scholarly journals A Perturbation Analysis Approach for Studying the Effect of Swelling Kinetics on Instabilities in Hydrogel Plates

2021 ◽  
Vol 88 (5) ◽  
Author(s):  
Arne Ilseng ◽  
Bjørn H. Skallerud ◽  
Bjørn T. Stokke ◽  
Victorien Prot
Keyword(s):  
Perturbation Analysis ◽  
Material Properties ◽  
Stability Limit ◽  
Swelling Kinetics ◽  
Swelling Ratio ◽  
Analysis Framework ◽  
Graded Material ◽  
Kinetic Effects ◽  
The Stability ◽  
Kinetics Of

Abstract The onset of surface instability during diffusion-driven swelling of hydrogels depends on the kinetics of the swelling process. Here, we outline a perturbation analysis framework using a finite difference approach for calculating the stability limit of swelling hydrogel plates with graded material properties accounting for kinetic effects. The framework is implemented as a Python routine which is made freely available. Results obtained for bilayered hydrogel plates illustrate that the onset of instability occurs earlier in time and at a lower global swelling ratio when kinetics is accounted for compared to the homogeneous swelling case. This work presents an accessible calculation tool for stability analysis of swelling gels, providing input for the design of novel hydrogel systems.

Curing and swelling kinetics of new magnetorheological elastomer based on natural rubber/waste natural rubber gloves composites

2018 ◽  
Vol 51 (7-8) ◽  
pp. 583-602
Author(s):  
Nabil Hayeemasae ◽  
Hanafi Ismail
Keyword(s):  
Natural Rubber ◽  
Material Properties ◽  
Swelling Kinetics ◽  
Curing Process ◽  
Magnetorheological Elastomer ◽  
Rubber Composites ◽  
Rubber Waste ◽  
New Type ◽  
Kinetics Of ◽  
Single Filler

This article proposes a new type of magnetorheological elastomer (MRE) based on natural rubber (NR) and waste natural rubber gloves (wNRg) blends. The material properties of the MRE samples were investigated with specific focus on the curing and swelling kinetics. Two different series were prepared; the first used carbonyl iron (CI) as the single filler in the MRE, whereas the second hybridized CI with carbon black (CB) to prepare an MRE resistant to solvents. The results show that most properties depend strongly on the nature of both fillers. The higher thermal conductivity of the CI caused a substantial decrease in both the scorch and curing times and the activation energy in the curing process. Based on the diffusion study, a higher volume of fillers in the rubber composites resulted in a greater area of blockage and restricted the penetration of the solvent tested throughout the composites, irrespective of whether CI alone or in combination with CB was used in the composites.

EFFECT OF PHBV CONTENT ON THE TRANSPARENCY AND SWELLING BEHAVIOR OF POLYMER/HECTORITE NANOCOMPOSITE HYDROGEL

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1365-1370 ◽  
Author(s):  
QINGSONG ZHANG ◽  
YIPING ZHAO ◽  
LI CHEN
Keyword(s):  
Gravimetric Method ◽  
Polymer Chains ◽  
Swelling Kinetics ◽  
Swelling Ratio ◽  
Nanocomposite Hydrogels ◽  
Cross Linker ◽  
Kinetics Of ◽  
Inorganic Network ◽  
Pure Poly

As a kind of novel biopolymer material with good biodegradability and biocompatibility, poly(β-hydroxybutyrate-co-valerate)(PHBV) was introduced into organic/inorganic network structure of nanocomposite hydrogels prepared by in-situ free-radical polymerization based on monomer N-isopropylacrylamide(NIPAM) and physical cross-linker hectorite. As viewed from appearance of the hydrogels, obvious change occurred from transparent to white with the increase of PHBV content, which reflects the structural shift from homogeneity to inhomogeneity. The swelling ratio and swelling kinetics of thermo-sensitive poly( NIPAM / PHBV /Hectorite) hydrogels with different PHBV content was investigated by gravimetric method. It was found that the incorporation of PHBV decreases the swelling ratio of pure poly( NIPAM /Hectorite) hydrogels on account of hydrophobicity of PHBV . Furthermore, in the case of swelling kinetics, the result of linear regression shows that relaxation of polymer chains of the hydrogels controls the swelling process.

KINETICS AND THERMAL STABILITY OF Nd55Al20Fe25 BULK METALLIC GLASS

2006 ◽  
Vol 20 (05) ◽  
pp. 225-232 ◽  
Author(s):  
L. XIA ◽  
Y. D. DONG
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Stability Limit ◽  
Supercooled Liquid ◽  
Kauzmann Temperature ◽  
The Stability ◽  
Kinetics Of ◽  
Thermal Stability Of

In this work, we studied the thermal stability and kinetics of Nd 55 Al 20 Fe 25 bulk metallic glass (BMG) with distinct glass transition and multistage crystallizations. The kinetics of glass transition and crystallizations were investigated using the Kissinger method and the ideal glass transition temperature of the alloy was obtained via Lasoka's equation. The thermal stability of the BMG was investigated by means of continuous transformation diagrams obtained from the extension of Kissinger analysis. It is suggested that the stability limit of the supercooled liquid, i.e. Kauzmann temperature, could also be regarded as the long-term stability criteria of the BMG.

Effect of Salinity and Temperature on Swelling Behavior of Nano/Micro Polymer Particle

2013 ◽  
Vol 448-453 ◽  
pp. 3993-3997
Author(s):  
Yu Lou ◽  
Wei Yao Zhu ◽  
Xue Ling Zhang ◽  
Yun Qian Long
Keyword(s):  
Oil Recovery ◽  
Polymer Particle ◽  
Swelling Behavior ◽  
Swelling Kinetics ◽  
Swelling Ratio ◽  
Polymer Particles ◽  
Equilibrium Swelling ◽  
Swelling Characteristics ◽  
Equilibrium Swelling Ratio ◽  
Kinetics Of

Nano/micro polymer particles of acrylamide (AM), acrylic acid (AA), methyl methacrylate (MMA) are used to enhance oil recovery. Swelling kinetics of nano/micro polymer particles were investigated through experimental analysis and statistical analysis. The effect of salinity and temperature on swelling behavior over time is studied experimentally. The swelling kinetics of nano/micro polymer particle was described by second order kinetics. Equilibrium swelling ratio and swelling rate were obtained through nonlinear regression. The quantitative relationships between equilibrium swelling ratio and salinity, temperature were presented. Results show that the swelling ratio increases with increasing temperature or decreasing salt concentration. The study provides a direct perspective of swelling characteristics of nano/micro polymer particles for oil recovery enhancement.

Theory of Frictional Vibration in Wet Clutches Considering Poroelastic Properties of Paper-Based Facing

1996 ◽  
Vol 118 (3) ◽  
pp. 520-526 ◽  
Author(s):  
Y. Hattori ◽  
T. Kato
Keyword(s):  
Material Properties ◽  
Stability Limit ◽  
Friction Material ◽  
Sliding Velocity ◽  
Vibration Model ◽  
Lubricant Flow ◽  
Coefficient Versus ◽  
The Stability ◽  
Frictional Vibrations ◽  
Frictional Vibration

This paper presents a new theory on frictional vibrations of paper-based friction material considering the interaction between its deformation and the consequent lubricant flow inside it. A frictional vibration model is proposed, in which a poroelastic body saturated by a viscous liquid is introduced, and then a stability criterion is derived on the assumption that vibrations in two directions, tangential and normal, are coupled. Compared with the experiment, it is confirmed that the proposed criterion can predict the stability limit more accurately than the conventional one, which does not take the deformation of the friction material into account and depends only on the slope of friction coefficient versus sliding velocity. Based on the present criterion, influences of material properties on the stability to frictional vibrations are discussed.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

scholarly journals Polyelectrolyte Gels: A Unique Class of Soft Materials

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 102
Author(s):  
Ferenc Horkay
Keyword(s):  
Exchange Process ◽  
Interaction Strength ◽  
Soft Materials ◽  
Industrial Applications ◽  
Future Research ◽  
Swelling Kinetics ◽  
Polyelectrolyte Gels ◽  
Ion Exchange Process ◽  
Counter Ions ◽  
Kinetics Of

The objective of this article is to introduce the readers to the field of polyelectrolyte gels. These materials are common in living systems and have great importance in many biomedical and industrial applications. In the first part of this paper, we briefly review some characteristic properties of polymer gels with an emphasis on the unique features of this type of soft material. Unsolved problems and possible future research directions are highlighted. In the second part, we focus on the typical behavior of polyelectrolyte gels. Many biological materials (e.g., tissues) are charged (mainly anionic) polyelectrolyte gels. Examples are shown to illustrate the effect of counter-ions on the osmotic swelling behavior and the kinetics of the swelling of model polyelectrolyte gels. These systems exhibit a volume transition as the concentration of higher valence counter-ions is gradually increased in the equilibrium bath. A hierarchy is established in the interaction strength between the cations and charged polymer molecules according to the chemical group to which the ions belong. The swelling kinetics of sodium polyacrylate hydrogels is investigated in NaCl solutions and in solutions containing both NaCl and CaCl2. In the presence of higher valence counter-ions, the swelling/shrinking behavior of these gels is governed by the diffusion of free ions in the swollen network, the ion exchange process and the coexistence of swollen and collapsed states.

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.

Modeling of sorption kinetics of U(VI) micro-quantities nanostructured materials with anatase mesoporous structures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Veniamin Zheleznov ◽  
Aleksey Golikov ◽  
Tatiana Sokolnitskaya ◽  
Sergey Ivannikov
Keyword(s):  
Nanostructured Materials ◽  
Sorption Kinetics ◽  
Uranyl Ion ◽  
Competitive Sorption ◽  
Hydroxyl Groups ◽  
Complex Ions ◽  
The Stability ◽  
Kinetics Of ◽  
Mesoporous Structures ◽  
Ionic Forms

Abstract The sorption kinetics of uranyl ions micro-quantities from fluoride solutions by nanostructured materials with anatase mesoporous structures has been studied. Using the model of competitive sorption of ions and positively charged complexes of uranyl ion on deprotonated hydroxyl groups of an anatase, kinetic curves of changes in the ratio of ionic forms of uranium in solution were calculated. Modeling was carried out under the assumption of a two-stage mechanism of uranium complex ions sorption. The modeling considered the influence of the uranyl ion carbonate complexes formation. The shift in equilibrium among ionic forms of uranyl correlates with the stability of the complexes in solution.

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