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hydrogels
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Carrageenan-g-poly(sodium acrylate)/kaolin superabsorbent hydrogel composites: Synthesis, characterisation and swelling behaviour
, Article Polymers and Polymer Composites ; Volume 15, Issue 1 , 2007 , Pages 43-51 ; 09673911 (ISSN) ; Hosseinzadeh, H ; Mahdavinia, G. R ; Zohuriaan Mehr, M. J ; Sharif University of Technology
Rapra Technology Ltd
2007
Abstract
A novel superabsorbent hydrogel composite based on kappa-carrageenan (κC) was prepared by graft copolymerisation of acrylic acid (AA) in the presence of kaolin using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The synthetic variables (i.e. AA, MBA and APS concentration, and the amount of kaolin) affecting the water absorbency of the resulting superabsorbent composite were studied. Evidence of grafting and kaolin interaction was obtained by comparing the FTIR spectra of the initial substrates and of the superabsorbent composite. A new absorption band at 1722 cm-1 in the composite spectrum confirmed the kaolin-organic polymer linkage....
Synthesis and absorbency of gelatin-graft-poly(sodium acrylate-co- acrylamide) superabsorbent hydrogel with saltand pH-responsiveness properties
, Article E-Polymers ; 2006 , Pages 1-15 ; 16187229 (ISSN) ; Sadeghi, M ; Mahmodi Hashemi, M ; Hosseinzadeh, H ; Sharif University of Technology
European Polymer Federation
2006
Abstract
In this article, we synthesize a novel gelatin-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and acrylamide (AAm) onto gelatin backbones. The polymerization reaction was carried out in an aqueous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N-methylene bisacrylamide (MBA) as a crosslinker. The hydrogel structures were confirmed by FTIR spectroscopy. The effect of grafting variables, i.e. concentration of MBA and APS, AA/AAm weight ratio, and reaction time and temperature, was systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The swelling behavior of these absorbent polymers...
Optimization of synthetic conditions of a novel collagen-based superabsorbent hydrogel by Taguchi method and investigation of its metal ions adsorption
, Article Journal of Applied Polymer Science ; Volume 102, Issue 5 , 2006 , Pages 4878-4885 ; 00218995 (ISSN) ; Salimi, H ; Amini Fazl, M. S ; Kurdtabar, M ; Amini Fazl, A. R ; Sharif University of Technology
2006
Abstract
A novel biopolymer-based superabsorbent hydrogel was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the hydrolyzed collagen, in the presence of a crosslinking agent and a free radical initiator. The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis reaction based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L16 orthogonal array with three factors and four levels were chosen. The critical parameters that have been selected for this study are crosslinker (N,N′-methylene bisacrylamide), initiator (potassium persulfate), and monomer...
Biomimetic ultraflexible piezoresistive flow sensor based on graphene nanosheets and PVA hydrogel
, Article Advanced Materials Technologies ; 2021 ; 2365709X (ISSN) ; Moradi, H ; Wu, S ; Han, Z. J ; Razmjou, A ; Asadnia, M ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Flow sensors play a critical role in monitoring flow parameters, including rate, velocity, direction, and rotation frequency. In this paper, inspired by biological hair cells in the human vestibular system, an innovative flow sensor is developed based on polyvinyl alcohol (PVA) hydrogel nanocomposites with a maze-like network of vertically grown graphene nanosheets (VGNs). The VGNs/PVA hydrogel absorbs a copious amount of water when immersed in water, making the sensor highly sensitive to tiny stimuli underwater. The sensor demonstrates a high sensitivity (5.755 mV (mm s−1)−1) and extremely low velocity detection (0.022 mm s−1). It also reveals outstanding performance in detecting...
Biomimetic ultraflexible piezoresistive flow sensor based on graphene nanosheets and PVA hydrogel
, Article Advanced Materials Technologies ; 2021 ; 2365709X (ISSN) ; Moradi, H ; Wu, S ; Han, Z. J ; Razmjou, A ; Asadnia, M ; Sharif University of Technology
John Wiley and Sons Inc
2021
Abstract
Flow sensors play a critical role in monitoring flow parameters, including rate, velocity, direction, and rotation frequency. In this paper, inspired by biological hair cells in the human vestibular system, an innovative flow sensor is developed based on polyvinyl alcohol (PVA) hydrogel nanocomposites with a maze-like network of vertically grown graphene nanosheets (VGNs). The VGNs/PVA hydrogel absorbs a copious amount of water when immersed in water, making the sensor highly sensitive to tiny stimuli underwater. The sensor demonstrates a high sensitivity (5.755 mV (mm s−1)−1) and extremely low velocity detection (0.022 mm s−1). It also reveals outstanding performance in detecting...
Novel sulfobetaine-sulfonic acid-contained superswelling hydrogels
, Article Polymers for Advanced Technologies ; Volume 16, Issue 9 , 2005 , Pages 659-666 ; 10427147 (ISSN) ; Faraji Dana, S ; Zohuriaan Mehr, M. J ; Sharif University of Technology
2005
Abstract
Novel hydrogels based on zwitterionic monomer [3-(methacrylamido)propyl] dimethyl (3-sulfopropyl) ammonium hydroxide (MPDSAH) and a strong acid monomer (2-acrylamido-2-methylpropane sulfonic acid, AMPS) were synthesized through solution polymerization under normal conditions to achieve nearly quantitative gel yield. The structure of the gels was confirmed using infrared spectroscopy. Thermal properties were simultaneously studied by differential scanning calorimetry and thermogravimetric analysis (DSC/TGA). The effects of the polymerization variables on the swelling capacity of the products were investigated. It was found that, in a certain range of the monomers mol ratio, increase of AMPS...
Biomimetic ultraflexible piezoresistive flow sensor based on graphene nanosheets and pva hydrogel
, Article Advanced Materials Technologies ; Volume 7, Issue 1 , 2022 ; 2365709X (ISSN) ; Moradi, H ; Wu, S ; Han, Z. J ; Razmjou, A ; Asadnia, M ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
Flow sensors play a critical role in monitoring flow parameters, including rate, velocity, direction, and rotation frequency. In this paper, inspired by biological hair cells in the human vestibular system, an innovative flow sensor is developed based on polyvinyl alcohol (PVA) hydrogel nanocomposites with a maze-like network of vertically grown graphene nanosheets (VGNs). The VGNs/PVA hydrogel absorbs a copious amount of water when immersed in water, making the sensor highly sensitive to tiny stimuli underwater. The sensor demonstrates a high sensitivity (5.755 mV (mm s−1)−1) and extremely low velocity detection (0.022 mm s−1). It also reveals outstanding performance in detecting...
Fabrication of a magnetic alginate-silk fibroin hydrogel, containing halloysite nanotubes as a novel nanocomposite for biological and hyperthermia applications
, Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) ; Sadat, Z ; Aghamirza Moghim Aliabadi, H ; Ganjali, F ; Kashtiaray, A ; Salimi Bani, M ; Komijani, S ; Ahadian, M. M ; salehpour, N ; Ahangari Cohan, R ; Maleki, A ; Sharif University of Technology
Nature Research
2022
Abstract
In this study, the main focus was on designing and synthesizing a novel magnetic nanobiocomposite and its application in hyperthermia cancer treatment. Regarding this aim, sodium alginate (SA) hydrogel with CaCl2 cross-linker formed and modified by silk fibroin (SF) natural polymer and halloysite nanotubes (HNTs), followed by in situ Fe3O4 magnetic nanoparticles preparation. No important differences were detected in red blood cells (RBCs) hemolysis, confirming the high blood compatibility of the treated erythrocytes with this nanobiocomposite. Moreover, the synthesized SA hydrogel/SF/HNTs/Fe3O4 nanobiocomposite does not demonstrate toxicity toward HEK293T normal cell line after 48 and 72 h....
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor) ; Zohurian Mehr, Mohammad Jalal (Supervisor)
Abstract
Polyampholyte hydrogels are hydrophilic networks that contain both positively- and negatively-charged functional groups on their structure. Polysulfobetaines are the most important type of polyampholytes, which have been extensively studied. However, these hydrogels exhibited poor gel strength causing limitation of their applications. Consequently, much attention has been focused on the preparation of nanocomposite hydrogels with high gel strength and lower cost using organomodified clays. In this project, Novel polyampholytic superabsorbing nanocomposites based on the zwitterionic sulfobetaine monomer [3-(methacrylamido)propyl)]dimethyl(3-sulfopropyl) ammonium hydroxide (MPDSAH) were...
Synthesis of Superabsorbents Based on Agar and Modified Agar and Investigation of their Applications in Controlled Release of Potassium Nitrate as a Sample of Ionic Fertilizers
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor)
Abstract
This thesis focouses on the preparation and super-swelling behavior of two superabsorbent hydrogel. In the first section, a new superabsorbent hydrogel based on agar was prepared and the effect of the ratio of some components(AA, AAM, MBA, APS and agar) on the swelling capasity of the hydrogel was studied. Maximum water absorbency of the optimized final product was found to be 614.5 g/g in distilled water. The structure of the hydrogel was characterized by FT-IR method and morphology of the samples was examined by scanning electron microscopy(SEM). Swelling behavior properties of optimized hydrogel sample in different swelling medium were investigated. In the second section, we report the...
Synthesis and Investigation of the Swelling Behavior of Superabsorbents Based on Gelatin and k-Carrageenan and Loading of KNO3 as aModel of Agrochemical Onto Them
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi , Ali (Supervisor)
Abstract
This thesis focuses on the preparation and super-swelling behavior of a superabsorbent hydrogel based on natural macro-molecules and loading potassium nitrite as an agro-chemical onto it. 1-In this investigation a new type of superabsorbent hydrogel based on Gelatin and k-Carrageenan was prepared and the effect of the feed ratio of some components (acrylic acid, MBA, APS, and agar) on the swelling capacity of the hydrogel was systematically studied. The structure of the hydrogel optimized final product was found to be 1064 g/g in distilled water. The structure of the hydrogel was characterized by FT_IR method and morphology of the samples was examined by scamming electron microscopy (SEM)....
Preparation of Gelatin-Alginate Hydrogel for Using as Cell Culture Scaffold
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohreh (Supervisor) ; Maghsoudi, Vida (Supervisor)
Abstract
Hydrogels are polymeric three-dimensional networks able to swell in the presence of an aqueous medium. Hydrogels from natural proteins and polysaccharides are ideal scaffolds for tissue engineering since they resemble the extracellular matrices of tissue comprised of various amino acids and sugar-based macromolecules.The biocompatible and biodegradable hydrogel scaffolds are promising materials for tissue engineering. Here, we report a new class of hydrogels derived from oxidized alginate (OA) and gelatin. The prepared oxidized alginate was shown to be efficient in crosslinking gelatin, leading to hydrogel formation. The effect of degree of oxidation and concentration of OA on the mechanical...
Preparation of Nanocomposites Based on Poly (Vinyl Alcohol)and Graphene Oxide Via Gamma Irradiation
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor) ; Dadbin, Susan (Co-Advisor)
Abstract
Poly vinyl alcohol/graphene oxide (GO) nanocomposites were made through solution casting method. The nanocomposite were characterized by XRD , FTIR , FESEM , DSC and mechanical measurements. Graphene oxide was irradiated by gamma ray at 35 KGy in a 50/50 water-ethanol solution and then added to PVA aqueous solution in various GO concentrations (0.3 , 0.7 , 1 wt%) and sonicated. The resulting suspensions were cast into petri dishes to make thin films. Also PVA/GO Hydrogels were prepared by gamma irradiation at 20 KGy. It was observed that GO uniformly dispersed within PVA indicating strong interaction through forming hydrogen bonds between hydroxyl groups of PVA and GO surface. Tensile...
Structure, swelling and mechanical behavior of a cationic full-IPN hydrogel reinforced with modified nanoclay
, Article Iranian Polymer Journal (English Edition) ; Volume 24, Issue 5 , May , 2015 , Pages 379-388 ; 10261265 (ISSN) ; Bagheri, R ; Kabiri, K ; Sharif University of Technology
Springer-Verlag London Ltd
2015
Abstract
Despite various applications of hydrogels, they have poor gel strength and low resistance against crack propagation which lead to the limitation of their applications. For overcoming this inherent weakness, the current study has focused on the simultaneous utilization of interpenetrating polymer network (IPN) structure and nanocomposite hydrogels. It is known that IPN and nanocomposite gels can improve gel strength. The combination of IPN and nanocomposite structure was developed in hydrogels for improving gel strength. For this purpose, bentonite was successfully modified with a cationic surfactant, (3-methacrylamidopropyl) trimethyl ammonium chloride (MAPTAC), as intercalate, and...
Effect of different bases and neutralization steps on porosity and properties of collagen-based hydrogels
, Article Polymer International ; Volume 59, Issue 1 , 2010 , Pages 36-42 ; 09598103 (ISSN) ; Kurdtabar, M ; Sharif University of Technology
Abstract
The aim of the work reported was to investigate the effect of bases and neutralization steps on hydrogel microstructures. A series of porous hydrogels with various pore sizes were prepared by neutralizing a conventional hydrogel after gel formation. Scanning electron microscopy was used to characterize the microstructure of the porous hydrogels. The morphology of the samples showed the pores were induced into the hydrogels by water evaporation and gas release resulting from the neutralization process. Experimental results indicated that the hydrogels had an absorbency of 200-220 and 48-50 g g-1 for distilled water and sodium chloride solutions, respectively. A simple method was used to...
Preparation and evaluation of hydrogel composites based on starch-g-PNaMA/eggshell particles as dye biosorbent
, Article Desalination and Water Treatment ; Volume 57, Issue 39 , 2016 , Pages 18144-18156 ; 19443994 (ISSN) ; Darvishi, A ; Sharif University of Technology
Taylor and Francis Inc
Abstract
In this study, eggshell (ES) particles as an available and low-cost waste material were used for preparing hydrogel composites as dye biosorbents. For this purpose, hydrogel composites were prepared through free-radical graft copolymerization of wheat starch and sodium methacrylate (NaMA) in the presence of different contents of ES particles with various size ranges. FTIR spectroscopy confirmed graft copolymerization of NaMA moieties onto starch backbone besides the combination of ES particles with the starch-g-PNaMA matrix. The gel content values were high (>99%), which showed proper graft efficiency for hydrogel composites. Incorporation of ES particles into hydrogel matrix resulted in...
Preparation and characterization of a composite biomaterial including starch micro/nano particles loaded chitosan gel
, Article Carbohydrate Polymers ; Volume 174 , 2017 , Pages 633-645 ; 01448617 (ISSN) ; Bagheri, R ; Solouk, A ; Sharif University of Technology
Abstract
Thermosensitive Chitosan hydrogels which can be injected into defects with minimally invasive approach were prepared. Also starch micro/nano particles were synthesized via water-in-oil (W/O) miniemulsion technique. The starch particles were incorporated into the chitosan hydrogel to prepare injectable thermosensitive hydrogel composites. Tube inverting method, compression tests, swelling studies, XRD, SEM, OM, DLS, UV–vis spectroscopy were used for investigations. Results revealed that increasing crosslinker and surfactant contents and stirring rate leads to particle size reduction. Particle size was modeled using design of experiments (DOE) via the response surface method (RSM). Due to...
An injectable platelet lysate-hyaluronic acid hydrogel supports cellular activities and induces chondrogenesis of encapsulated mesenchymal stem cells
, Article Acta Biomaterialia ; 2018 ; 17427061 (ISSN) ; Abdekhodaie, M. J ; Alvi, M ; Mousavi, A ; Karperien, M ; Dijkstra, P. J ; Sharif University of Technology
Acta Materialia Inc
2018
Abstract
Developing scaffolds that can provide cells and biological cues simultaneously in the defect site is of interest in tissue engineering field. In this study, platelet lysate (PL) as an autologous and inexpensive source of growth factors was incorporated into a cell-laden injectable hyaluronic acid-tyramine (HA-TA) hydrogel. Subsequently, the effect of platelet lysate on cell attachment, viability and differentiation of human mesenchymal stem cell (hMSCs) toward chondrocytes was investigated. HA-TA conjugates having a degree of substitution of 20 TA moieties per 100 disaccharide units were prepared and crosslinked in the presence of horseradish peroxidase and low concentrations of hydrogen...
Fast-swelling superabsorbent hydrogels from poly(2-hydroxy ethyl acrylate-co-sodium acrylate) grafted on starch
, Article Starch/Staerke ; Volume 60, Issue 2 , 2008 , Pages 79-86 ; 00389056 (ISSN) ; Samadi, M ; Ghasemzadeh, H ; Sharif University of Technology
2008
Abstract
Fast-swelling highly porous superabsorbent hydrogels were synthesized through a rapid radical polymerization under normal atmospheric conditions. To synthesize a biopolymer-based superabsorbent hydrogel, 2-hydroxyethyl acrylate (HEA) and sodium acrylate (AANa) were grafted on the starch backbone in an aqueous solution. The graft copolymerization reaction was carried out in the presence of ammonium persulfate (APS) as an initiator and N, N′-methylenebisacrylamide (MBA) as a cross-linker in a homogeneous medium. The chemical structure of the hydrogels was confirmed by FT-IR spectroscopy and thermogravimetric analysis (TGA). The morphology of the samples was examined by scanning electron...
Synthesis and properties of biodegradable hydrogels of κ-carrageenan grafted acrylic acid-co-2-acrylamido-2-methylpropanesulfonic acid as candidates for drug delivery systems
, Article Reactive and Functional Polymers ; Volume 67, Issue 7 , 2007 , Pages 644-654 ; 13815148 (ISSN) ; Barzegar, Sh ; Zeidabadi, F ; Sharif University of Technology
2007
Abstract
Novel types of highly swelling hydrogels were prepared by grafting crosslinked polyacrylic acid-co-poly-2-acrylamido-2-methylpropanesulfonic acid (PAA-co-PAMPS) chains onto κ-carrageenan through a free radical polymerization method. Here, we propose a mechanism for κ-carrageenan-g-PAA-co-PAMPS formation and confirm the hydrogel structure using FTIR spectroscopy. The effect of grafting variables (i.e. concentration of methylenebisacrylamide (MBA), acrylic acid/-2-acrylamido-2-methylpropanesulfonic acid (AA/AMPS) weight ratio, ammonium persulfate (APS), κ-carrageenan, neutralization percent and reaction temperature) were systematically optimized to achieve a hydrogel with a maximum swelling...