidation method possesses high surface activities, and based on strong affinities between water-soluble CNPs and fluorescent molecules, the mechanisms of fluorescence quenching towards Conjugated Polymers (CPs) was discussed, and CNPs could acted as a nanoquenchor for biochemistry application, such as detection of DNA molecules and other biomolecules by the similar way.

Abstract: This work concern the research of the concentration dependences of the influence the micro amounts of the fine disperse silica fume and the carbon nanoparticles containing modifiers on the mobility of the fine-aggregate concrete mixtures and on the pressure strength of concrete. It was founded the high nonlinear dependences of increasing this parameters in the region of the concentration 10^-3 – 10^-6 % of the mass of concrete. This results provide the possibility to approach the industry application for the high performance concretes technology at the nearest time.

Abstract: Hierarchical SAPO-11 moelecular sieves were hydrothermally synthesized in the presence of carbon nanoparticles. X-ray diffraction (XRD) and N₂ adsorption-desorption analysis were conducted, which showed that samples prepared with carbon nanoparticles exhibited AEL structure with mesopores centering at 30nm. The product was also characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which showed that the crystal surface became rough and left the mesopore structure with mesopore volume of 0.339 cm³/g after carbon template being burned off. For the hydroisomerization reaction of n-dodecane, the hierarchical SAPO-11 catalyst showed higher isomer and monobranched product selectivity than the traditional SAPO-11, which would be beneficial for n-paraffin upgrading.