Synthesis and Characterization of Metal Nanoparticles and the Formation of Metal-Polymer Nanocomposites

2002 ◽  
Vol 740 ◽  
Author(s):  
Anshu A. Pradhan ◽  
S. Ismat Shah ◽  
Lisa Pakstis

ABSTRACTMetal nanoparticles are highly prone to oxidation due to their high surface energy and affinity for oxygen which can lead to the complete oxidation of the particles. Studying and utilizing the unique properties of metal nanoparticles requires minimizing their interaction with the atmosphere. We have used the co-condensation technique to synthesize suspensions of metal nanoparticles in isopropanol. The solvent protects the nanoparticles from the atmosphere and minimizes agglomeration of the nanoparticles. The particles showed a lognormal distribution and the average particle size was below 20nm. Polymer-metal nanocomposites were made by dispersing the metal nanoparticles in PMMA matrix by spin coating and solution casting. Adherent films, fibers and free standing films could be obtained by varying the process conditions. The SEM images show that the nanoparticles in the spun coated films were non-agglomerated and well dispersed over a wide area. Morphology of the spun coated films was different from the solution cast films. Electrically conducting films having interconnected silver particle network could be obtained. Cytotoxicity studies show that the silver nanoparticles and the PMMA-Ag nanocomposite films are antibacterial in nature. We have also dispersed the nanoparticle into pump oil and measured the thermal conductivity of the resultant mixture. The thermal conductivity of the oil could be increased by over 50% by adding an extremely small fraction of the silver nanoparticles.

2019 ◽  
Vol 967 ◽  
pp. 145-149
Author(s):  
Diana Eka Pratiwi ◽  
Sumiati Side ◽  
Nur Aifah Tun Nisa

In recent years, the development of efficient green chemistry methods for synthesis of metal nanoparticles has become a major focus of researchers. One of the most considered methods is production of metal nanoparticles using plants. In this study silver nanoparticles (AgNPs) were rapidly synthesized by reacting silver ions with Moringa oleiferaL. leaf extract. The reaction process was simple and convenient to handle, and was monitored using ultraviolet-visible (UV-Vis) spectrophotometer. The crystalline phase of the AgNPs was determined from X-Ray Diffraction (XRD) patterns. The UV-vis spectra gave surface plasmon resonance for synthesized AgNPs at 465-473 nm. The XRD analysis showed that AgNPs are crystalline in nature and have face centered-cubic geometry with average particle size of 32 nm.


Author(s):  
Guru Kumar Dugganaboyana ◽  
Chaitra Kyasandra Eranna

The green synthesis of nanoparticles has emerged as a cost-effective and environmentally benign technique for therapeutic applications. Nanomedicine utilizes biocompatible nanomaterials for diagnostic and therapeutic potential for various biomedical applications. Different biological methods are gaining recognition over the physical and chemical methods of synthesis for the production of silver nanoparticles (AgNPs) due to their multiple applications. The present study describes the synthesis of AgNPs using the fruit extract of Simaroubaamara (S. amara)followed by characterization of AgNPswas done using different methods, which include; ultraviolet-visible spectroscopy (UV-Vis) wherein it shows absorption peak at 410 nm confirming the AgNPs, from dynamic light scattering (DLS) the average particle size is 80nm with crystalline structure confirmed by scanning electron microscope (SEM) images and zeta potential analysis shows the positive polarity of the particle favoring the drug targeting. The powder X-ray diffraction study (PXRD) revealed crystalline nature with a face-centered cubic (fcc) structure of AgNPs. The synthesized AgNPs were also tested for antioxidant therein the particles could scavenge the stable free radical 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) of about 80% to that of positive control butylated hydroxytoluene (BHT) and antimicrobial studies indicated its microbicidal efficacy against both Gram positive and negative clinical pathogens. It could be concluded that Simaroubaamara fruit extract can be used efficiently in the production of potential antioxidant and antimicrobial AgNPs for commercial application.


2021 ◽  
Vol 6 (1) ◽  
pp. 32-36
Author(s):  
Anh Quoc Le ◽  
Van Phu Dang ◽  
Ngoc Duy Nguyen ◽  
Kim Lan Nguyen Thi ◽  
Kim Lang Vo Thi ◽  
...  

Silver nanoparticles (AgNPs) doped in the zeolite framework (AgNPs/Z) were successfully synthesized by γ-irradiation in ethanol solution of silver ion-zeolite (Ag+/Z) prepared by ion exchange reaction between silver nitrate (AgNO3) and zeolite 4A. The effects of the Ag+ concentration and irradiation dose on the formation of AgNPs/Z were also investigated. AgNPs/Z with the silver content of about 10,000 ppm and the average particle size of AgNPs of about 27 nm was characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM). Firstly, AgNPs/Z was added into PP resins for creation of PP-AgNPs/Z masterbatch (Ag content of ~10.000 ppm) and then PP-AgNPs/Z plastics were preapared by mixing masterbatch with PP resins. The antibacterial activity of the PP-AgNPs/Z plastics was investigated against Gram-negative bacteria Escherichia coli (E. coli). The results showed that PP-AgNPs/Z plastic contained 100 ppm of Ag possessed a high antibacterial property, namely the bactericidal effect was more than 96 % on the platic surface. In conclusion, possessing many advantages such as: vigorously antibacterial effect and good dispersion in plastic matrix, AgNPs/Z is promising to be applied as bactericidal agent for plastic industry.


2019 ◽  
Vol 13 (3) ◽  
pp. 234-240
Author(s):  
Elnaz Moslehifard ◽  
Mahmood Robati Anaraki ◽  
Saeed Shirkavand

Background. The current study evaluated the compressive, flexural and impact strengths of heat-cured acrylic resins reinforced by TiO2 nanoparticles (NPs). Methods. TiO2 NPs were provided and characterized using scanning electron microscopy (SEM) to determine their morphology and crystalline structure. For three mechanical tests, 12 acrylic resin groups (n=9), totaling 108 specimens, were prepared using a special mold for each test, with TiO2 nanoparticle contents of 0, 0.5, 1 or 2 wt% in different groups. After curing, the compressive, flexural and impact strengths of the specimens were examined according to ISO 1567. Results. In the SEM and XRD study of TiO2 NPs, anatase was identified as the major crystalline phase followed by rutile (average particle size: 20.4 nm). SEM images showed that the nanocomposite with 1 wt% NPs had a more homogenized blend. 1 wt% TiO2 nanocomposite exhibited a higher, but non-significant, impact strength compared to the controls. ANOVA showed significant differences in the impact and flexural strengths between nanocomposites with various contents of TiO2 NPs. Conclusion. The nanocomposite with 1 wt% TiO2 NPs exhibited fewer micro-pores and micro-cracks in the SEM cross-sections. A non-significant increase was also observed in the impact strength with TiO2 NPs at 1 wt%. Further increase in TiO2 NPs decreased both the impact and flexural strengths. The compressive strength of the heat-cured acrylic resin was not affected by the incorporation of NPs.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Indrawati Patabang ◽  
Syahruddin Kasim ◽  
Paulina Taba

Silver nanoparticles have been synthesized using kluwak leaf extract (Pangium edule Reinw) as bioreductor and antioxidant activity assay. The nanoparticles formed were monitored by observing UV-Vis absorption and characterized by using FTIR, PSA, XRD and SEM instruments. The result of functional group characterization with FTIR show that the functional groups OH, C = O, C-O and CH2 act as Ag+ reducing agent. The size of silver nanoparticles was determined by using Particle Size Analyzer (PSA) and the result show average particle size distribution of 93.2 nm. Morphology of AgNp were observed by Scanning Electron Microscope (SEM) and X-Ray Difraction (XRD) analysis show result of 51,78 nm. The antioxidant activity was shown by in kluwak leaf extract and silver nanoparticles with IC50 values respectively 831,33 ppm dan 1493,09 ppm.


2010 ◽  
Vol 5 (3) ◽  
pp. 155892501000500 ◽  
Author(s):  
D.P. Chattopadhyay ◽  
B.H. Patel

This research deals with the synthesis of nanosized copper as colloidal solution and its application to cotton fabric. Copper nano colloids were prepared by chemical reduction of copper salt using sodium borohydride as reducing agent in presence of tri-sodium citrate. The size and size distribution of the particles were examined by particle size analyzer and the morphology of the synthesized particles was examined by SEM and AFM techniques. X-ray fluorescence spectroscopy detected the presence of copper in the treated fabric. The results of particle size analysis showed that the average particle size varied from 60 nm to 100 nm. The nano copper treated cotton was subjected to soil burial test for the assessment of its resistance towards microbial attack. SEM images of treated fabric indicate copper nano particles are well dispersed on the surface of the specimens. The treatments of nano copper colloidal solution on cotton not only improve its antimicrobial efficiency but also influenced the tensile strength of the fabric sample positively. The treatment was found to enhance the color depth and fastness properties of direct dyed cotton fabric samples.


2019 ◽  
Vol 19 (11) ◽  
pp. 7487-7492 ◽  
Author(s):  
Supriya ◽  
Jayanta Kumar Basu ◽  
Sonali Sengupta

Synthesis of silver nanoparticles embedded on calcium alginate film and the catalytic property of this film in the reduction of nitrobenzene with sodium borohydride are demonstrated in this work. Natural polymer alginate acts as effective reducing and stabilizing agent in synthesis of silver nanoparticles. Effect of different parameters on the preparation of silver nanoparticles, such as, temperature, concentration of silver precursor and heating time was investigated. As-prepared silver nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, UV-Vis spectrometry, and atomic absorption spectrometry. Transmission electron microscopy analysis con-firms the formation of silver nanoparticles with particles size range of 3–19 nm and average particle size was found to be 10±4 nm. Effect of concentration of nitrobenzene and sodium borohydride, catalyst loading and temperature on the catalytic reduction of nitrobenzene was studied. Reusability of catalyst was examined in this reduction reaction and the catalyst shows good activity up to 10th run.


Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1057
Author(s):  
Jesús Hidalgo-Carrillo ◽  
Juan Martín-Gómez ◽  
M. Carmen Herrera-Beurnio ◽  
Rafael C. Estévez ◽  
Francisco J. Urbano ◽  
...  

Olive leaves (by-product from olive oil production in olive mills) were used as biotemplates to synthesize a titania-based artificial olive leaf (AOL). Scanning electron microscopy (SEM) images of AOL showed the successful replication of trichomes and internal structure channels present in olive leaves. The BET surface area of AOL was 52 m2·g−1. X-ray diffraction (XRD) and Raman spectra revealed that the resulting solid was in the predominantly-anatase crystalline form (7.5 nm average particle size). Moreover, the synthesis led to a red-shift in light absorption as compared to reference anatase (gap energies of 2.98 and 3.2 eV, respectively). The presence of surface defects (as evidenced by X-ray photoelectron spectroscopy, XPS, and electron paramagnetic resonance spectroscopy, EPR) and doping elements (e.g., 1% nitrogen, observed by elemental analysis and XPS) could account for that. AOL was preliminarily tested as a catalyst for hydrogen production through glycerol photoreforming and exhibited an activity 64% higher than reference material Evonik P25 under solar irradiation and 144% greater under ultraviolet radiation (UV).


MRS Advances ◽  
2020 ◽  
Vol 5 (45) ◽  
pp. 2349-2358 ◽  
Author(s):  
S. K. Noukelag ◽  
H.E.A. Mohamed ◽  
B. Moussa ◽  
L.C. Razanamahandry ◽  
S.K.O. Ntwampe ◽  
...  

AbstractBiosynthesized Zincite nanoparticles have been successfully demonstrated by a completely green process mediated aqueous extract of rosemary leaves acting as both reducing and stabilizing agents and zinc nitrate hexahydrate as the precursor. The synthesis was free of solvents and surfactants to adhere to green chemistry principles and the impartation of environmental benignity. To achieve our objective, structural and optical investigations of ZnO annealed at 500°C for 2hrs were carried-out using complementary techniques. High resolution transmission electron microscopy (HRTEM) revealed the self-assembled, highly agglomerated quasi-hexagonal shaped NPs and the average particle size was found to peak at 15.62 ± 0.22 nm. Selected area electron diffraction (SAED) and X-ray diffraction (XRD) exhibited several diffraction rings with clear diffraction spots confirming their polycrystallinity and the purity of ZnO NPs with a wurtzite structure. Furthermore, the energy dispersive X-ray spectroscopy (EDS) substantiated the presence of Zn and O in the sample and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) illustrated the Zn-O chemical bonds. From UV-Vis-NIR, the optical band gap was amounted to 3.2 eV and photoluminescence (PL) emission spectrum to 2.9eV with high surface defects and oxygen vacancies. Through these results, the use of rosemary leaves extract is hereby shown to be a cost-effective and environmentally friendly alternative to synthesize Zincite nanoparticles (ZnO NPs).


2018 ◽  
Vol 382 ◽  
pp. 352-356 ◽  
Author(s):  
Supitcha Rungrodnimitchai ◽  
Sirinapa Mayod ◽  
Sutamma Tanasarn

In this study, ground tire rubber (R-GTR) with the average particle size of 456 µm was chemically modified to produce modified ground tire rubber (M-GTR) that can work as ion exchange materials. The modification was performed by oxidation reaction. The ground tire rubber was oxidized at the range of temperature from 20 to 40๐C for 48, 72 and 96 hours by a mixture of the HNO3/H3PO4/NaNO2system. The HNO3/H3PO4ratio was 1:3 and the concentration of NaNO2was 1.4% w/v. FT-IR revealed that the carboxyl group or the carbonyl group was successfully introduced into the modified ground tire rubber and SEM images demonstrated that the porosity of modified ground tire rubber increased. The results of the modified ground tire rubber showed that the carboxyl content increased with an increase of reaction time while %yield decreased with an increase of reaction time. The optimum condition for modification was the reaction at 30๐C for 96 hours.


Sign in / Sign up

Export Citation Format

Share Document