Production, deformation and magnetorheological characteristics of the alginate/chitosan hydrogel magnetic microspheres

2021 ◽  
pp. 1045389X2110572
Author(s):  
Yu Fu ◽  
Zhenshuai Wan ◽  
Ye Tian ◽  
Zhihua Zhao ◽  
Gang Zhao
Keyword(s):  
Deionized Water ◽  
Dispersion Stability ◽  
Magnetic Microspheres ◽  
Network Structures ◽  
Chitosan Hydrogel ◽  
New Thought ◽  
Double Network ◽  
Mr Fluids ◽  
First Time ◽  
Mr Characteristics

To improve dispersion stability and magnetorheological (MR) characteristics of carbonyl iron (CI) particles, we proposed novel hydrogel magnetic microspheres (MPs) dual-coated with alginate (AL) and chitosan (CTS) for the first time. The double-network structures formed by biological crosslinking and chelation reactions are capable to enhance its own structural stability and mechanical properties. The structural characterization, MR properties, and dispersion stability for different MPs were investigated. Additionally, the swelling behaviors were studied by swelling the dried MPs in the deionized water and sodium chloride solution, respectively. The results showed that the AL/CTS hydrogel core/shell MPs displayed the advantages of simple manufacturing, superior MR properties and deformability compared to pure micron-sized CI particles, indicating the improved dispersion stability of the MR fluids compared to that of the pure CI particles-based MR fluids. The introduction of double network structures with natural biopolymers will provide a new thought for the development of MR materials.

scholarly journals Radiation-initiated high strength chitosan/lithium sulfonate double network hydrogel/aerogel with porosity and stability for efficient CO2 capture

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20486-20497
Author(s):  
Zhiyan Liu ◽  
Rui Ma ◽  
Wenjie Du ◽  
Gang Yang ◽  
Tao Chen
Keyword(s):  
Aqueous Solution ◽  
High Strength ◽  
Beam Radiation ◽  
Chitosan Hydrogel ◽  
Double Network ◽  
Electron Beam Radiation ◽  
Freeze Dried ◽  
Urea Aqueous Solution ◽  
Capture Capacity

Chitosan hydrogel is regenerated from alkali/urea aqueous solution and the lithium sulfonate second network is introduced by electron beam radiation-initiated in situ free radical polymerization. The freeze-dried aerogel has CO2 capture capacity.

Corrosion Testing of Armour Wire in Simulated Annulus Environments of Flexible Pipelines: An Update

2003 ◽  
Author(s):  
Richard Clements ◽  
Andrew D. Ethridge
Keyword(s):  
Deionized Water ◽  
Small Scale ◽  
General Corrosion ◽  
Flexible Pipe ◽  
Scale Test ◽  
Condensed Water ◽  
Test Cells ◽  
Sour Service ◽  
First Time ◽  
Permeation Models

This paper describes further investigations, utilising small scale test cells, into the general corrosion which can occur on wires within the inherent annulus space in a flexible pipe, particularly, and for the first time, in a sour service (H2S containing) environment. The work enhances data presented previously in 2002. Tests have been performed in cells specifically designed to simulate, as closely as possible, the environment and confines of a flexible pipe annulus, using solutions of both deionized water and seawater (to represent seawater flooding and condensed water). The systems were saturated with CO2 and H2S to simulate permeation of gases through the polymer pressure sheath (as predicted by validated permeation models). Weight loss measurements were undertaken in order to quantify the corrosion rate in these simulated annulus environments and metallography was undertaken to characterise the corrosion and check for HIC/SOHIC.

Magnetorheological Characterization of Polymer-Iron Composite Suspensions

2004 ◽  
Vol 449-452 ◽  
pp. 1201-1204 ◽  
Author(s):  
Min Seong Cho ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetic Field ◽  
Parallel Plate ◽  
Suspension Polymerization ◽  
Measuring System ◽  
Composite Particles ◽  
Dispersed Phase ◽  
Mr Fluids ◽  
Polymerization Method ◽  
Mr Characteristics

Composite particles (CIPMMA) of carbonyl iron (CI) and poly (methyl methacrylate) (PMMA) were prepared by a suspension polymerization method using CI dispersions in MMA monomer, and these were adopted as dispersed phase of magnetorheological (MR) fluids. The CIPMMA can resolve several problems of MR fluids having CI alone such as severe sedimentation and poor dispersion stability. Flow and viscelastic properties of the MR fluids were analyzed via a rotational rheometer equipped with a magnetic field supplier using measuring system of a parallel plate. The MR characteristics like yield stress were affected by the CI contents in the composite particles.

scholarly journals Effects of Crosslinking Methods on Network Structure and Enzymatic Degradation of Methacrylate-Functionalized Chitosan Hydrogel

2018 ◽  
Author(s):  
Juhong Ahn ◽  
Jungju Ryu ◽  
Kwangho Song ◽  
Jungwook Kim
Keyword(s):  
Biomedical Applications ◽  
Enzymatic Degradation ◽  
Network Structures ◽  
Porous Network ◽  
Chitosan Hydrogel ◽  
Shear Moduli ◽  
Network Heterogeneity ◽  
X Ray Scattering ◽  
Degradation Behaviors ◽  
Chitosan Hydrogels

Polysaccharides, such as hyaluronic acid, alginate, or chitosan, can be modified by addition of reactive functional groups to enable chemical crosslinking. Here, we studied how different methods of crosslinking methacrylate-functionalized chitosan affected the network structures of the resulting hydrogels. We then investigated how the porous network structures in turn influenced stiffness, macromolecular diffusion through the pores, and enzymatic degradation. All these properties are relevant for utilization of the chemically crosslinked hydrogels in biomedical applications, including tissue engineering and delivery of therapeutic agents. We made chitosan hydrogels using four crosslinking methods, which differ by type and by reaction kinetics. We found that four chitosan hydrogels having identical polymer fractions at an equilibrium swelling exhibited marked differences in their shear moduli, rate of dextran diffusion, and especially their enzymatic degradation behaviors. We inferred that these differences originated in variations among network structures, which were characterized by the formation of chain bundles and associated network heterogeneity as determined by small-angle X-ray scattering analysis.

scholarly journals Bidisperse Magnetic Particles Coated with Gelatin and Graphite Oxide: Magnetorheology, Dispersion Stability, and the Nanoparticle-Enhancing Effect

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 714 ◽  
Author(s):  
Yu Fu ◽  
Jianjun Yao ◽  
Honghao Zhao ◽  
Gang Zhao ◽  
Zhenshuai Wan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Graphite Oxide ◽  
Self Assembly ◽  
Carbonyl Iron ◽  
Magnetic Particles ◽  
Dispersion Stability ◽  
Functional Coating ◽  
Enhancing Effect ◽  
Mr Fluids

The magnetorheology and dispersion stability of bidisperse magnetic particles (BMP)-based magnetorheological (MR) fluids were improved by applying a novel functional coating composed of gelatin and graphite oxide (GO) to the surfaces of the micron-sized carbonyl iron (CI) and nanoparticles Fe3O4. Gelatin acted as a grafting agent to reduce the aggregation and sedimentation of CI particles and prevent nanoparticles Fe3O4 from oxidation. In addition, a dense GO network on the surface of gelatin-coated BMP was synthesized by self-assembly to possess a better MR performance and redispersibility. The rheological properties of MR fluids containing dual-coated BMP were measured by a rotational rheometer under the presence of magnetic field and their dispersion stability was examined through sedimentation tests. The results showed that CI@Fe3O4@Gelatin@GO (CI@Fe3O4@G@GO) particles possessed enhanced MR properties and dispersion stability. In addition, the nanoparticle-enhancing effects on the dispersion stability of BMP-based MR fluids were investigated using Monte Carlo simulations.

PEG-α-CD/AM/liposome @amoxicillin double network hydrogel wound dressing—Multiple barriers for long-term drug release

2021 ◽  
pp. 088532822199194
Author(s):  
Shan Wang ◽  
Zhicun Wang ◽  
Cheng Xu ◽  
Lin Cui ◽  
Guihua Meng ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Drug Release ◽  
Wound Infection ◽  
Wound Dressing ◽  
Cytotoxicity Test ◽  
Sustained Drug Release ◽  
New Thought ◽  
Double Network ◽  
Antibiotic Drug ◽  
Release Assay

Wound infection and poor wound healing are the major challenges of wound treatment. Antibiotic drug treatment is the effective way to inhibit wound infection. It is necessary to achieve sustained release of antibiotics to get a longer treatment for wound infection. The double network hydrogels based on liposome, polyethylene glycol (PEG), α- cyclodextrin ( α-CD) and acrylamide (AM) were developed, in which liposome acts as amoxicillin repository. Because the drug would release from the multiple barriers including two cavities of liposome and α-CD, as well as polyethylene glycol - α- cyclodextrin/acrylamide (PEG-CD/AM) double network, the PEG- α-CD/AM/liposome @amoxicillin double network hydrogels could achieve sustained drug release. The drug release assay showed that the dressing could release amoxicillin continuously until 12 days, than that of 8th day for single-network hydrogel releasing. The antibacterial ratio of the hydrogel could reach above 80%. What’s more, the hydrogels present adjustable mechanical strength by changing the ratio of the components. The swelling ratio proved that the hydrogel had potential ability to absorb wound exudates. The cytotoxicity test of the hydrogels demonstrated excellent biocompatibility. These results indicated that this study can provide a new thought for antibacterial wound dressing and has a broad application prospect.

scholarly journals Enhanced Magnetorheological Performance of Carbonyl Iron Suspension Added With Barium Ferrite Nanoparticle

2021 ◽  
Vol 8 ◽  
Author(s):  
Hyo Seon Jang ◽  
Qi Lu ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Barium Ferrite ◽  
Flow Behavior ◽  
Vibrating Sample Magnetometry ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Ferrite Nanoparticle ◽  
The Magnetic Field ◽  
Mr Characteristics

Hard-magnetic barium ferrite (BF) nanoparticles with a hexagonal plate-like structure were used as an additive to a carbonyl iron (CI) microparticle-based magnetorheological (MR) fluid. The morphology of the pristine CI and CI/BF mixture particles was examined by scanning electron microscopy. The saturation magnetization and coercivity values of each particle were measured in the powder state by vibrating sample magnetometry. The MR characteristics of the CI/BF MR fluid measured using a rotation rheometer under a range of magnetic field strengths were compared with those of the CI-based MR fluid. The flow behavior of both MR fluids was fitted using a Herschel–Bulkley model, and their stress relaxation phenomenon was examined using the Schwarzl equation. The MR fluid with the BF additive showed higher dynamic and elastic yield stresses than the MR fluid without the BF additive as the magnetic field strength increased. Furthermore, the BF nanoparticles embedded in the space between the CI microparticles improved the dispersion stability and the MR performance of the MR fluid.

scholarly journals Effects of Crosslinking Methods on Network Structure and Enzymatic Degradation of Methacrylate-Functionalized Chitosan Hydrogel

2018 ◽  
Author(s):  
Juhong Ahn ◽  
Jungju Ryu ◽  
Kwangho Song ◽  
Jungwook Kim
Keyword(s):  
Biomedical Applications ◽  
Enzymatic Degradation ◽  
Network Structures ◽  
Porous Network ◽  
Chitosan Hydrogel ◽  
Shear Moduli ◽  
Network Heterogeneity ◽  
X Ray Scattering ◽  
Degradation Behaviors ◽  
Chitosan Hydrogels

Polysaccharides, such as hyaluronic acid, alginate, or chitosan, can be modified by addition of reactive functional groups to enable chemical crosslinking. Here, we studied how different methods of crosslinking methacrylate-functionalized chitosan affected the network structures of the resulting hydrogels. We then investigated how the porous network structures in turn influenced stiffness, macromolecular diffusion through the pores, and enzymatic degradation. All these properties are relevant for utilization of the chemically crosslinked hydrogels in biomedical applications, including tissue engineering and delivery of therapeutic agents. We made chitosan hydrogels using four crosslinking methods, which differ by type and by reaction kinetics. We found that four chitosan hydrogels having identical polymer fractions at an equilibrium swelling exhibited marked differences in their shear moduli, rate of dextran diffusion, and especially their enzymatic degradation behaviors. We inferred that these differences originated in variations among network structures, which were characterized by the formation of chain bundles and associated network heterogeneity as determined by small-angle X-ray scattering analysis.

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