Papers by Keyword: Copper Nanoparticles

Abstract: Natural magnetic particles/chitosan/CuNPs (NMP/Chi/CuNPs) have been successfully synthesized in green chemistry by impregnation of copper nanoparticles (CuNPs) on the composite of natural magnetic particles/chitosan (NMP/Chi). Copper nanoparticles were prepared using Cu(II) solutions with varying concentrations (5, 10, 15, 20, and 25 mM). The synthesis of CuNPs was carried out by chemical reduction with ascorbic acid as a reducing agent and chitosan as a capping agent using microwave heating. The formation of copper nanoparticles was indicated with a peak at 580-590 nm, and the optimum absorbance was obtained at a precursor concentration of 20 mM using a UV-Vis spectrophotometer. The NMP/Chi/CuNP(20) composite material was characterized using Fourier Transform-Infra Red (FTIR) to confirm the interaction between NMP/Chi and CuNP(20). Crystal analysis by X-Ray Diffraction (XRD) showed the highest characteristic peak of Fe₃O₄ at 2θ angle 35° where the peak intensity at NMP/Chi/CuNP(20) decreased compared to NMP and NMP/chi. The mean crystallite sizes of NMP and NMP/Chi were obtained at 8.33 nm and 64.95 nm, respectively. Morphology and elemental composition of composite materials with Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX) showed that CuNP 20 was successfully impregnated in NMP/Chi and contained the main elements, namely C, N, O, Fe, and Cu. Using TEM analysis, the shape of the NMP/Chi/CuNP(20) particles is similar to that of CuNP(20), which is spherical, and the particle size was 32.95 nm. The material is potential as an easily separable antibacterial agent in water using an external magnet.

Abstract: Polyphenylene sulfide (PPS) fiber is widely used in the fields of high-temperature filtration, protective clothing, electronics, automobile, and aircrafts sectors relying on its excellent heat and chemical resistance. However, PPS fiber is easily oxidized under high temperature, which vastly restricts its applications. In this study, using the copper nanoparticles loaded halloysite nanotubes (HNTs@Cu) as a nanofiller, we prepared a PPS composite fiber with improved oxidation resistance. The successful loading of copper nanoparticles into HNTs was demonstrated through TEM and elemental analysis. The crystallinity, orientation, thermal and mechanical properties of PPS nanocomposite fibers were investigated via DSC, XRD, WXRD, TGA and mechanical test. While the mechanical performance of the composite fibers was slightly decreased, the thermal stability was improved when comparing to the neat PPS fiber. The composite fiber with 1.0 wt.% loading of HNTs@Cu showed an over 100% retention rate of breaking strength after thermal oxidative aging, suggesting an improvement in oxidation resistance of PPS fiber. This work provides an effective and accessible method for improving the thermal stability and oxidation resistance of PPS fibers, which thereby helps to extend the applications of PPS fibers in high temperature environment.

Abstract: The antimicrobial functionalization of polyester fabrics (PES) is useful to provide protection from pathogens and reducing odors. Copper nanoparticles (CuNPs) have been widely applied due to their antimicrobial properties and higher biocompatibility compared with other metal nanoparticles. However, the inherent instability of CuNPs under atmospheric conditions and the use of harmful chemicals during their synthesis limit their use. Thus, the development of efficient and safe methods for the CuNPs synthesis and their stabilization onto surfaces present high interest. In this work, PES was functionalized with CuNPs via in situ synthesis using cost-effective and safe chemicals in the presence and absence of chitosan. In sample without chitosan, the CuNPs showed a suitable stabilization onto PES due to the doubled stabilization of ascorbic acid (AA) and cetyl trimethyl ammonium bromide (CTAB). In sample with chitosan, less CuNPs were retained by the PES but also less CuNPs agglomeration was observed. Both samples presented excellent antibacterial effect against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) as well as laundering durability.

Abstract: Copper nanopowders were obtained by the gas-phase method under the influence of an electron beam of different powers. Thermodynamic modeling of the phase equilibrium state of the Cu-O2-C system during heating in argon and atmospheric pressure was carried out using the TERRA software package. The obtained nanopowders of copper were studied by X-ray phase analysis and transmission electron microscopy. The morphology, structure, size distribution, and average size of copper nanoparticles are determined. The dependence of the content of copper oxides in a copper-containing nanopowder on the electron beam power has been established. It is shown that copper nanopowders obtained at high power are not oxidized.

Abstract: The copper nanoparticles were obtained by evaporating the metal by the relativistic electron beam. The average size of synthesized particles was about 120 nm. They were characterized by X-ray diffraction, transmission electron microscopy. The results of the X-ray diffraction showed high content of the pure copper for closed setup with an inert gas. Transmission electron microscopy cleared some particles to have an icosahedral structure. These nanoparticles were obtained when the target was exposed by the beam with the highest current strength used in the experiment and the highest cooling of the copper vapor. The process of copper nanoparticle formation by the molecular dynamic method using EAM – potentials (potentials in the Embedded Atom Method form) was studied.

Abstract: In this paper described the possibility for using the copper nanoparticles as additives to lubricating oil. Copper nanoparticle has a decreased melting point and low shearing strength, therefore, the particles exhibit a high degree of slip. Adding copper nanoparticles to lubricating oil, can reduce the friction and wear of the friction surfaces, increase engine power, while reducing air pollution with an increase operating life of the engine. In this paper also described the liquid reduction process as a method for copper nanoparticle manufacture, which can be carried out without expensive special equipment. Generally in the process of gathering products – nanoparticles need to use the ultracentrifuge, and there is the phenomenon of aggregation of nanoparticles. In this paper obtained copper nanoparticles with dimensions of 30-80 nm without using the ultracentrifuge by adding organic solvent to a solution of the reduction reaction. Also presented the test results for friction and wear of the parts in the environment of the lubricating oil added copper nanoparticles. The experimental test results confirmed the theoretical assumption that copper nanoparticles improve the operational properties of the oil and reduce the abrasion of the surface of friction parts.

Abstract: In this study, the antimicrobial growth inhibition and mechanistic activities of silver (Ag NPs), zinc oxide (ZnO NPs), and copper (Cu NPs) nanoparticles were investigated in presence of medicinal plant extracts of Tribulus Terrestris. The extract in different concentrations (5, 10, 20, and 30%) along with nanoparticles suspension mixture was used for antimicrobial activity testing against some human pathogenic microorganisms. Among the bacterial strains tested, Escherichia coli and Proteus sp were most susceptibile at 30% concentration followed by moderate activity against Morganella sp, Entrococcus Faecalis, Staphylococcus aureus, and Candida albicans. Tribulus Terrestris had no effect on Acetobacter sp and Streptococcus agalactia. The nanoparticles used in the present investigation have shown excellent antimicrobial activity in the presence of Tribulus Terrestris, hence they can be used as potent sources for antibacterial agents.

Abstract: Commercially available conductive inks are typically made up of precious metal nanoparticles, such as gold (Au) and silver (Ag). Thus, cheaper metals like copper (Cu) are currently being explored as alternative material. Though Cu has a comparable conductivity to that of Ag, they tend to oxidize easily when exposed to air and water, which could limit their application. In this work, oxidation-stable Cu nanoparticles with mean diameter as small as 57 nm were prepared by simple electroless deposition in water. Food-grade gelatin was used as stabilizer, which makes the process more economical and environment-friendly. In situ monitoring of mixed potential was carried out during synthesis to understand the kinetics of the reaction. The mixed potential of the solution shifted negatively as the amount of gelatin was increased. This suggests faster reduction rate.

Abstract: Oxidation-stable copper (Cu) nanoparticles have been successfully prepared by electroless deposition in water at 353 K. Cupric oxide (CuO) and hydrazine (N₂H₄) are employed as the Cu precursor and reducing agent, respectively. The Cu nanoparticles have uniform particle sizes with average values ranging from 37 to 43 nm. The addition of gelatin has played a vital in role in controlling the particle size, agglomeration, and oxidation of Cu nanoparticles. In the absence of gelatin, both metallic Cu and cuprous oxide (Cu₂O) are present in the sample, indicating incomplete reduction of the CuO. Pure metallic Cu nanoparticles with excellent oxidation and dispersability in water can only be formed when gelatin is employed as protective agent. At higher amounts of gelatin, the particle size of the Cu nanoparticles is reduced.

Abstract: The copper nanoparticles were synthesized by green technology using leaf extracts of Ocimum sanctum. The synthesized copper nanoparticles were confirmed by the change of colour after the addition of leaf extract into the copper sulfate solution. The synthesized copper was characterized by X-ray Diffraction (XRD), transmission electron microscopy (TEM) and UV-vis absorption spectroscopy. The copper nanoparticles are crystallized with FCC structure. The synthesized copper nanoparticles exhibit spherical morphology with average particle size of 20 nm. The copper nanoparticle exhibits absorption broad band between 550 nm – 575 nm. The optical trapping effect of Gaussian beam acting on a copper nanoparticle in Rayleigh regime was studied. The optical scattering and optical gradient forces were calculated for 20 nm copper particle.