The effect of oleic acid on the stability of magnetite ferrofluid

1995 ◽  
Vol 31 (6) ◽  
pp. 4178-4180 ◽  
Author(s):  
M.S. Dababneh ◽  
N.Y. Ayoub
Keyword(s):  
Oleic Acid ◽  
The Stability

scholarly journals Hydrosilylation of Reactive Quantum Dots and Siloxanes for Stable Quantum Dot Films

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 905
Author(s):  
Changmin Lee ◽  
Eunhee Nam ◽  
Woosuk Lee ◽  
Heeyeop Chae
Keyword(s):  
Quantum Dots ◽  
Oleic Acid ◽  
Nucleophilic Addition ◽  
Addition Reaction ◽  
Light Emitting Diode ◽  
Molecular Structures ◽  
One Pot ◽  
Nucleophilic Addition Reaction ◽  
The Stability ◽  
Photo Stability

The reactive acrylate-terminated CdZnSeS/ZnS quantum dots (QDs) were designed and prepared by the effective synthetic route to bond with a siloxane matrix via hydrosilylation. The conventional QD with oleic acid ligands does not have any reactivity, so the QDs were functionalized to assign reactivity for the QDs by the ligand modification of two step reactions. The oleic acid of the QDs was exchanged for hydroxyl-terminated ligands as an intermediate product by one-pot reaction. The hydroxyl-terminated QDs and acrylate-containing isocyanates were combined by nucleophilic addition reaction with forming urethane bonds and terminal acrylate groups. No degradation in quantum yield was observed after ligand exchange, nor following the nucleophilic addition reaction. The modification reactions of ligands were quantitatively controlled and their molecular structures were precisely confirmed by FT-IR and 1H-NMR. The QDs with acrylate ligands were then reacted with hydride-terminated polydimethylsiloxane (H-PDMS) to form a QD-siloxane matrix by thermal curing via hydro-silylation for the first time. The covalent bonding between the QDs and the siloxane matrix led to improvements in the stability against oxygen and moisture. Stability at 85 °C and 85% relative humidity (RH) were both improved by 22% for the QD-connected siloxane QD films compared with the corresponding values for conventional QD-embedded poly(methylmethacrylate) (PMMA) films. The photo-stability of the QD film after 26 h under a blue light-emitting diode (LED) was also improved by 45% in comparison with those of conventional QD-embedded PMMA films.

scholarly journals Stability studies of mefenamic acid Self-Nanoemulsifying Drug Delivery System (SNEEDS) preparation with oleic acid as the oil phase

2020 ◽  
Vol 16 (2) ◽  
pp. 130-143
Author(s):  
Yandi Syukri ◽  
Septiani Eka Cahyani ◽  
Bambang Hernawan Nugroho
Keyword(s):  
Oleic Acid ◽  
Mefenamic Acid ◽  
Tween 80 ◽  
Stability Studies ◽  
Storage Test ◽  
Peg 400 ◽  
Accelerated Storage ◽  
The Stability ◽  
Accelerated Storage Test

Background: Mefenamic acid is a non-steroidal anti-inflammatory drug (NSAID) with low solubility in water. Self-Nanoemulsifying Drug Delivery Systems (SNEDDS) play a role to improve the solubility and bioavailability of mefenamic acid. Objective: This study aimed to determine the stability of mefenamic acid in SNEDDS formulation through various stability studies. Methods: The stability studies conducted consisted of centrifugation test, heating-cooling cycle test, freezethaw cycle test, robustness to dilution, accelerated storage test, and determination of drug content. Results: The centrifugation test, heating-cooling cycle test, and freeze-thaw cycle test showed no phase separation in the samples. The robustness to dilution and accelerated storage test resulted in 2 formulas of mefenamic acid loaded SNEDDS having good stability with 10% oleic acid, 80% tween 80, 10% PEG 400 and 10% oleic acid, 70% tween 80, 20% PEG 400. The determination of drug content in both of these formulations showed 98.20 ± 0.04% and 90.98 ± 0.06%. Conclusion: The SNEDDS formulation of mefenamic acid in this study had good stability. Keywords: SNEDDS, mefenamic acid, stability study, oleic acid

Influence of HLB Parameters of Surfactants on Properties of Magneto-Rheological Fluid

2010 ◽  
Vol 97-101 ◽  
pp. 843-847 ◽  
Author(s):  
Cheng Bin Du ◽  
Wei Qing Chen ◽  
Fa Xue Wan
Keyword(s):  
Magnetic Properties ◽  
Oleic Acid ◽  
Polyethylene Glycol ◽  
Rheological Properties ◽  
Magnetic Particles ◽  
Hydrophilic Lipophilic Balance ◽  
The Stability ◽  
Magneto Rheological

The hydrophilic-lipophilic balance (HLB) parameters of surfactants have a significant effect on properties of surfactants and determine the effects of surfactants. The magneto-rheological fluid (MRF) is prepared by using the two typical HLB parameters of surfactants including Polyethylene Glycol and oleic acid in order to improve the property of MRF. Polyethylene Glycol (PEG) whose HLB parameter is 20 has strong hydrophilic. Oleic acid whose HLB parameter is 1 has strong lipophilic. The results indicate that magnetic properties of magnetic particles and rheological properties of MRF can hardly be changed by adding surfactants. The sedimentary stability of MRF adding lipophilic surfactants is superior to that of MRF adding hydrophilic surfactants, and the stability of MRF adding two surfactants increases significantly.

Esterification of Oleic Acid with Methanol Catalyzed by P-Toluene Sulphonic Acid/MCM-41

2013 ◽  
Vol 634-638 ◽  
pp. 869-872 ◽  
Author(s):  
Li Jing Gao ◽  
Wei Xu ◽  
Guo Min Xiao
Keyword(s):  
Oleic Acid ◽  
Active Catalyst ◽  
Acid Value ◽  
Solution Concentration ◽  
Sulphonic Acid ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Catalyst Amount ◽  
The Stability ◽  
Mcm 41

The p-toluene sulphonic acid (PTSA)/MCM-41 was prepared by impregnation method with self-synthesized MCM-41. The investigation of effects on PTSA solution concentration was investigated and the catalyst prepared with 0.1mol/L PTSA performed best. Oleic acid was chosen as a simulation of high-acid-value oil to esterify with methanol. The experimental results showed that PTSA/MCM-41 was a high active catalyst in esterification. The optimal condition was as following: the reaction temperature was 80°C, the methanol/oleic acid molar ratio was 5:1, the catalyst amount was 5% (wt. /wt.) of the oleic acid, and reaction time was 1h. Under this condition, the oleic acid conversion could reach 94.3%. The stability of the catalyst was very well for the oleic acid conversion can still maintain 92.8% after used four times.

Effect of Surfactant Excess in Non-Polar Ferrofluids Probed by Small-Angle Neutron Scattering

2009 ◽  
Vol 152-153 ◽  
pp. 198-201 ◽  
Author(s):  
V.I. Petrenko ◽  
M.V. Avdeev ◽  
V. L. Aksenov ◽  
L.A. Bulavin ◽  
L. Rosta
Keyword(s):  
Oleic Acid ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Free Acid ◽  
Magnetic Fluids ◽  
Particle Aggregation ◽  
Free Oleic Acid ◽  
The Stability ◽  
Pure Benzene

The microstructure of ferrofluids (magnetite/oleic acid/benzene) with an excess of free oleic acid is investigated by small-angle neutron scattering (SANS). For such excess higher than 25 vol. % a sharp break in the stability of ferrofluids occurs followed by coagulation and precipitation. Below this value the influence of the surfactant excess on the stability of ferrofluids is insignificant; neither particle aggregation nor surfactant agglomeration is observed. The interaction of free acid molecules in the ferrofluids is compared with that in pure benzene solutions. A significant increase in the attraction is observed for acid molecules in the ferrofluids, which is related to the loss of magnetic fluids stability at high excess of acid.

On increase in stability of superhydrophobic oleic acid layers on surface of D16 aluminum alloy

2021 ◽  
pp. 1-8
Author(s):  
A. M. Semiletov ◽  
◽  
A. A. Kudelina ◽  
Yu. I. Kuznetsov ◽  
◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Oleic Acid ◽  
Water Solution ◽  
Salt Spray ◽  
Alloy Surface ◽  
Textured Surface ◽  
Layer By Layer ◽  
Spray Chamber ◽  
Protective Capacity ◽  
The Stability

The possibility of increasing the stability of SHP layers formed from ethanol solutions of oleic acid (OlA) by layer-by-layer modification of the laser-textured surface of the alloy D16 by ethanol solutions of trialkoxysilanes (vinyltrimethoxysilane (VS), octyltriethoxysilane (OTES)) is discussed. It is shown that OTES is more effective than VS in achieving the SHF state of the alloy surface. The protective ability of the coatings was evaluated by polarization measurements in 0,05 M NaCl water solution and corrosion tests in a salt spray chamber. It is shown that the two-stage modification of the alloy surface in solutions of OTES and OlA at Cin = 10 mmol / l, allows one to surpass the protective capacity of individual components, and τcor = 498 h. It is important that the SHP properties of the coating are preserved for 240 hours of testing under salt spray chamber conditions.

Effect of oleic acid on the stability and rheology of nanoaluminium/JP‐10 bi‐phase system

2017 ◽  
Vol 12 (9) ◽  
pp. 675-679 ◽  
Author(s):  
Bing Hong Chen ◽  
Jian Zhong Liu ◽  
Feng Yao ◽  
He Ping Li ◽  
Jun Hu Zhou
Keyword(s):  
Oleic Acid ◽  
Phase System ◽  
The Stability

scholarly journals Effects of Oleic Acid on the Stability of Perovskite CsPbBr3 Quantum Dot Dispersions

2019 ◽  
Vol 48 (4) ◽  
pp. 349-352 ◽  
Author(s):  
Takuma Kosugi ◽  
Yoshiki Iso ◽  
Tetsuhiko Isobe
Keyword(s):  
Oleic Acid ◽  
Quantum Dot ◽  
The Stability

scholarly journals THE INACTIVATION OF THE VIRUS OF EPIDEMIC INFLUENZA BY SOAPS

1940 ◽  
Vol 71 (5) ◽  
pp. 661-681 ◽  
Author(s):  
C. Chester Stock ◽  
Thomas Francis
Keyword(s):  
Fatty Acids ◽  
Influenza Virus ◽  
Oleic Acid ◽  
Chloride Solution ◽  
Calcium Chloride Solution ◽  
Hydrogen Ion ◽  
Ion Concentrations ◽  
Active Virus ◽  
The Stability ◽  
Infectious Property

The capacity of certain fatty acids at pH 7.5 to inactivate the virus of epidemic influenza has been demonstrated. Most effective of these are oleic, linolic, and linolenic acids. Studies were made of such variables as pH, rate of inactivation, and ratios of reactant concentrations, using oleic acid as a prototype of the effective acids. Attempts to recover active virus from inactive mixtures by decrease in pH, dialysis, dilution, or addition of calcium chloride solution to inactivated virus have been unsuccessful. The stability of virus at different hydrogen ion concentrations has been determined. Quantitative comparisons have been made of the immunizing capacity of fully active virus and virus rendered non-infectious by treatment with oleic acid. It was found that while the infectious property of the virus is removed the immunogenic capacity is essentially unaltered. The possible mechanism by which the soaps act upon influenza virus has been discussed.

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