scholarly journals Affordable Magnetic Hydrogels Prepared from Biocompatible and Biodegradable Sources

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1693
Author(s):  
Raluca Ioana Baron ◽  
Gabriela Biliuta ◽  
Vlad Socoliuc ◽  
Sergiu Coseri
Keyword(s):  
Magnetic Particles ◽  
Magnetic Fluids ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Potential Applications ◽  
Pva Solutions ◽  
Superparamagnetic Properties

Magnetic hydrogels composed of poly(vinyl alcohol) (PVA)/water-soluble tricarboxy cellulose (CO)/magnetic fluids (MFs) have been prepared by a freeze–thaw cycle technique. The system designed here combines the renewability and biocompatibility aspects of PVA and CO, as well as the magnetic properties of MFs, thereby offering special properties to the final product with potential applications in medicine. In the first step, the water-soluble CO is synthesized using a one-shot oxidation procedure and then the aqueous solutions of CO are mixed with PVA solutions and magnetic fluids in the absence of any additional cross-linking agent. The magnetic hydrogels were thoroughly investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), magnetometry (VSM), and thermogravimetric analysis. The morphological results show an excellent distribution of magnetic particles and CO inside the PVA matrix. The VSM results show that the magnetic hydrogels possess superparamagnetic properties.

The Effect of Polymerization Mode on the POSS Hybrid PVA Hydrogels

2014 ◽  
Vol 1044-1045 ◽  
pp. 137-140
Author(s):  
Yi Chen ◽  
Wen Yong Liu ◽  
Guang Sheng Zeng ◽  
Jun Hong Yang
Keyword(s):  
Freezing Temperature ◽  
Water Soluble ◽  
Hybrid Nanocomposite ◽  
Elongation At Break ◽  
Cycle Times ◽  
Freeze Thaw ◽  
Nanocomposite Hydrogels ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Lower Temperature

A novel POSS hybrid nanocomposite hydrogels was synthesized by introducing water-soluble Oa-POSS into the PVA hydrogels by freeze-draw mode. The freezing temperature and freeze-thaw cycle times affected the mechanical properties of gels. When polymerizing at lower temperature, the tensile strength and modulus increases and the elongation at break decreases obviously. Meantime, with the increase of freeze-thaw cycle times, the strength, modulus and elongation at break all improved gradually.

A Preliminary Research on Alkali-Activated Slag Concrete as Tunnel Lining in Severe Frigid Regions

2013 ◽  
Vol 668 ◽  
pp. 65-69 ◽  
Author(s):  
Heng Shu
Keyword(s):  
Frost Damage ◽  
Sem Analysis ◽  
Tunnel Lining ◽  
X Ray Diffraction ◽  
Alkali Activated Slag ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Activated Slag ◽  
Alkali Activated

The main structure materials of tunnel lining are concrete and steel, and the concrete frost damage is a typical degradation phenomenon of the tunnel linings in cold regions. Alkali-activated slag concrete (ASC) has a better freeze-thaw resistance, which can be used for tunnel lining in severe frigid regions. Freeze-thaw resistance, performance mechanism of ASC and microstructure were investigated by freeze-thaw cycle, X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis. The experimental results show that, ASC has excellent freeze-thaw resistance, and hydration products of ASC are mostly C-S-H, alkaline aluminosilicate. ASC has a good compact degree and uniformity of structure, and its high compressive strength also makes high freeze-thaw resistance. ASC may be selected as tunnel lining production materials in severe frigid regions because of the less reduction in the dynamic elastic modulus and mass loss of concrete.

Experiment Study on the Effect of GGBFS on Frost Resistance of Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 207-212 ◽  
Author(s):  
Shi Yi Zhang ◽  
Ying Fang Fan ◽  
Qi Wang
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Plain Concrete ◽  
Industrial Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Scanning Electron

High volume utilization of industrial wastes and by products is the solution for high disposal coast. The anti-frost of high performance concrete is a key factor for safe utilization of concrete structure containing industrial wastes under severe environment. In this paper, to understand the property on anti-frost of high performance containing ground granulated blast furnace slag (GGBFS) under cold marine environment. Some comparison studies were conducted on plain concrete by rapid freeze-thaw cycle test. During the rapid freeze-thaw cycle test, the mass loss and relative elastic modulus were measured regularly at the prescribed conditioning ages. The development of microstructure in concrete was analyzed through scanning electron microscopy (SEM) and X-ray diffraction (XRD). The rapid freeze-thaw cycle test results show that the plain concrete was destroyed severely at 150 freeze-thaw cycles. After 225 freeze-thaw cycles, the mass loss and the relative dynamic modulus of elasticity of GGBFS concrete decrease 1.3% and 26.11%, respectively, that indicates that GGBFS significantly improve the anti-frost performance of concrete; The addition of GGBFS can accelerate the cement hydration reaction, promote more Ca (OH)2 crystals shift to C-S-H gel and help to increase the density of the micro-structure of concrete, which can prevent the formation of micro-cracks and suppress the propagation of cracks and thus effectively improve the durability of concrete. KEY WORDS: GGBFS; freeze-thaw durability; microstructure; scanning electron microscopy; X-ray diffraction.

Resistance of Concrete to Na2SO4 Freeze-Thaw Cycles and Failure Mechanism Analysis

2016 ◽  
Vol 711 ◽  
pp. 335-342 ◽  
Author(s):  
Guo Li ◽  
Jian Min Du ◽  
Xiao Suo Wu ◽  
Kun Yang
Keyword(s):  
Tap Water ◽  
Mechanism Analysis ◽  
X Ray Diffraction ◽  
Freeze Thaw ◽  
Ettringite Formation ◽  
Mass Losses ◽  
Thaw Cycle ◽  
Concrete Failure ◽  
Gypsum Formation ◽  
Freeze Thaw Cycle

Rapid freeze–thaw cycle experiments were carried out on concrete specimens with 0.4, 0.5, and 0.6 water–cement (w/c) ratio in 0% (tap water), 1%, and 5% Na2SO4 solutions, respectively, to study the performance of ordinary concrete resistance to sulfate freeze–thaw cycle. The specimens underwent visual inspection, and mass losses and relative dynamic elastic modulus (RDEM) were measured regularly. Scanning electron microscope observation and X-ray diffraction analysis were conducted on partial specimens after the freeze–thaw cycle experiment. Research results show that due to the coupling effects of freeze–thaw cycle and sulfate corrosion, freeze–thaw cycles of concrete in Na2SO4 solution caused more damages than in tap water. Higher Na2SO4 concentration produced severe damages. Concrete with different w/c ratios exhibit different sulfate freeze–thaw cycle resistances, and concrete with lower w/c ratio usually produces stronger resistance. RDEM loss is considered the control index to determine concrete failure. The corrosion products in Na2SO4 solution freeze–thaw cycle are mainly ettringite and gypsum. With the increase in Na2SO4 concentration, ettringite formation gradually decreases and gypsum formation gradually increases.

scholarly journals Plasticization of Cottonseed Protein/Polyvinyl Alcohol Blend Films

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2096 ◽  
Author(s):  
Wenjie Chen ◽  
Jiao Ding ◽  
Xuming Yan ◽  
Wei Yan ◽  
Ming He ◽  
...  
Keyword(s):  
Food Packaging ◽  
Barrier Properties ◽  
Poly Vinyl Alcohol ◽  
Oxygen Barrier ◽  
X Ray Diffraction ◽  
Cottonseed Protein ◽  
X Ray ◽  
Blend Films ◽  
Promising Strategy ◽  
Potential Applications

The use of waste plant protein obtained from underutilized and non-food-producing plants may be a promising strategy in the development of bioactive packaging. A series of blend films were prepared by casting from cottonseed protein (CP) and poly(vinyl alcohol) (PVA) and modified with different plasticizers. The morphology, structure, and crystallinity of each of the blend films were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. CP and PVA were found to be compatible in the appropriate ratios, and the CP/PVA blend films were partially crystalline. We compared the effects that four plasticizers, i.e., glycerol, triethanolamine (TEA), ethylene glycol, and polyethylene glycol, had on the performance of the CP/PVA blend films. Plasticizers altered the degree of interaction between CP and PVA, which changed the secondary structure of the CP but had little effect on the crystallinity of CP/PVA blend films. Among the different plasticizers tested, TEA was the most efficient at improving the elongation at the break, tensile strength, and oxygen barrier properties of the CP/PVA blend films. Such CP/PVA blend films plasticized using TEA can, therefore, be considered emerging and promising plastics for potential applications in food packaging and flower planting applications.

PREPARATION AND CHARACTERISTICS OF SANDWICHED POLYMER/MAGNETIC PARTICLES/POLYMER MAGNETIC NANOMICROSPHERES

2002 ◽  
Vol 01 (05n06) ◽  
pp. 701-705 ◽  
Author(s):  
XIA HONG ◽  
XINTONG ZHANG ◽  
XIN CHEN ◽  
LI XU ◽  
YANMEI LIU ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Magnetic Particles ◽  
Magnetic Composite ◽  
Polymer Shell ◽  
Template Polymerization ◽  
Wide Ph Range ◽  
Potential Applications ◽  
Multicomponent Polymer ◽  
Ph Range ◽  
Superparamagnetic Properties

A template polymerization approach is reported to prepare uniform functional sandwiched magnetic composite nanomicrospheres with polymer core, magnetic Fe 3 O 4 mezzanine and multicomponent polymer shell. The fine superparamagnetic properties, thermostability and stability in a wide pH range of aqueous solution made the composite mirospheres had the potential applications in biology and medicine.

scholarly journals Novel Hydrogels of Chitosan and Poly (vinyl alcohol) Reinforced with Inorganic Particles of Bioactive Glass

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 691
Author(s):  
O. Sánchez-Aguinagalde ◽  
Ainhoa Lejardi ◽  
Emilio Meaurio ◽  
Rebeca Hernández ◽  
Carmen Mijangos ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Drug Release ◽  
Bioactive Glass ◽  
Vinyl Alcohol ◽  
Release Kinetics ◽  
The Body ◽  
Poly Vinyl Alcohol ◽  
X Ray Diffraction ◽  
Inorganic Particles ◽  
Release Studies

Chitosan (CS) and poly (vinyl alcohol) (PVA) hydrogels, a polymeric system that shows a broad potential in biomedical applications, were developed. Despite the advantages they present, their mechanical properties are insufficient to support the loads that appear on the body. Thus, it was proposed to reinforce these gels with inorganic glass particles (BG) in order to improve mechanical properties and bioactivity and to see how this reinforcement affects levofloxacin drug release kinetics. Scanning electron microscopy (SEM), X-ray diffraction (XRD), swelling tests, rheology and drug release studies characterized the resulting hydrogels. The experimental results verified the bioactivity of these gels, showed an improvement of the mechanical properties and proved that the added bioactive glass does affect the release kinetics.

scholarly journals Carbon-coated magnetic particles increase tissue temperatures after laser irradiation

2015 ◽  
Vol 08 (05) ◽  
pp. 1550018 ◽  
Author(s):  
Shupeng Liu ◽  
Na Chen ◽  
Fufei Pang ◽  
Zhengyi Chen ◽  
Tingyun Wang
Keyword(s):  
Laser Irradiation ◽  
Magnetic Particles ◽  
Laser Energy ◽  
Thermal Therapy ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fbg Sensor ◽  
Transmission Electron ◽  
Carbon Coated

Purpose: This work focused on the investigation the hyperthermia performance of the carbon-coated magnetic particles (CCMPs) in laser-induced hyperthermia. Materials and methods: We prepared CCMPs using the organic carbonization method, and then characterized them with transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectrophotometry, vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). In order to evaluate their performance in hyperthermia, the CCMPs were tested in laser-induced thermal therapy (LITT) experiments, in which we employed a fully distributed fiber Bragg grating (FBG) sensor to profile the tissue's dynamic temperature change under laser irradiation in real time. Results: The sizes of prepared CCMPs were about several micrometers, and the LITT results show that the tissue injected with the CCMPs absorbed more laser energy, and its temperature increased faster than the contrast tissue without CCMPs. Conclusions: The CCMPs may be of great help in hyperthermia applications.

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