Synthesis of a KNbO3 particle/polymer hybrid from metalorganics

2003 ◽  
Vol 18 (7) ◽  
pp. 1679-1685 ◽  
Author(s):  
Toshinobu Yogo ◽  
Kouichi Banno ◽  
Wataru Sakamoto ◽  
Shin-ichi Hirano
Keyword(s):  
Silicone Oil ◽  
Organic Matrix ◽  
Potassium Niobate ◽  
Polymer Hybrid ◽  
Nanocrystalline Particles ◽  
Hydrolysis Conditions ◽  
Stress Dependent ◽  
Niobium Ethoxide ◽  
Electrorheological Properties ◽  
Controlled Hydrolysis

A nanocrystalline KNbO3 particle/polymer hybrid was synthesized through controlled hydrolysis and polymerization of metalorganics below 100 °C. A KNbO3 precursor was synthesized from potassium ethoxide, niobium ethoxide, and acetoacetoxyethyl methacrylate. The K–Nb alkoxide precursor was hydrolyzed and polymerized yielding KNbO3 particle/polymer hybrid. The organic matrix included nanometer-sized crystalline particles depending upon the hydrolysis conditions. The nanocrystalline particles were identified to be potassium niobate by electron diffraction and energy dispersive x-ray analysis. The suspension of the hybrid in silicone oil revealed a yield stress dependent upon various conditions, such as concentration and applied field. The hybridization was found to have a pronounced effect on the electrorheological properties of the fluid, including the KNbO3 particle/polymer hybrid.

Synthesis and field-responsive properties of SrTiO3 nanoparticle/polymer hybrid

2009 ◽  
Vol 24 (7) ◽  
pp. 2221-2228 ◽  
Author(s):  
Junji Umeda ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Strontium Titanate ◽  
Photoelectron Spectroscopy ◽  
Silicone Oil ◽  
Organic Matrix ◽  
Titanium Isopropoxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polymer Hybrid ◽  
Hydrolysis Conditions ◽  
Stress Dependent

Nanocrystalline strontium titanate (SrTiO3) particle/polymer hybrid was synthesized from metal–organics and 2-(methacryloyloxy)ethyl maleate (MMEM). SrTiO3 precursor was prepared from strontium isopropoxide and titanium isopropoxide in 2-methoxyethanol. Nanocrystalline SrTiO3 particle/poly-MMEM hybrid was formed by hydrolysis followed by reaction with MMEM. The crystallinity of SrTiO3 particles depended on the amount of water for hydrolysis. The nanocrystalline particles were identified to be strontium titanate by x-ray diffraction. Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy showed the presence of the chemical bond between SrTiO3 particles and the organic matrix. The fluid consisting of SrTiO3 particle/poly-MMEM and silicone oil revealed a yield stress dependent on various conditions, such as hydrolysis conditions and applied field. The hybridization was found to have a pronounced effect on the electrorheological properties of the nanoparticle/polymer-based system.

Synthesis of PbTiO3/organic hybrid from metalorganic compounds

1999 ◽  
Vol 14 (8) ◽  
pp. 3275-3280 ◽  
Author(s):  
Toshinobu Yogo ◽  
Hiroyuki Ukai ◽  
Wataru Sakamoto ◽  
Shin-ichi Hirano
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Lead Titanate ◽  
Organic Matrix ◽  
Titanium Isopropoxide ◽  
Resonance Spectroscopy ◽  
X Ray ◽  
Organic Hybrid ◽  
Nanocrystalline Particles ◽  
Hydrolysis Conditions ◽  
Metalorganic Compounds

A nanocrystalline PbTiO3 particle/organic hybrid was synthesized through hydrolysis and polymerization of metalorganic compounds below 100 °C. The PbTiO3 precursor was synthesized from lead methacrylate and titanium isopropoxide. The formation of a Pb–Ti complex alkoxide was confirmed by H and Pb nuclear magnetic resonance spectroscopy. Hydrolyzed Pb–Ti alkoxide was polymerized, yielding the PbTiO3 particles/oligomer hybrid. The organic matrix included nano-sized crystalline particles, depending on the hydrolysis conditions. The nanocrystalline particles were identified to be lead titanate by electron diffraction and energy-dispersive x-ray analysis. The dielectric constant of the nanometer-sized PbTiO3/oligomer hybrid was 5.2 at 10 kHz.

In situ synthesis of nanocrystalline BaTiO3 particle–polymer hybrid

2004 ◽  
Vol 19 (11) ◽  
pp. 3290-3297 ◽  
Author(s):  
Toshinobu Yogo ◽  
Tomoe Yamamoto ◽  
Wataru Sakamoto ◽  
Shin-ichi Hirano
Keyword(s):  
Dielectric Constant ◽  
Electron Diffraction ◽  
Direct Current ◽  
Silicone Oil ◽  
In Situ Synthesis ◽  
Current Field ◽  
Polymer Hybrid ◽  
Nanocrystalline Particles ◽  
Hydrolysis Of

Nanocrystalline BaTiO3 particle–polymer hybrid was synthesized by polymerization and hydrolysis of [2-(methacryloxy)ethoxy]triisopropoxytitanium (MEPT) and barium alkoxide. The precursor for hybrid was synthesized from prepolymerized MEPT and barium alkokide, which was then hydrolyzed to form BaTiO3 particle–polymer hybrids below 100 °C. BaTiO3 particles increased in crystallinity when the amount of water for hydrolysis increased. The nanocrystalline particles were identified to be BaTiO3 by electron diffraction. Nanometer-sized BaTiO3 particle–polymer hybrid was shaped to a film with a dielectric constant of 8.2 at 10 kHz. A suspension consisting of the hybrid and silicone oil responded to a direct-current field, exhibiting a typical electrorheological behavior.

Synthesis of ZnO particle–polymer hybrid from zinc–organics

2004 ◽  
Vol 19 (2) ◽  
pp. 651-656 ◽  
Author(s):  
Toshinobu Yogo ◽  
Tomoko Nakafuku ◽  
Wataru Sakamoto ◽  
Shin-ichi Hirano
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Hybrid Film ◽  
Organic Matrix ◽  
Controlled Polymerization ◽  
Transparent Films ◽  
Polymer Hybrid ◽  
Nanocrystalline Particles ◽  
Nuclear Magnetic Resonance Spectra ◽  
Zno Particles ◽  
Hydrolysis Of

Nanocrystalline ZnO particle–polymer hybrid was synthesized by controlled polymerization and hydrolysis of zinc acrylate (ZA). 13C nuclear magnetic resonance spectra revealed the polymerization of ZA during hydrolysis in the presence of hydrazine at 65 °C for 24 h. Nanocrystalline ZnO particles were dispersed in the organic matrix through the polymerization–hydrolysis reaction of ZA using hydrazine or methylhydrazine. ZnO particles increased in crystallinity with increasing amount of water for hydrolysis in the system using hydrazine. Methylhydrazine was found to yield ZnO with higher crystallinity than that obtained using hydrazine. The nanocrystalline particles were identified to be ZnO by electron diffraction. ZnO particle–polymer hybrid was workable by mild heating into transparent films between silica plates. The absorption edge of the transparent ZnO particle–polymer hybrid film was blue-shifted depending on the size of ZnO particles.

Synthesis of spinel iron oxide nanoparticle/organic hybrid for hyperthermia

2008 ◽  
Vol 23 (12) ◽  
pp. 3415-3424 ◽  
Author(s):  
Koichiro Hayashi ◽  
Toshifumi Shimizu ◽  
Hidefumi Asano ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Photoelectron Spectroscopy ◽  
Iron Oxide Nanoparticle ◽  
Organic Hybrid ◽  
Oxide Nanoparticle ◽  
Hydrolysis Conditions ◽  
Size Controlled ◽  
Controlled Hydrolysis

Size-controlled spinel iron oxide (SIO) nanoparticle/organic hybrid was synthesized in situ from iron (III) allylacetylacetonate (IAA) at around 80 °C. The formation of SIO particles chemically bound with organics was confirmed by infrared and x-ray photoelectron spectroscopy. The sizes of SIO nanoparticles in the hybrids were monodispersed and ranged from 7 to 23 nm under controlled hydrolysis conditions. The hybrid including SIO particles of 7.3 nm was superparamagnetic, whereas those dispersed with particles above 11 nm were ferrimagnetic. The specific absorption rate (SAR) value was dependent upon the magnetic properties of the hybrid at 100 Oe. The SAR was 15.2 W g−1 in a 230 kHz alternating magnetic field and 100 Oe when the crystallite size of SIO particle in the hybrid was 16 nm. The temperatures of agars dispersed with hybrid powders of 5 and 8 mg ml−1 reached the optimum temperature (42 °C) for 17 and 8 min, respectively. The increase in temperature was controlled in terms of the strength of magnetic field. The simulation of heat transfer in the agar phantom model revealed that the suitable temperature distribution for therapy was attained from 15 to 20 min at 230 kHz and 100 Oe.

Electrorheological Properties of Suspensions Based on Polyaniline-montmorillonite Clay Nanocomposite

2002 ◽  
Vol 17 (6) ◽  
pp. 1513-1519 ◽  
Author(s):  
Jun Lu ◽  
Xiaopeng Zhao
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Yield Stress ◽  
Electric Fields ◽  
High Dielectric Constant ◽  
Silicone Oil ◽  
Transmission Electron ◽  
High Dielectric ◽  
Er Fluid ◽  
Electrorheological Properties

It is thought that high-dielectric constant, suitable conductivity, and dielectric loss dominate electrorheological (ER) effects. According to this viewpoint, the polyaniline/montmorillonite nanocomposite (PANI-MMT) particles with high-dielectric constant and suitable conductivity were synthesized by an emulsion intercalation method. The electrorheological properties of the suspensions of PANI-MMT particles in silicone oil have been investigated under direct current electric fields. At room temperature, it was found that the yield stress of PANI-MMT ER fluid was 7.19 kPa in 3 kV/mm, which is much higher than that of pure polyaniline (PANI), that of pure montmorillonite (MMT) as well as that of the mixture of polyaniline with clay (PANI+MMT). In the range of 10–100 °C, the yield stress changed only 6.5% with the variation of temperature. The sedimentation ratio of PANI-MMT ERF was about 98% after 60 days. The structure of PANI-MMT particles was characterized by infrared, x-ray diffraction (XRD), and transmission electron microscopy (TEM) spectrometry, respectively. The XRD spectra show that the inner layer distance of PANI-MMT can be enhanced to 1.52 nm when the PANI was inserted into the interlayer of MMT, whereas it is only 0.96 nm for free MMT. TEM shows that the diameter of PANI-MMT particles is about 100 nm. The dielectric constant of PANI-MMT nanocomposite was increased 5.5 times that of PANI and 2.7 times that of MMT, besides, the conductivity of PANI-MMT particle was increased about 8.5 times that of PANI at 1000 Hz. Meanwhile, the dielectric loss tangent can also be increased about 1.7 times that of PANI. It is apparent that the notable ER effect of PANI-MMT ER fluid was attributed to the prominent dielectric property of the polyaniline-montmorillonite nanocomposite particles.

Synthesis and Characterization of Vanadium Oxide Gels from Alkoxy-Vanadate Precursors

1988 ◽  
Vol 121 ◽  
Author(s):  
C. Sanchez ◽  
M. Nabavi ◽  
F. Taulelle
Keyword(s):  
Vanadium Oxide ◽  
Synthesis And Characterization ◽  
Large Excess ◽  
Vanadium Oxide Gels ◽  
Hydrolysis Conditions ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis ◽  
Alkoxide Precursors ◽  
Inorganic Precursors

ABSTRACTVanadium oxide gels are synthesized through vanadium oxo-alkoxide hydrolysis condensation processes. Different precursors and hydrolysis conditions lead to different sorts of gels. V0(0Amt)3 hydrolyzed with a large excess of water results in red jammy gels with a layered structure. They exhibit electronic and ionic behavior comparable to vanadium pentoxide gels from inorganic precursors. Hydrolysis of VO(OPrn)3 in an alcoholic medium, leads to orange transparent monolithic gels. They have a highly branched polymeric structure. Controlled hydrolysis of vanadium oxo-alkoxide precursors has the further advantage of giving good adherent thin films.

scholarly journals Electrorheological Properties of Suspensions of Polypyrrole Ribbon Particles in Silicone Oil

2011 ◽  
Author(s):  
Shawqi Almajdalawi ◽  
Vladimir Pavlinek ◽  
Qilin Cheng ◽  
Petr Saha ◽  
Miroslav Mrlik ◽  
...  
Keyword(s):  
Silicone Oil ◽  
Electrorheological Properties
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