scholarly journals Cyclodextrin-Grafted TiO2 Nanoparticles: Synthesis, Complexation Capacity, and Dispersion in Polymeric Matrices

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 642 ◽  
Author(s):  
Pablo Monreal-Pérez ◽  
José Isasi ◽  
Javier González-Benito ◽  
Dania Olmos ◽  
Gustavo González-Gaitano
Keyword(s):  
Polyethylene Oxide ◽  
Titanium Dioxide Nanoparticles ◽  
High Energy ◽  
Photo Degradation ◽  
Polymeric Matrices ◽  
Tio2 Nps ◽  
The Matrix ◽  
Energy Ball ◽  
Uv Visible ◽  
Modification Of The Surface

The modification of the surface of titanium dioxide nanoparticles (TiO2 NPs) by the incorporation of cyclodextrins (CDs), cyclic oligosaccharides with a hydrophobic cavity, can largely improve the functionality of TiO2 by lodging molecules of interest in the CD to act directly on the surface of the nanoparticles or for further release. With this aim, we have synthesized βCD-modified nanoparticles (βCDTiO2 NPs) by a two-step reaction that involves the incorporation of a spacer and then the linking of the macrocycle, and characterized them by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The capacity of the functionalized structures to trap model compounds (Rhodamine and 1-naphthol) has been compared to that of bare TiO2 NPs by fluorescence and Ultraviolet-visible (UV-visible) spectroscopy. The presence of the CDs on the surface of the TiO2 avoids the photo-degradation of the guest, which is of interest in order to combine the photocatalytic activity of TiO2, one of its most interesting features for practical purposes, with the delivery of compounds susceptible of being photo-degraded. The βCDTiO2 NPs have been dispersed in polymeric matrices of frequently used polymers, polyethylene (LDPE) and polyethylene oxide (PEO), by cryogenic high energy ball milling to produce nanocomposites in the form of films. The surface modification of the nanoparticles favors the homogenization of the filler in the matrix, while the nanoparticles, either in bare or functionalized form, do not seem to alter the crystallization properties of the polymer at least up to a 5% (w/w) load of filler.

Development of Ni/h-BN Self-Lubricating Composite Powder by High-Energy Ball Milling

2016 ◽  
Vol 869 ◽  
pp. 277-282
Author(s):  
Moisés Luiz Parucker ◽  
César Edil da Costa ◽  
Viviane Lilian Soethe
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Solid Lubricants ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Second Phase ◽  
Average Particle ◽  
Composite Powders ◽  
The Matrix ◽  
Energy Ball

Solid lubricants have had good acceptance when used in problem areas where the conventional lubricants cannot be applied: under extreme temperatures, high charges and in chemically reactive environments. In case of materials manufactured by powder metallurgy, particles of solid lubricants powders can be easily incorporated to the matrix volume at the mixing stage. In operation, this kind of material provides a thin layer of lubricant that prevents direct contact between the surfaces. The present study aimed at incorporating particles of second phase lubricant (h-BN) into a matrix of nickel by high-energy ball milling in order to obtain a self-lubricating composite with homogeneous phase distribution of lubricant in the matrix. Mixtures with 10 vol.% of h-BN varying the milling time of 5, 10, 15 and 20 hours and their relationship ball/powder of 20:1 were performed. The effect of milling time on the morphology and microstructure of the powders was studied by X-ray diffraction, SEM and EDS. The composite powders showed reduction in average particle size with increasing milling time and the milling higher than 5 hours resulted in equiaxial particles and the formation of nickel boride.

Investigations on the Structural, Optical and Dielectric Properties of Ball-Milled ZnO–Fe2O3 Nanocomposites

2020 ◽  
Vol 19 (04) ◽  
pp. 1950034
Author(s):  
V. Balachandar ◽  
J. Brijitta ◽  
K. Viswanathan ◽  
R. Sampathkumar
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Ball Milling ◽  
High Energy ◽  
X Ray Diffraction ◽  
Dielectric Constant And Loss ◽  
Energy Ball ◽  
Uv Visible ◽  
Ball Milling Technique ◽  
Xrd Patterns

In this study, ZnO–Fe2O3 nanocomposites were prepared by high-energy ball milling technique and characterized through X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), UV–visible spectroscopy and dielectric spectroscopy. The amount of Fe2O3 in the ZnO–Fe2O3 nanocomposites was varied at the rates of 1[Formula: see text]wt.%, 3[Formula: see text]wt.% and 5[Formula: see text]wt.% in order to investigate its influence on the structural, optical and dielectric properties of the nanocomposites. XRD patterns of nanocomposites revealed no shift in peak positions and hence confirmed the formation of composites after ball milling. Further, it was observed from FESEM analysis that Fe2O3 particles were distributed randomly on the ZnO matrix of the nanocomposites. ZnO–Fe2O3 nanocomposites reveal extended optical absorption in the range of 400–600[Formula: see text]nm from UV studies. The dielectric constant and loss of the nanocomposites decrease exponentially with increase in frequency. The composition and frequency dependences of the dielectric constant, dielectric loss and AC conductivity are explained based on the Maxwell–Wagner effect and Koop’s theory.

Particle Distribution and Mechanical Properties of Nano-SiCP/Al-Cu Composites

2018 ◽  
Vol 941 ◽  
pp. 2060-2065 ◽  
Author(s):  
Shu Sen Wu ◽  
Jian Yu Li ◽  
Ping An ◽  
Shu Lin Lü
Keyword(s):  
Ultrasonic Vibration ◽  
Metal Matrix ◽  
Particle Distribution ◽  
Acoustic Streaming ◽  
High Energy ◽  
Matrix Composites ◽  
Nanosized Particles ◽  
Cu Alloy ◽  
The Matrix ◽  
Energy Ball

Generally it is difficult to disperse nanosized particles uniformly in metal matrix. In this paper nanoSiC particles reinforced Al-5%Cu matrix composites were prepared by molten-metal process, combined with high energy ball-milling and ultrasonic vibration methods. Ultrasonic vibration treatment (UV) has been successfully used to disperse the particles distribution of nanoSiCp particles in the matrix. Big aggregates of particles are eliminated by the effects of cavitation and the acoustic streaming of UV for 1 min. All the particles aggregates are eliminated and the particles are uniformly distributed in the melt after treated by UV for 5 min. The refinement of Al2Cu phase in Al-Cu alloy is more obvious and more uniform distributed with the increase of UV time. The ultimate tensile strength (UTS), yield strength and elongation of the 1wt% nanosized SiCp/Al-5Cu composites treated by UV for 5 min are increased by 37%, 9.5% and 270% respectively, compared with the untreated composites.

The Preparation of Mechanically Alloyed Powders for TEM Examination

1987 ◽  
Vol 115 ◽  
Author(s):  
E. A. Kamenetzky ◽  
M. Wall ◽  
R Castro ◽  
L. E. Tanner
Keyword(s):  
High Energy ◽  
Layered Composite ◽  
The Other ◽  
Outer Diameter ◽  
Ion Milling ◽  
Mechanically Alloyed ◽  
Standard Methods ◽  
The Matrix ◽  
Energy Ball ◽  
Cold Pressed

ABSTRACTTEM specimens of mechanically alloyed elemental Ni and Nb powders are prepared by a new procedure. The alloyed powders are mixed with smaller Al powders and fill an aluminum ring (3mm outer diameter). This composite is cold pressed together with the Al powders taking most of the deformation. The compacted specimen can be mechanically thinned. Electropolishing and ion milling can then proceed by standard methods with special precautions to minimize differential polishing or milling rates.The microstructural aspects of the formation of an amorphous phase by high-energy ball milling these powders have been studied. After 6 h each particle transforms to a heterogeneous layered composite of particles of one element in the matrix of the other. Particle size ranges from 15 nm to 90 nm. Mechanical alloying for 36 h results in the formation of an apparently uniform phase interspersed with a few small (4 nm to 30 nm) elemental crystalline particles. The uniformity of composition and the presence of C, O, and Fe were studied by EDX and EELS.

EFFECT OF MILLING TIME ON MECHANOCHEMICAL SYNTHESIS OF TiO2 NANOPARTICLES

2008 ◽  
Vol 22 (18n19) ◽  
pp. 2955-2961 ◽  
Author(s):  
MARYAM SALARI ◽  
MASIH REZAEE ◽  
S. M. MOUSAVI KOIE ◽  
P. MARASHI ◽  
H. ABOUTALEBI
Keyword(s):  
Milling Time ◽  
Titanium Dioxide Nanoparticles ◽  
Milled Powder ◽  
High Energy ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Starting Mixture ◽  
Annealed Powder ◽  
Energy Ball ◽  
Titanyl Sulphate

Titanium dioxide nanoparticles have great potential for use in photocatalytic applications, cosmetics, white pigments and so on. In this paper, the effect of milling time on particle size, morphology and phase composition of TiO 2 nanoparticles, prepared by mechanochemical method, was investigated by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). TiO 2 nanoparticles were prepared by the use of high energy ball milling of titanyl sulphate ( TiOSO 4) and NaCl powders as the starting mixture in different milling durations. The milled powder was annealed at 700°C for 30 min. The NaCl powder, used as the diluent phase, was removed by washing the annealed powder with distilled water. It was found that with increasing milling time, decrease in the size of equiaxed spherical particles and increase in temperature of anatase to rutile transformation ( A → R ) can be observed.

Spinodal Decomposition in Off-stoichiometric Zr0.5Hf0.5Co1-yIrySb1-zSnz half-Heusler Phases

2010 ◽  
Vol 1267 ◽  
Author(s):  
Nathan J. Takas ◽  
Dinesh Misra ◽  
Heike Gabrisch ◽  
Pierre F. P. Poudeu
Keyword(s):  
Thermal Conductivity ◽  
Spinodal Decomposition ◽  
Lattice Thermal Conductivity ◽  
Large Fraction ◽  
High Energy ◽  
Metallic Phase ◽  
Inclusion Phase ◽  
The Matrix ◽  
Energy Ball

AbstractThe formation of nanostructures within the matrix of half-Heusler thermoelectric materials can be produced by spinodal decomposition of off-stoichiometric compositions. CoSb is insoluble at high temperatures in Zr0.5Hf0.5Co1-yIrySb1-zSnz half-Heusler phases. This phase can be solubilized into the half-Heusler matrix by the use of high energy ball milling at room temperature as the synthetic method of choice. The metastable half-Heusler material decomposes in-situ while hot-pressing the powder sample into a compact pellet. Despite the fact that the thermal conductivity of the inclusion material, CoSb, is very large, (>35W/m•K), we observed reduction in the lattice thermal conductivity of the composite material. Furthermore, the electrical resistivity of the specimen was also reduced due to the metallic nature of the CoSb inclusion phase. Addition of a large fraction of the metallic inclusion leads to a percolation network of the metallic phase, thus reducing the Seebeck coefficient of the composites. Electron microscopy is carried out in order to examine boundaries between the two. Changes in the thermoelectric properties of Zr0.5Hf0.5Co1-yIrySb1-zSnz half-Heusler matrix with increasing mass percent of CoSb inclusion will be discussed.

Preparation and Squeeze Casting of Nano-SiCP/A356 Composite Assisted with Ultrasonic Vibration Process

2016 ◽  
Vol 879 ◽  
pp. 1188-1193 ◽  
Author(s):  
Shu Lin Lü ◽  
Pan Xiao ◽  
Shu Sen Wu ◽  
Xiao Gang Fang
Keyword(s):  
Ultrasonic Vibration ◽  
Squeeze Casting ◽  
A356 Alloy ◽  
High Energy ◽  
Metal Matrix Nanocomposites ◽  
Vibration Process ◽  
The Matrix ◽  
Energy Ball ◽  
Composite Granules ◽  
Matrix Nanocomposites

Metal matrix nanocomposites (MMNCs) have excited great interest in recent years, due to their very good properties. In this work, an efficient process by combining high-energy ball milling (HBM) with ultrasonic vibration (UV) was employed to prepare MMNCs. The composite granules containing nanoSiCP were produced by milling the nanoSiC and Al powders, and then were remelted in the matrix melt and treated by UV to prepare MMNCs. The MMNCs were finally formed by squeeze casting. The results indicate that globular nanoSiCP/Al compound granules with diameters between 1.5-2mm are obtained by dry HBM, and the nanoSiC particles are uniformly distributed in the granules. After remelting, nanoSiC particles in compound granules release in the matrix melt and are uniformly dispersed by UV within 2min. In MMNCs, nanoSiC particles concentrate mainly around eutectic phases, but no agglomeration is observed. The tensile strength of the MMNCs with 1wt.% nanoSiCP is increased by 19%, compared to the matrix A356 alloy.

Preparation and Photocatalytic Properties of Iron Titanate Compounds

2014 ◽  
Vol 937 ◽  
pp. 136-140
Author(s):  
Xue Fei Lei ◽  
Xiang Xin Xue ◽  
He Yang
Keyword(s):  
Emission Spectra ◽  
Light Response ◽  
High Energy ◽  
X Ray Diffraction ◽  
Iron Titanate ◽  
Surface Hydroxyls ◽  
Milling Method ◽  
Energy Ball ◽  
Uv Visible ◽  
And Performance

Iron titanate photocatalysts were synthesized by the high-energy ball milling method with titanium ore as the starting material. X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), thermal gravity and differential thermal analysis (TG-DTA), UV-visible diffuse reflectance absorption spectra (UV-Vis), photoluminescence emission spectra (PL) and photocatalytic degradation measurement were conducted to characterize the structure, surface status, UV-visible light response and performance of the obtained sample. After low temperature calcination (above 400 oC), the photocatalytic activity of iron titanate catalyst decreased gradually, which was mainly due to the decrease of surface hydroxyls and reactant adsorption capability.

Strengthening in CNT-Al Composites Produced by High-Energy Ball Milling

2011 ◽  
Vol 236-238 ◽  
pp. 2336-2339 ◽  
Author(s):  
Xiao Fei Wang ◽  
Xiao Lan Cai
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Matrix Composites ◽  
The Matrix ◽  
Energy Ball ◽  
Al Matrix Composites ◽  
Ball Milling Time

In this paper, carbon nanotubes (CNT)-reinforced aluminum (Al) matrix composites were fabricated by High-Energy Ball Milling, the objective was to investigate the evolvement of particle size, density and hardness of CNT-Al composites with increasing wt% CNT, and analyzed the micrographs of mixture powders at different milling time. The results showed that the addition of CNT can play a role of grinding aid to refine grain, improve the hardness and decrease the density, and CNT can be homogeneous dispersed in the matrix with increasing ball-milling time, it also showed that too much CNT was no help on hardness, this attributed to clustering of CNT, the proper addition of CNT was 2wt%, and the mixture powders could reached a state of equilibrium between fracturing and cold-welding at 75min.

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