scholarly journals Aqueous dispersions of epoxy oligomers: Stability and rheological properties

Chemija ◽  
2021 ◽  
Vol 32 (3-4) ◽  
Author(s):  
D. A. Busel ◽  
V. D. Koshevar ◽  
A. Zarkov ◽  
V. G. Shkadrecova ◽  
A. Kareiva
Keyword(s):  
Polyethylene Glycol ◽  
Rheological Properties ◽  
Epoxy Resins ◽  
Glycol Ether ◽  
Ionic Surfactant ◽  
Aqueous Dispersions ◽  
Epoxy Oligomers ◽  
The Stability ◽  
Epoxy Groups

In this study, the stability of the aqueous dispersions of epoxy oligomers was investigated. The following epoxy oligomers with various numbers of epoxy groups were used for the characterization: NPEL 127, NPEL 128, NPEL 134, NPPN 631, EPOXY 520 and DEG-1. A non-ionic surfactant Emulsogen LCN-287 based on alkyl polyethylene glycol ether was used as an emulsifier. The dispersions of epoxy resins were fabricated by changing the content of a non-ionic surfactant (emulsifier) in a range from 2 to 6 wt.%. It was demonstrated that the stability of aqueous emulsions depends not only on the type of resin, but also on the content of the oil phase and the concentration of the emulsifier. The rheological properties of the aqueous dispersions of epoxy oligomers were investigated as well.

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.

The Effect of the Concentration of Non-ionic Surfactant Amphiphilic Molecules on the Structure and Gelation in Aqueous Dispersions

2020 ◽  
Vol 65 (9) ◽  
pp. 1475-1483
Author(s):  
S. A. Alekseeva ◽  
I. V. Baranets ◽  
V. N. Beresnev ◽  
T. A. Nadervel ◽  
A. D. Kryuchkov ◽  
...  
Keyword(s):  
Ionic Surfactant ◽  
Aqueous Dispersions ◽  
Amphiphilic Molecules

scholarly journals Effect of Photoinitiator on Precursory Stability and Curing Depth of Thiol-Ene Clickable Gelatin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1877
Author(s):  
Kai-Hung Yang ◽  
Gabriella Lindberg ◽  
Bram Soliman ◽  
Khoon Lim ◽  
Tim Woodfield ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Visible Light ◽  
Rheological Properties ◽  
Swelling Ratio ◽  
Sodium Persulfate ◽  
Photo Polymerization ◽  
Gelation Kinetics ◽  
The Stability ◽  
Over Time

Recent advances highlight the potential of photopolymerizable allylated gelatin (GelAGE) as a versatile hydrogel with highly tailorable properties. It is, however, unknown how different photoinitiating system affects the stability, gelation kinetics and curing depth of GelAGE. In this study, sol fraction, mass swelling ratio, mechanical properties, rheological properties, and curing depth were evaluated as a function of time with three photo-initiating systems: Irgacure 2959 (Ig2959; 320–500 nm), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP; 320–500 nm), and ruthenium/sodium persulfate (Ru/SPS; 400–500 nm). Results demonstrated that GelAGE precursory solutions mixed with either Ig2959 or LAP remained stable over time while the Ru/SPS system enabled the onset of controllable redox polymerization without irradiation during pre-incubation. Photo-polymerization using the Ru/SPS system was significantly faster (<5 s) compared to both Ig2959 (70 s) and LAP (50 s). Plus, The Ru/SPS system was capable of polymerizing a thick construct (8.88 ± 0.94 mm), while Ig2959 (1.62 ± 0.49 mm) initiated hydrogels displayed poor penetration depth with LAP (7.38 ± 2.13 mm) in between. These results thus support the use of the visible light based Ru/SPS photo-initiator for constructs requiring rapid gelation and a good curing depth while Ig2959 or LAP can be applied for photo-polymerization of GelAGE materials requiring long-term incubation prior to application if UV is not a concern.

scholarly journals Rheological Properties of Aqueous Dispersions of Xanthan Gum Containing Different Chloride Salts Are Impacted by both Sizes and Net Electric Charges of the Cations

2018 ◽  
Vol 13 (2) ◽  
pp. 186-197 ◽  
Author(s):  
Zoila Rosa Nieto Galván ◽  
Lucas de Souza Soares ◽  
Eber Antonio Alves Medeiros ◽  
Nilda de Fátima Ferreira Soares ◽  
Afonso Mota Ramos ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Xanthan Gum ◽  
Aqueous Dispersions ◽  
Chloride Salts

scholarly journals Buffer Additives and Packaging Differentially Influence the Stability of Dyes Commonly Used in Chromovitrectomy

2016 ◽  
Vol 1 (3) ◽  
pp. 1-10
Author(s):  
Begoña Parrado Aliod ◽  
Wilfried Kugler ◽  
Tim Häring
Keyword(s):  
Polyethylene Glycol ◽  
Chemical Stability ◽  
Deuterium Oxide ◽  
Oxidative Degradation ◽  
Bromophenol Blue ◽  
Physiological Range ◽  
Vis Spectroscopy ◽  
The Stability ◽  
Acid Violet ◽  
Dye Solutions

Purpose: This study was performed to investigate the chemical stability of different dyes used in chromovitrectomy and the influence of various product parameters on it. Methods: Buffered dye solutions were prepared containing 1.5 g/L acid violet 17, 0.25 g/L brilliant blue G, 1.3 g/L bromophenol blue, and 1.5 g/L trypan blue, combined with deuterium oxide, polyethylene glycol 3350, and D-mannitol as additives. For accelerated storage testing, samples were incubated for 400 h at 80°C corresponding to 2 years according to the Van ‘t Hoff equation. After different incubation times samples were taken for UV/Vis spectroscopy, pH measurement, and osmometry. Results: Depending on dye, additive, and packaging, different solutions exhibit differences in chemical stability and hence shelf life. Packaging in syringes instead of vials increases dye stability. Additives may negatively influence important parameters, e.g. polyethylene glycol 3350 increases osmolality beyond the physiological range. Notably, acid violet 17 is chemically unstable except in D-mannitol-containing buffer, packed in syringes. However, simultaneously, D-mannitol leads to a pH shift below 7.0. Conclusion: In summary, dye solutions filled in syringes should be preferred to vials to slow down oxidative degradation. Especially acid violet 17 solutions should be used with caution because the addition of D-mannitol may contribute to pH values beyond the physiological range.

scholarly journals Assessment of Fennel Oil Microfluidized Nanoemulsions Stabilization by Advanced Performance Xanthan Gum

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 693
Author(s):  
Rubén Llinares ◽  
Pablo Ramírez ◽  
José Antonio Carmona ◽  
Luis Alfonso Trujillo-Cayado ◽  
José Muñoz
Keyword(s):  
Essential Oil ◽  
Rheological Properties ◽  
Xanthan Gum ◽  
Mechanical Energy ◽  
Physical Stability ◽  
Processing Condition ◽  
Oil In Water ◽  
Mechanical Spectra ◽  
The Stability ◽  
Fennel Oil

In this work, nanoemulsion-based delivery system was developed by encapsulation of fennel essential oil. A response surface methodology was used to study the influence of the processing conditions in order to obtain monomodal nanoemulsions of fennel essential oil using the microchannel homogenization technique. Results showed that it was possible to obtain nanoemulsions with very narrow monomodal distributions that were homogeneous over the whole observation period (three months) when the appropriate mechanical energy was supplied by microfluidization at 14 MPa and 12 passes. Once the optimal processing condition was established, nanoemulsions were formulated with advanced performance xanthan gum, which was used as both viscosity modifier and emulsion stabilizer. As a result, more desirable results with enhanced physical stability and rheological properties were obtained. From the study of mechanical spectra as a function of aging time, the stability of the nanoemulsions weak gels was confirmed. The mechanical spectra as a function of hydrocolloid concentration revealed that the rheological properties are marked by the biopolymer network and could be modulated depending on the amount of added gum. Therefore, this research supports the role of advanced performance xanthan gum as a stabilizer of microfluidized fennel oil-in-water nanoemulsions. In addition, the results of this research could be useful to design and formulate functional oil-in-water nanoemulsions with potential application in the food industry for the delivery of nutraceuticals and antimicrobials.

scholarly journals Modifications of proteins of membrane-cytoskeleton complex and production of reactive oxygen species in erythrocytes cryopreserved with polyethylene glycol

2021 ◽  
Vol 67 (2) ◽  
pp. 44-52
Author(s):  
N.G. Zemlianskykh ◽  
◽  
L.O. Babiychuk ◽  
Keyword(s):  
Reactive Oxygen Species ◽  
Polyethylene Glycol ◽  
Protein Profile ◽  
Control Level ◽  
Reactive Oxygen ◽  
Fold Increase ◽  
Oxygen Species ◽  
Membrane Cytoskeleton ◽  
Extreme Factors ◽  
The Stability

Protein modifications in the membrane-cytoskeleton complex (MCC) of human erythrocytes, as well as changes in the intensity of reactive oxygen species (ROS) production upon cell cryopreservation with polyethylene glycol (PEG) were investigated. The protein profile of ghosts of erythrocytes frozen with PEG has common features with both the control and cells frozen without cryoprotectant. PEG makes it possible to restrict the structural rearrangements of the main MCC proteins under the effect of extreme factors and to restrain the amount of high molecular weight polypeptide complexes induced by the protein-cross-linking reagent diamide at the control level, in contrast to cells frozen without a cryoprotectant. However, changes related to the protein peroxiredoxin 2 in ghosts of erythrocytes cryopreserved with PEG are also attributed to cells frozen without a cryoprotectant that may be associated with the activation of oxidative processes. This is evidenced by a 10-fold increase in ROS formation in erythrocytes frozen under PEG protection. Thus, upon cryopreservation of erythrocytes with PEG, certain disorders in MCC proteins may be associated with increased formation of ROS, which may contribute to the disorganization of the structural components of MCC and disrupt the stability of cryopreserved cells under physiological conditions.

Toughening of epoxy resins by modification with acrylic elastomers containing pendant epoxy groups

1990 ◽  
Vol 26 (2) ◽  
pp. 145-151 ◽  
Author(s):  
Takao Iijima ◽  
Masao Tomoi ◽  
Junichi Yamasaki ◽  
Hiroshi Kakiuchi
Keyword(s):  
Epoxy Resins ◽  
Epoxy Groups

Nanoemulsion with Controlled Rheology under Different Temperature for Effective Removal of Oil-based Drilling Fluid in Offshore Drilling

2021 ◽  
Author(s):  
Renzhou Meng ◽  
Chengwen Wang ◽  
Xiliang Dong ◽  
Chao Xiong
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Rheological Properties ◽  
Drilling Fluid ◽  
Offshore Drilling ◽  
Emulsion Droplets ◽  
Effective Removal ◽  
Engineering Requirement ◽  
Important Means ◽  
The Stability

Abstract Oil-based drilling fluid (OBDF) is an important means for offshore drilling, but it would affect the cementing quality. Nanoemulsions shows potential for OBDF removal, but how to prepare nanoemulsion meeting the engineering requirement is lack of good understanding. Moreover, nanoemulsions usually behave badly under low/high temperature, which would restrict the application. Revealing removal mechanisms of nanoemulsion and improving nanoemulsion stability at different temperature are of great significance. The nanoemulsion could rapidly spread on the wellbore surfaces, cause the adhering OBDF to curl into little droplets, and solubilize the removed OBDF. The removal efficiency can reach more than 98%. Low temperature and higher concentration of dispersed phase both increased the viscosity of nanoemulsions stabilized by surfactants. PEGs can induce the bridging of emulsion droplets at low temperature, leading to significant increase of nanoemulsions viscoelasticity at low temperature (around 5°C). To control the rheological properties of nanoemulsions, a hydrophobic association polymer, HAAP, was proposed. Nanoemulsions containing HAAP does not gel at low temperature (&lt; 15°C). And the viscoelasticity of nanoemulsions increased slightly when the temperature is higher than 70°C because of the thermoassociating behavior of polymer, which can ensure the stability of the nanoemulsions at high temperature. This paper is helpful to establish a generic route for preparing nanoemulsions with controlled rheological properties under different temperature, which is benefit for their applications in offshore.

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