Synthesis of Nanostructured Magnetic Mixed-Oxide Ferrite Powders by Using A Novel Chemical Method

2002 ◽  
Vol 720 ◽  
Author(s):  
N N Ghosh
Keyword(s):  
Particle Size ◽  
Mixed Oxide ◽  
Chemical Method ◽  
Average Particle Size ◽  
Cost Effective ◽  
Water Soluble ◽  
Average Particle ◽  
Chemical Route ◽  
Water Soluble Polymer ◽  
Different Temperatures

AbstractIn the present investigation, an attempt has been made to establish a new chemical route for synthesis of the nanostructured mixed oxide ferrite powders. By using this chemical method a variety of ferrite powders having spinel structure and doped with Co, Ni, Mn, Zn etc has been prepared. In this method nitrate salts of the different metals were used as starting materials. The aqueous solutions of the metal nitrates were mixed according to the molar ration of the compositions. Then the mixtures were mixed with an aqueous solution of water soluble polymer (polyvinyl alcohol). This mixture after drying yield fluffy brown powders. These powders were then calcined at different temperatures ranging from 400 °C to 700 °C. Nanostructured powders were obtained from the thermal decomposition of the brown powders. The powders, prepared by calcinations at different temperatures, were characterized by using X-Ray diffraction analysis, IR spectroscopy, TGA/DTA, and TEM. It was observed that the average particle size of the powders are in nanometer scale with a narrow size distribution. The average particle size of the powders was increased with the increase of calcinations temperature.This chemical method has proved to provide a convenient process for the preparation of nanostructured ceramic powders at comparatively low temperatures and offers the potential of being a simple and cost-effective route.

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

scholarly journals Modeling of Miniemulsion Polymerization of Styrene with Macro-RAFT Agents to Theoretically Compare Slow Fragmentation, Ideal Exchange and Cross-Termination Cases

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 320 ◽  
Author(s):  
Dries Devlaminck ◽  
Paul Van Steenberge ◽  
Marie-Françoise Reyniers ◽  
Dagmar D’hooge
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Miniemulsion Polymerization ◽  
Monomer Conversion ◽  
Water Soluble ◽  
Explicit Calculation ◽  
Average Particle ◽  
Intermediate Radical ◽  
Raft Agent ◽  
The Impact

A 5-dimensional Smith-Ewart based model is developed to understand differences for reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerization with theoretical agents mimicking cases of slow fragmentation, cross-termination, and ideal exchange while accounting for chain length and monomer conversion dependencies due to diffusional limitations. The focus is on styrene as a monomer, a water soluble initiator, and a macro-RAFT agent to avoid exit/entry of the RAFT leaving group radical. It is shown that with a too low RAFT fragmentation rate coefficient it is generally not afforded to consider zero-one kinetics (for the related intermediate radical type) and that with significant RAFT cross-termination the dead polymer product is dominantly originating from the RAFT intermediate radical. To allow the identification of the nature of the RAFT retardation it is recommended to experimentally investigate in the future the impact of the average particle size (dp) on both the monomer conversion profile and the average polymer properties for a sufficiently broad dp range, ideally including the bulk limit. With decreasing particle size both a slow RAFT fragmentation and a fast RAFT cross-termination result in a stronger segregation and thus rate acceleration. The particle size dependency is different, allowing further differentiation based on the variation of the dispersity and end-group functionality. Significant RAFT cross-termination is specifically associated with a strong dispersity increase at higher average particle sizes. Only with an ideal exchange it is afforded in the modeling to avoid the explicit calculation of the RAFT intermediate concentration evolution.

Polyaniline: Thin films and colloidal dispersions (IUPAC Technical Report)

2005 ◽  
Vol 77 (5) ◽  
pp. 815-826 ◽  
Author(s):  
Jaroslav Stejskal ◽  
Irina Sapurina
Keyword(s):  
Thin Films ◽  
Dispersion Polymerization ◽  
Average Particle Size ◽  
Colloidal Dispersions ◽  
Water Soluble ◽  
Average Particle ◽  
Water Soluble Polymer ◽  
Ammonium Peroxydisulfate ◽  
Technical Report

Several workers from various institutions in six countries have prepared thin films and colloidal polyaniline dispersions. The films were produced in situ on glass supports during the oxidation of anilinium chloride with ammonium peroxydisulfate in water. The average thickness of the films, assessed by optical absorption, was 125 ± 9 nm, and the conductivity of films was 2.6 ± 0.7 S cm–1. Films prepared in 1 mol l–1 HCl had a similar thickness, 109 ± 10 nm, but a higher conductivity, 18.8 ± 7.1 S cm–1. Colloidal polyaniline particles stabilized with a water-soluble polymer, poly(N-vinylpyrrolidone) [poly(1-vinylpyrrolidin-2-one)], have been prepared by dispersion polymerization. The average particle size, 241 ± 50 nm, and polydispersity, 0.26 ± 0.12, have been determined by dynamic light scattering. The preparation of these two supramolecular polyaniline forms was found to be well reproducible.

scholarly journals Surface Characterization and Thermodynamics of Adsorption of Pr, Nd and Er on Alumina from Aqueous Solution

1992 ◽  
Vol 9 (1) ◽  
pp. 17-29 ◽  
Author(s):  
M. Saleem ◽  
M. Afzal ◽  
F. Mahmood ◽  
A. Ali
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Free Energy ◽  
Adsorption Isotherms ◽  
Surface Characterization ◽  
Average Particle Size ◽  
Average Particle ◽  
Enthalpy Of Adsorption ◽  
Different Temperatures ◽  
Isotherm Equations

The porous nature of alumina has been investigated using various techniques. The values obtained for moisture content, surface area, pore volume, average particle size and porosity were 22%, 116 m2/g, 0.76 cm3/g, 17.0±0.5 μm and 68.0%, respectively. The adsorption isotherms of NdIII, PrIII and ErIII on alumina from aqueous solution have been obtained at different temperatures. All these adsorption isotherms obey the Langmuir, Freundlich and Dubinin-Radushkevich isotherm equations. Thermodynamic parameters such as the free energy, entropy and enthalpy of adsorption have been computed and interpreted. It is noteworthy that the adsorption of PrIII and NdIII increases with decreasing temperature while the reverse is observed for ErIII.

Synthesis and properties of novel self-crosslinked cationic fluorinated acrylic latex prepared with novel emulsified system

2016 ◽  
Vol 45 (4) ◽  
pp. 259-264
Author(s):  
Wen Li ◽  
Zhongbin Bao ◽  
Lijun Chen ◽  
Dongshun Deng
Keyword(s):  
Particle Size ◽  
Gemini Surfactants ◽  
Average Particle Size ◽  
Water Soluble ◽  
Average Particle ◽  
Mixed Surfactants ◽  
The Novel ◽  
Content Type ◽  
Acrylic Latex ◽  
Emulsion Polymerisation

Purpose At present, the conventional method of preparing cationic fluorinated acrylic latex is to emulsify copolymerised monomers with cationic surfactants. However, there has been a wide concern about using Gemini surfactants to prepare cationic polymer latex to improve its properties. The purpose of this paper was to focus on the synthesis of novel self-crosslinked cationic fluorinated acrylic latex (SCFAL), during which the copolymerised monomers were initiated with a water soluble azo initiator and emulsified with mixed surfactants of Gemini emulsifier and alkyl polyglycoside (APG). Design/methodology/approach The novel SCFAL was prepared successfully by the semi-continuous seeded emulsion polymerisation of butyl acrylate, methyl methacrylate, hexafluorobutyl methacrylate (HFMA) and hydroxy propyl methacrylate (HPMA) in aqueous medium. Findings The conversion is the maximum and the coagulation percentage the minimum when the amounts of emulsifier and initiator are 8 and 0.6 per cent, respectively. The average particle size of the latex is significantly reduced with the increase of the amount of emulsifiers used. However, the average particle size of the latex is increased with the increase of the amount of HPMA. The particle size of the latex is of a unimodal distribution, which means that the particle size was reasonably uniform. Contact angle is increased with the increase of the amount of the HFMA. Practical implications The novel SCFAL can be widely used as significant components in the field of coatings, leather, textile, paper, adhesives and so on. Originality/value SCFAL, which was emulsified with novel mixed surfactants of Gemini surfactant and APG, has been prepared successfully. Influences of amount of initiator, emulsifier, HPMA and HFMA on emulsion polymerisation and/or properties of novel latex are investigated in detail.

scholarly journals INVESTIGATION ON DISSOLUTION PATTERN AND MATHEMATICAL MODELING OF DRUG RELEASE OF QUERCETIN BY COMPLEXATION WITH CYCLODEXTRIN NANOSPONGES

2019 ◽  
pp. 260-264
Author(s):  
SOBITHARANI P ◽  
ANANDAM S ◽  
MOHAN VARMA M ◽  
VIJAYA RATNA J ◽  
SHAILAJA P
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Average Particle Size ◽  
Particle Size Analysis ◽  
Water Soluble ◽  
Size Analysis ◽  
Average Particle ◽  
Scattering Method ◽  
Release Pattern ◽  
Cyclodextrin Nanosponges

Objective: The main objective of this study was to investigate the release pattern of a poorly water-soluble drug quercetin (QU) by fabricating its cyclodextrin nanosponges. Methods: Characterization of the original QU powder and QU-loaded nanosponges was carried out by the Fourier-transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and dissolution tester. The drug release pattern was subjected to various kinetic models. Results: FTIR studies confirmed the formation of inclusion complex of drug. The particle size analysis revealed that the average particle size measured by laser light scattering method is around 400–420 nm with low polydispersity index. The particle size distribution is unimodal and having a narrow range. A sufficiently high zeta potential indicates that the complexes would be stable and the tendency to agglomerate would be miniscule. TEM image revealed the porous nature of nanosponges. The dissolution of the QU nanosponges was significantly higher compared with the pure drug. Conclusion: From the kinetic study, it is apparent that the regression coefficient value closer to unity in case of Korsmeyer-Peppas model indicates that the drug release exponentially to the elapsed time. n value obtained from the Korsmeyer-Peppas plots, i.e., 0.9911 indicating non-Fickian (anomalous) transport ; thus, it projected that delivered its active ingredient by coupled diffusion and erosion.

scholarly journals Growth of significantly low dimensional zinc orthotitanate (Zn2TiO4) nanoparticles by solid state reaction method

2018 ◽  
Vol 50 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Lizina Khatua ◽  
Rudrashish Panda ◽  
Avanendra Singh ◽  
Arpan Nayak ◽  
Pravakar Satapathy ◽  
...  
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Surface Area ◽  
Solid State Reaction ◽  
Average Particle Size ◽  
Cost Effective ◽  
Solid State Reaction Method ◽  
Average Particle ◽  
Reaction Method ◽  
Low Dimensional

In this work, the ZnO-TiO2 mixed phase nanoparticles were prepared by solid state reaction method by using ZnO and TiO2 powder as precursors. The X-ray diffraction pattern shows a dominant phase of Zinc Orthotitanate (Zn2TiO4). The average particle size (58?18 nm) calculated by the analysing FESEM data closely matches with the particle size calculated by Scherrer?s equation. The calculated average particle size is significantly smaller than the previously published results of nanoparticles, prepared by same method. In the Brunauer-Emmett-Teller (BET) study the specific surface area of the nanoparticles was found as 8.78 m2/g which is similar to the surface area reported in this material prepared by mechanochemical method. The method which we report is simpler and cost effective unlike the previous reported.

scholarly journals Electrophysical properties of composites based on epoxy resin and carbon fillers

2021 ◽  
Vol 12 (2) ◽  
pp. 104-111
Author(s):  
O. G. Sirenko ◽  
◽  
O. M. Lisova ◽  
S. M. Makhno ◽  
G. M. Gunya ◽  
...  
Keyword(s):  
Particle Size ◽  
Epoxy Resin ◽  
Size Distribution ◽  
Average Particle Size ◽  
Construction Materials ◽  
Expanded Graphite ◽  
Cost Effective ◽  
Average Particle ◽  
Carbon Filler ◽  
Carbon Fillers

Polymeric construction materials based on epoxy resin, carbon fillers, such as graphene nanoplates (GNP), carbon nanotubes (CNT) and fillers of inorganic nature – perlite, vermiculite, sand with improved electrophysical characteristics have been developed. The electrophysical propertieгs of composites obtained in various ways which differ according to the principle of injecting components have been investigated. GNP were obtained in two ways. Size distribution of GNP obtained by electrochemical method is 50 to 150 nm. The average particle size is up to 100 nm. It occurs that these particles tend to aggregate as it is shown by the method of dynamic light scattering. The GNP obtained by dispersing thermally expanded graphite in water in a rotary homogenizer have a particle size distribution of 400 to 800 nm if very small particles and large aggregates are absent. The second method of obtaining GNP is less energy consuming and requires fewer manufacturing cycles, so it is more cost-effective. Obtaining composites using aqueous suspensions of GNP is environmentally friendly. Due to the hydrophobic properties of its surface the electrical conductivity of the system which uses vermiculite is higher than one of that which uses perlite for composites with CNT and GNP. It has been found that the difference of electrophysical characteristics between two systems which contain the same amount of carbon filler is caused by the nature of the surface of dielectric components – sand. By changing the content of dielectric ingredients can expand the functionality of composites if use them for shielding from electromagnetic fields.

A New Process for Preparing Nanosize Ceramic Powders

1994 ◽  
Vol 351 ◽  
Author(s):  
Yong S. Zhen ◽  
Kenneth E. Hrdina ◽  
Robert J. Remick
Keyword(s):  
Particle Size ◽  
Metal Oxides ◽  
Average Particle Size ◽  
Cost Effective ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Mixed Metal Oxides ◽  
Ceramic Powders ◽  
New Process ◽  
The Cost

ABSTRACTWe have developed a new poly-foam process for the cost effective preparation of ceramic nanoparticles. The process utilizes the chemistry of polyurethane reactions and is proven to be effective for forming nanometer size ceramic powders of a great variety of single metal oxides and mixed metal oxides. In general, ceramic powders can be prepared by this process having a range of average particle size between 3 to 50 nm, with very narrow particle size distribution. They are free of hard agglomerates, are chemically pure and uniform, and are essentially spherical in shape.

scholarly journals Characterisation and Optical Studies of Copper Oxide Nanostructures Doped with Lanthanum Ions

2014 ◽  
Vol 14 (4) ◽  
pp. 49-60 ◽  
Author(s):  
G. Varughese ◽  
V. Rini ◽  
S.P. Suraj ◽  
K.T. Usha
Keyword(s):  
Particle Size ◽  
Copper Oxide ◽  
Average Particle Size ◽  
Band Gap Energy ◽  
Average Particle ◽  
Nano Materials ◽  
Chemical Route ◽  
Direct Band ◽  
Gap States ◽  
La Doped

AbstractCopper Oxide is an extensively studied group II-VI semiconductor with optical properties. It exhibits a wide variety of morphologies in the nano regime that can be grown by tuning the growth habit of the CuO crystal. CuO nano materials with an average particle size of 15-27 nm are synthesized by chemical route. XRD, SEM, FTIR UV-Vis and EDS characterize the samples. The percentage of doping material is confirmed from the EDS spectra. The average crystal size of the prepared CuO: La nanopowder is determined by XRD. The UV absorption spectra revealed the absorption edge at wavelength 389 nm indicating the smaller size of CuO:La nano particle. The optical direct band gap energy of doped CuO nanoparticle is found to be in the range 3.149 eV. The increasing red shift with decreasing particle size suggests that the defects responsible for the intra gap states are primarily surface defect. The La doped CuO is highly effective and can significantly enhance the photo catalytic degradation.

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