Nanocrystalline Cellulose/Polyvinylpyrrolidone Fibrous Composites Prepared by Electrospinning and Thermal Crosslinking

Nanocellulose/polyvinylpyrrolidone (nCel/PVP) fibrous composite materials containing rod-like nanocrystalline cellulose particles with the lengths varying in the range from 100 to 2000 nm were prepared by using DC electrospinning. The particle size had a strong effect on the precursor viscosity, process efficiency, and resulting fiber diameter. The thermal crosslinking of nCel/PVP composite nanofibers with up to 1.0 : 8.0 nCel/PVP weight ratio resulted in fibrous membranes with textural, air transport, and mass swelling properties varying significantly with the size of cellulose particles. The presence of nCel particles increased the oxidation resistance of PVP during the crosslinking and affected the morphological changes of nCel/PVP fibrous membranes in aqueous solutions. Particles with the smallest size improved the strength of the membrane but decreased its mass swelling capacity, whereas the larger particles led to a more porous and flexible, but mechanically weaker, membrane structure with a higher swelling ability. Thus, by using the nCel particles of different size and shape, the properties of nCel/PVP composite fibrous membranes can be tailored to a specific application.

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Antibacterial Properties of Nanosilver PLLA Fibrous Membranes

Journal of Nanomaterials ◽

10.1155/2009/168041 ◽

2009 ◽

Vol 2009 ◽

pp. 1-5 ◽

Cited By ~ 9

Author(s):

Lin Li ◽

Yi Li ◽

Jiashen Li ◽

Lei Yao ◽

Arthur F. T. Mak ◽

...

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Silver Nanoparticles ◽

Antibacterial Properties ◽

Weight Ratio ◽

Antibacterial Effects ◽

E Coli ◽

Fibrous Membranes ◽

Composite Fibrous Membranes

Nanosilver has been studied as a valuable material for it strong antibacterial effects. In this study, we investigated the antibacterial properties of nano silver Poly-L-Lactic acid (Ag/PLLA) composite fibrous membranes. Ag/PLLA fibrous membranes were prepared with silver nanoparticles having weight ratio of silver nanoparticles to PLLA at 5% (w/w). In vitro antibacterial tests were performed usingEscherichia coli(E. coli) andStaphylococcus aureus(Staph.) to determine the antibacterial capability of the Ag/PLLA fibrous membranes. As the results suggested, Ag/PLLA fibrous membranes showed strong antibacterial properties. Thus, Ag/PLLA fibrous membrane can be used as an antibacterial scaffold for tissue engineering.

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Chondroitin Sulfate-Based Cryogels for Biomedical Applications

Gels ◽

10.3390/gels7030127 ◽

2021 ◽

Vol 7 (3) ◽

pp. 127

Author(s):

Sahin Demirci ◽

Mehtap Sahiner ◽

Betul Ari ◽

Aydin K. Sunol ◽

Nurettin Sahiner

Keyword(s):

Tissue Engineering ◽

Chondroitin Sulfate ◽

Biomedical Applications ◽

Blood Clotting ◽

Weight Ratio ◽

Halloysite Nanotubes ◽

The Other ◽

Swelling Properties ◽

Swelling Capacity ◽

Alpha Glucosidase

Cryogels attained from natural materials offer exceptional properties in applications such as tissue engineering. Moreover, Halloysite Nanotubes (HNT) at 1:0.5 weight ratio were embedded into CS cryogels to render additional biomedical properties. The hemolysis index of CS cryogel and CS:HNT cryogels was calculated as 0.77 ± 0.41 and 0.81 ± 0.24 and defined as non-hemolytic materials. However, the blood coagulation indices of CS cryogel and CS:HNT cryogels were determined as 76 ± 2% and 68 ± 3%, suggesting a mild blood clotting capability. The maximum% swelling capacity of CS cryogel was measured as 3587 ± 186%, 4014 ± 184%, and 3984 ± 113%, at pH 1.0, pH 7.4 and pH 9.0, respectively, which were reduced to 1961 ± 288%, 2816 ± 192, 2405 ± 73%, respectively, for CS:HNT cryogel. It was found that CS cryogels can hydrolytically be degraded 41 ± 1% (by wt) in 16-day incubation, whereas the CS:HNT cryogels degraded by 30 ± 1 wt %. There is no chelation for HNT and 67.5 ± 1% Cu(II) chelation for linear CS was measured. On the other hand, the CS cryogel and CS:HNT cryogel revealed Cu(II) chelating capabilities of 60.1 ± 12.5%, and 43.2 ± 17.5%, respectively, from 0.1 mg/mL Cu(II) ion stock solution. Additionally, at 0.5 mg/mL CS, CS:HNT, and HNT, the Fe(II) chelation capacity of 99.7 ± 0.6, 86.2 ± 4.7% and only 11.9 ± 4.5% were measured, respectively, while no Fe(II) was chelated by linear CS chelated Fe(II). As the adjustable and controllable swelling properties of cryogels are important parameters in biomedical applications, the swelling properties of CS cryogels, at different solution pHs, e.g., at the solution pHs of 1.0, 7.4 and 9.0, were measured as 3587 ± 186%, 4014 ± 184%, and 3984 ± 113%, respectively, and the maximum selling% values of CS:HNT cryogels were determined as 1961 ± 288%, 2816 ± 192, 2405 ± 73%, respectively, at the same conditions. Alpha glucosidase enzyme interactions were investigated and found that CS-based cryogels can stimulate this enzyme at any CS formulation.

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Swelling Properties and Permeability of GMZ Bentonite-Sand Mixtures during Different Solutions Infiltration

Sustainability ◽

10.3390/su13041622 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1622

Author(s):

Yu-Ping Wang ◽

Zhe Wang ◽

Yu Zhao ◽

Fa-Cheng Yi ◽

Bao-Long Zhu

Keyword(s):

Swelling Pressure ◽

Development Stage ◽

Gmz Bentonite ◽

Test Results ◽

X Ray Diffraction ◽

Swelling Properties ◽

Swelling Capacity ◽

Slow Expansion ◽

Expansion Stage ◽

Chemical Solutions

In China, Gaomiaozi (GMZ) bentonite is recognized as a barrier material for isolating nuclear waste. Different chemical solutions may change the hydraulic conductivity and swelling capacity of bentonite. Consequently, a series of swelling pressure and permeability experiments was carried out on bentonite-sand mixtures with various dry densities and infiltrating solutions. X-ray diffraction (XRD) and the field emission scanning electron microscope (FESEM) were carried out on the samples experiencing the tests to identify the influence of chemistry pore solutions upon the mineralogical and microstructure changes. The results show that the swelling pressure experienced rapid swelling, slow expansion, and the stable expansion stage for the specimens of infiltrating solutions except for NaOH. For the specimens infiltrated with NaOH solutions, the swelling pressure experienced rapid increases, slow decreases, and a stable development stage. With hyper-alkaline and hyper-salinity infiltration, the swelling pressure decreased, and the permeability increased. In addition, swelling pressure attained stability more quickly on contact with hyper-alkaline and hyper-salinity solutions. Comparing the test results, the results indicate that the influence of NaOH on the expansion and permeability was higher than NaCl-Na2SO4 at the same concentration.

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Synthesis, Applications and Swelling Properties of Poly (Sodium Acrylate-Coacrylamide) Based Superabsorbent Hydrogels

Journal of the chemical society of pakistan ◽

10.52568/000784/jcsp/41.04.2019 ◽

2019 ◽

Vol 41 (4) ◽

pp. 668-668

Author(s):

Saud Hashmi Saud Hashmi ◽

Saad Nadeem Saad Nadeem ◽

Zahoor Awan Zahoor Awan ◽

Adeel ur Rehman Adeel ur Rehman ◽

Ahsan Abdul Ghani Ahsan Abdul Ghani

Keyword(s):

Rate Constant ◽

Polymeric Materials ◽

Water Soluble ◽

Ion Concentration ◽

Copolymer Composition ◽

Swelling Properties ◽

Swelling Capacity ◽

Swelling Rate ◽

Crosslinker Concentration ◽

Superabsorbent Hydrogels

Superabsorbent hydrogels constitute a group of polymeric materials with three-dimensional network structure, which can swell to absorb an enormous amount of water or aqueous solutions. This property enables various commercial applications of hydrogels such as water holding capability in agriculture and superabsorbent material for baby diapers. Several novel superabsorbent hydrogels based on acrylic acid-co-acrylamide copolymers were synthesized under variation of copolymer compositions through free radical polymerization. N,N’methylenebisacrylamide (MBA) was used as a water soluble crosslinker and potassium persulphate (KPS) as an initiator. Effect of varying the copolymer composition, change in crosslinker concentration, and effect of environmental parameters (pH, temperature, and ion concentration) on both swelling capacity and swelling rate were examined. These gel shows maximum swelling at neutral pH-7, whereas increasing salt concentration in water decrease the swelling capacity. It was found interesting that an increase in crosslinker concentration from 0.020% to 0.16%, the swelling capacity decreases up to 70% while the swelling rate increases from 0.007g water/g dry hydrogel sec to 0.024g water/g dry hydrogel sec, respectively because there is a compromise exists between entropic spring forces between network connection points and the hydrostatic pressure of the water diffusing into the gels. Dynamic swelling curve obtained were fitted to the three different kinetic models namely Peleg’s kinetic model, pseudo 1st order as proposed by Lagergen and pseudo 2nd order kinetics. All these models provided a good agreement with the experimental data; However on the bases of statistical parameters (RMSE, R2 and X2) the Peleg’s model was selected as the most appropriate model for this study. Analyzing rate constant for Peleg’s models at different swelling temperatures disclosed that increasing temperature could only increase the swelling rate without affecting the swelling capacity of the hydrogels. Experimental values for rate constant k1 of Peleg’s model at different temperature shows a sharp decrease from 0.57545 at 30 oC to 0.1535 at 75 oC that contemplated the rate of swelling at 75 oC was 65% faster than that of 30 oC. The diffusion mechanisms in hydrogels were proven to be tailorable by increasing cross-linker concentration and temperature, leading towards the Fickian type diffusion behavior. The synthesized superabsorbent hydrogels were also tested for water retention applications in agriculture.

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A Novel Hydrogel Based on Renewable Materials for Agricultural Application

International Journal of Polymer Science ◽

10.1155/2020/8363418 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Silvie Durpekova ◽

Kateryna Filatova ◽

Jaroslav Cisar ◽

Alena Ronzova ◽

Erika Kutalkova ◽

...

Keyword(s):

Citric Acid ◽

Water Uptake ◽

Agricultural Product ◽

Cellulose Derivatives ◽

Gravimetric Analysis ◽

Renewable Materials ◽

Swelling Properties ◽

Arable Farming ◽

Swelling Capacity ◽

The Stability

This study details the design and characterization of a new, biodegradable, and renewable whey/cellulose-based hydrogel (i.e., agricultural hydrogel). This was formulated from cellulose derivatives (carboxymethylcellulose (CMC) and hydroxyethylcellulose (HEC)) and acid whey cross-linked with citric acid, with the aim to obtain an agricultural product with a high swelling capacity to uphold the quality of soil and conserve water resources. With regard to the swelling behaviour of the prepared hydrogels, the authors initially assessed the swelling ratio and capacity for water uptake. Evaluating the chemical structure of the hydrogel and its thermal and viscoelastic properties involved performing Fourier transform infrared spectroscopy, differential scanning colorimetry, thermal gravimetric analysis, and rheological measurement of the hydrogel films. According to preliminary results, sufficient swelling capacity and stiffness were observed in a hydrogel prepared with 3% CMC and HEC, cross-linked with 5% citric acid. Moreover, the kinetics of water uptake revealed a promising capacity that was sustainable after 5 drying and swelling cycles. The results confirmed that the stability of the hydrogel was enhanced by the presence of the citric acid. As a consequence, it is necessary to utilize an appropriate cross-linking concentration and abide by certain conditions to ensure the swelling properties of the prepared hydrogel are sufficient. Further investigation of the topic, especially in relation to applications in soil, could confirm if the whey-cellulose-based hydrogel is actually suitable for agricultural use, thereby contributing to the advancement of sustainable arable farming.

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Preparation and swelling behaviour of a novel anti-salt superabsorbent hydrogel based on kappa-carrageenan and sodium alginate grafted with polyacrylamide

e-Polymers ◽

10.1515/epoly.2004.4.1.275 ◽

2004 ◽

Vol 4 (1) ◽

Cited By ~ 7

Author(s):

Ali Pourjavadi ◽

Hossein Ghasemzadeh ◽

Hossein Hosseinzadeh

Keyword(s):

Sodium Alginate ◽

Graft Copolymerization ◽

Weight Ratio ◽

Homogeneous Solution ◽

Water Soluble ◽

Swelling Kinetics ◽

Salt Solutions ◽

Superabsorbent Hydrogel ◽

Swelling Capacity ◽

Kappa Carrageenan

Abstract A novel superabsorbent hydrogel was synthesized via crosslinking graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (κC) and sodium alginate (Na-Alg) backbones in a homogeneous solution. Methylenebisacrylamide (MBA) and potassium persulfate (KPS) were applied as water-soluble crosslinker and initiator, respectively. FTIR spectroscopy was used for confirming the structure of the final product. A mechanism for superabsorbent hydrogel formation was also suggested. The parameters affecting the swelling capacity of the synthesized hydrogel, i.e., κC-Alg weight ratio, concentration of AAm, MBA and KPS, as well as reaction temperature were systematically optimized for obtaining maximum absorbency. The swelling capacity of hydrogels was also measured in various salt solutions (LiCl, NaCl, KCl, MgCl2, CaCl2, SrCl2, BaCl2, and AlCl3). Due to their high swelling ability in salt solutions, the hydrogels may be referred to as ‘anti-salt superabsorbent’ polymers. The overall activation energy for the graft copolymerization reaction was found to be 374 kJ/mol. The swelling kinetics of the hydrogels in distilled water and in saline solution (0.9 wt.-% NaCl) was investigated.

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Organic/Inorganic Superabsorbent Hydrogels Based on Xylan and Montmorillonite

Journal of Nanomaterials ◽

10.1155/2014/675035 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 7

Author(s):

Shuang Zhang ◽

Ying Guan ◽

Gen-Que Fu ◽

Bo-Yang Chen ◽

Feng Peng ◽

...

Keyword(s):

Compressive Modulus ◽

Cross Linking ◽

Swelling Properties ◽

Ph Values ◽

Swelling Capacity ◽

Wide Ph Range ◽

Grafting Copolymerization ◽

Ph Range ◽

Influence Of Ph ◽

Superabsorbent Hydrogels

The unique organic/inorganic superabsorbent hydrogels based on xylan and inorganic clay montmorillonite (MMT) were prepared via grafting copolymerization of acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) withN,N-methylenebisacrylamide (MBA) as a cross-linking agent and potassium persulfate (KPS) as an initiator. The effect of variables on the swelling capacity of the hydrogels, such as the weight ratios of MMT/xylan, MBA/xylan, and AMPS/AA, was systematically optimized. The results indicated that the superabsorbent hydrogels comprised a porous cross-linking structure of MMT and xylan with side chains that carry carboxylate, carboxamide, and sulfate. The hydrogels exhibit the high compressive modulus (E), about 35–55 KPa, and the compression strength of the hydrogels increased with an increment of the MMT content. The effect of various cationic salt solutions (LiCl, CaCl2, and FeCl3) on the swelling has the following order: Li+> Ca2+> Fe3+. Furthermore, the influence of pH values on swelling behaviors showed that the superabsorbent composites retained around 1000 g g−1over a wide pH range of 6.0–10.0. The xylan-based hydrogels with the high mechanical and swelling properties are promising for the applications in the biomaterials area.

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Investigation of superabsorbent polymer absorbency at reduced chemical potential of water

MATEC Web of Conferences ◽

10.1051/matecconf/201926804010 ◽

2019 ◽

Vol 268 ◽

pp. 04010 ◽

Cited By ~ 2

Author(s):

Ariel Melendres ◽

Judy An Antang ◽

Christian Jake Manacob

Keyword(s):

Chemical Potential ◽

Chloride Concentration ◽

Crosslinking Density ◽

Superabsorbent Polymer ◽

Sodium Chloride Concentration ◽

Swelling Properties ◽

Superabsorbent Polymers ◽

Swelling Capacity ◽

Major Parameter ◽

Different Types

Different types of superabsorbent polymers (SAP) exhibiting varied absorbency properties were investigated for their performances at varying concentrations of an electrolyte. Water chemical potential, which is a function of concentration and pressure, was interpreted as a major parameter for absorbency and swelling properties of SAP. Superabsorbent polymers that were investigated gave different values of permeability which was carried out in a layer of swelled superabsorbent polymer. This result revealed differences on the structure of the superabsorbent polymers particularly on the crosslinking density. SAP’s absorbency properties were further tested and a correlation between the quantity of absorption and the chemical potential of water in terms of sodium chloride concentration was developed using experimental data on free swelling capacity and absorption under pressure. Results showed decreasing quantity of absorption by the superabsorbent polymers with decreasing chemical potential of water with higher reduction in the absorbency at higher pressure applied on the swelled SAP.

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Synthesis and absorbency of gelatin-graft-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with saltand pH-responsiveness properties

e-Polymers ◽

10.1515/epoly.2006.6.1.728 ◽

2006 ◽

Vol 6 (1) ◽

Cited By ~ 5

Author(s):

Ali Pourjavadi ◽

Mohammad Sadeghi ◽

Mohammad Mahmodi Hashemi ◽

Hossein Hosseinzadeh

Keyword(s):

Weight Ratio ◽

Ammonium Persulfate ◽

Switching Behavior ◽

Polymerization Reaction ◽

Sodium Acrylate ◽

Swelling Kinetics ◽

Superabsorbent Hydrogel ◽

Swelling Capacity ◽

Bioactive Agents ◽

Kinetics Of

AbstractIn 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 was also investigated in various salt solutions. Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1.0 and 13.0. It showed a reversible pH-responsive behavior at pHs 2.0 and 7.0. This on-off switching behavior makes the synthesized hydrogels an excellent candidate for controlled delivery of bioactive agents. Finally, the swelling kinetics of the synthesized hydrogels with various particle sizes was preliminarily investigated.

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