Superabsorbent Hydrogel Nanocomposite Research Articles

Development of functional chitosan-based superabsorbent hydrogel nanocomposites for adsorptive removal of Basic Red 46 textile dye

Development of functional chitosan-based superabsorbent hydrogel nanocomposites for adsorptive removal of Basic Red 46 textile dye

Synthesis of poly(acrylamide-co-itaconic acid)/MWCNTs superabsorbent hydrogel nanocomposite by ultrasound-assisted technique: Swelling behavior and Pb (II) adsorption capacity

In this research, the poly (acrylamide-co-itaconic acid)/multi-walled carbon nanotubes (P(AAm-co-IA)/MWCNTs) as a novel superabsorbent hydrogel nanocomposite was synthesized by graft copolymerization of acrylamide (AAm) and itaconic acid (IA) mixture in the presence of the MWCNTs using ammonium persulfate (APS) as a free radical initiator and methylenebisacrylamide (MBA) as a crosslinker under ultrasound-assisted condition. The blank P(AAm-co-IA) hydrogel and its composite with the MWCNTs were characterized by means of SEM, FTIR, XRD and TGA methods. The effects of different parameters such as pH, time, the MWCNTs content and salt solutions on swelling behavior were investigated. The stability of the hydrogel increased by any increase in the MWCNTs content, which might be attributed to the hydrophobic nature of the MWCNTs as well as the increase of the crosslinker density. The water retention capacity (WRC) of the P(AAm-co-IA) hydrogel increased in the presence of the MWCNT (10 wt%). The synthesized hydrogel nanocomposite was studied for Pb (II) adsorption from aqueous solution. The effects of different parameters such as contact time (5–90 min), Pb (II) initial concentration (25–175 mg/L) and initial pH (1.5–4.5) of solution on Pb (II) adsorption were investigated by batch method. In comparison to P(AAm-co-IA) hydrogel, the P(AAm-co-IA)/MWCNTs hydrogel nanocompoite showed better adsorption behavior toward Pb (II). One of the most important aspects of this research was to investigate the effects of ultrasonic waves on polymer matrix and its ability.

Synthesis, characterization, and swelling kinetic study of porous superabsorbent hydrogel nanocomposite based on sulfonated carboxymethylcellulose and silica nanoparticles

New superabsorbent nanocomposite was synthesized by free-radical graft polymerization of sulfonated-carboxymethyl cellulose (SCMC) with acrylic acid (AA) in the presence of polyvinylpyrrolidone (PVP) and silica nanoparticles. Carboxymethyl cellulose (CMC) was first sulfonated using chlorosulfonic acid, and then AA monomers were grafted onto SCMC. FTIR results confirmed that sulfonation of CMC as well as grafting of AA monomers onto SCMC has been performed successfully. Moreover, the presence of silica nanoparticles into superabsorbent nanocomposite was evaluated with EDX analysis. The element mappings show a homogenous distribution of silica nanoparticles throughout the hydrogel nanocomposite. SEM images exhibited porous morphology for hydrogel nanocomposite, which was due to the incorporation of PVP in its network. The experimental findings from TGA analysis indicated that incorporation of PVP and silica nanoparticles into the hydrogel network improved thermal stability of superabsorbent nanocomposite. Swelling kinetic studies revealed that superabsorbent nanocomposite hydrogel had higher equilibrium swelling capacity and swelling rate compared with the neat hydrogel sample. Besides that, superabsorbent nanocomposite depicted excellent salt and pH-sensitive behavior in different saline and pH solutions. As a consequence, this hydrogel nanocomposite acts as useful water reservoir, which might be most profitable in agricultural applications.

PH sensitive release of doxorubicin anticancer drug from gold nanocomposite hydrogel based on poly(acrylic acid) grafted onto salep biopolymer

In this manuscript, synthesis, characterization, swelling behavior, and drug delivery performance of a gold nanocomposite hydrogel (GNH) based on poly(acrylic acid) grafted onto salep, as a biocompatible polymer, are described. Gold nanoparticles (AuNPs) as nanometer base, ammonium persulfate as an initiator, N,N-methylenebisacrylamide as a crosslinker, and acrylic acid as pH sensitive monomer were employed for the preparation of entitled GNH in aqueous solution and their amounts were optimized to reach the highest water absorbance. The synthesized GNHs were fully characterized by using FTIR spectroscopy, thermogravimetric analysis, EDAX spectrum, SEM, TEM, and AFM images, and a mechanism for superabsorbent hydrogel nanocomposite formation was suggested. Swelling kinetics in double-distilled water and the absorbency were also investigated. Furthermore, the on–off switching behaviors of the nanocomposite at different pHs were investigated. Doxorubicin hydrochloride is a chemotherapeutic drug and a hydrophilic molecule, with nitrogen and oxygen in its chemical structure. Because nitrogen and oxygen can bind to gold surfaces with high affinity, most frequently nitrogen- and oxygen-modified ligands are used as stabilizing agents, which interact with the surface of the AuNPs by formation of Au–nitrogen and Au–oxygen bonds. This Au nanoparticle–drug conjugate can be incorporated into the bio-based hydrogel matrices to make a hydrogel nanocomposite system. The pH response of this GNH makes it suitable for acting as a controlled drug delivery system. Furthermore, the role of AuNPs in effective release of doxorubicin is discussed by comparing the release in hydrogel and nanocomposite systems.

Synthesis and Properties of GO‐Doped Porous Hydrogel Nanocomposites with Semi‐Interpenetrating Network Structure

Superabsorbent hydrogel nanocomposites (SHN) with semi‐interpenetrating polymer network (semi‐IPN) are synthesized by the polymerization of acrylamide monomer in a polyethylene glycol aqueous solution in the presence of the octadecylamine (ODA)‐modified graphene oxide (GO‐ODA) nanosheets. The hydrogel composites are characterized by Fourier transform infrared spectroscopy, thermal gravity analysis, and scanning electron microscopy. The water absorbency of the resulting SHN in distilled water and saline solutions are measured. The results show that doping GO‐ODA nanosheets into hydrogel semi‐IPN would enhance both their salt resistance and water retention. Using a simple freezing‐dry method, porous SHN with macroscopically interconnected pores is prepared, which exhibits excellent separation ability for removal of trace water from oils. Based on their better water absorbency, salt resistance, and excellent oil/water separation ability, the resulting SHN has great potentials in a wide range of applications, for example, oil dehydration, absorption, and separation. image

Synthesis of superabsorbent hydrogel nanocomposites for use as hemostatic agent

ABSTRACTUncontrolled hemorrhage continues to be the major cause of death in trauma. In this study, the authors prepared hydrogel nanocomposites (HNCs) using three different nanoparticles, SiO2, natural clinoptilolite (nC), and Ca2+-modified clinoptilolite (mC). Fast-swelling superabsorbent hydrogel was used as a matrix of NCs. The hydrogel and HNCs were characterized by FTIR, XRD, FE-SEM, and TGA. The hemocompatibility of HNCs was evaluated by hemolysis test and blood cells function. HNC formed a physical barrier by dehydrating the injury site and concentrating clotting factors. Additionally, highly charged nanoparticles, promoted local hemostasis by activating the intrinsic pathway of the blood coagulation cascade.

Fabrication and characterization of CMC-based magnetic superabsorbent hydrogel nanocomposites for crystal violet removal

In this research work, novel magnetic superabsorbent hydrogel nanocomposites (MSHNs) based on carboxymethyl cellulose were prepared via a facile “one-pot” two step approach. Magnetic iron oxide nanoparticles were in situ synthesized and incorporated into carboxymethyl cellulose/poly(acrylic acid) polymer hydrogel. The morphology and chemical composition of MSHNs as well as the presence of magnetic iron oxide nanoparticles were evaluated by using Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X-Ray diffraction, ultraviolet–visible spectroscopy, thermogravimetric analysis, and vibrating sample magnetometer. The effect of different reaction parameters on the swelling capacity of MSHNs was investigated. Furthermore, batch adsorption experiments of crystal violet dye onto MSHNs were studied by varying solution pH, initial dye concentration, and temperature. Evaluation of thermodynamic parameters of crystal violet adsorption confirmed that the adsorption was spontaneous and endothermic process in nature. The equilibrium study revealed that the dye adsorption behavior of MHSNs followed the Redlich-Peterson isotherm model. Finally, the dye adsorption experiment data was well fitted by the pseudo-second-order kinetic model with the regression coefficient (R2) of 0.9979. Our results suggest that the MHSNs with facile preparation method, high swelling capacity, and high dye adsorption capacity may be used as promising adsorbents for fast removal of various dyes from aqueous solutions. Copyright © 2016 John Wiley & Sons, Ltd.

Characterization and Impact of Newly Synthesized Superabsorbent Hydrogel Nanocomposite on Water Retention Characteristics of Sandy Soil and Grass Seedling Growth

Characterization and Impact of Newly Synthesized Superabsorbent Hydrogel Nanocomposite on Water Retention Characteristics of Sandy Soil and Grass Seedling Growth

Viscoelastic and Rheological Properties of Carboxymethyl Cellulose /Starch/Graphite Oxide as Superabsorbent Hydrogel Nano Composites (SHNCs)

Uncross-linked carboxymethyl cellulose (CMC) / starch blend used to prepare two hydrogels; the first is cross-linked CMC / starch with aluminum sulfate octadecahydrate cross-linker and the second is SHNCs manufactured from incorporation of 0.3wt% nano graphite oxide (GO) in the above cross-linked blend. Viscoelastic and rheological properties of these two hydrogels were studied and compared with the uncross-linked blend. Results showed that the cross-linking process increases the blend miscibility and converted it to miscible blend. The SHNCs hydrogel has the higher Tg and the uncross-linked blend has the higher Tan δ. GO addition causes increment in some viscoelastic parameters such as G*, G', and G, and decrement in damping parameters and make the damping behavior more stable at lower frequencies, and causes increment for all rheological parameters (η* , ηo, ηf , and GNo). GO addition leads, also, to the absence of the shear thickening behavior and increases both the entanglement density and the molecular weight average. Both hydrogels exhibited broad molecular weight distribution (MWD) and highly cross-linking degree and their elastic behavior predominates; makes them rigid specially at higher frequencies.

Synthesis and properties of a novel ecofriendly superabsorbent hydrogel nanocomposite based on xyloglucan-graft-poly(acrylic acid)/diatomite

Recently, there has been growing interest in the use of natural available materials to prepare superabsorbents due to their low-cost and environmental friendliness.

Effects of a Novel Poly (AA-co-AAm)/AlZnFe2O4/potassium Humate Superabsorbent Hydrogel Nanocomposite on Water Retention of Sandy Loam Soil and Wheat Seedling Growth

A novel poly(acrylic acid-co-acrylamide)AlZnFe2O4/potassium humate superabsorbent hydrogel nanocomposite (PHNC) was synthesized and its physical properties characterized using SEM, Energy Dispersive X-ray (EDX) and FTIR spectroscopic techniques. Air dried sandy loam soil was amended with 0.1 to 0.4 w/w% of PHNC to evaluate its soil moisture retention attributes. Effect of PHNC amendment on pH, electrical conductivity (EC), porosity, bulk density and hydraulic conductivity of sandy loam soil was also studied. The soil amendment with 0.1 to 0.4 w/w% of PHNC remarkably enhanced the moisture retention at field capacity as compared to the un-amended soils. Seed germination and seedling growth of wheat (Triticum aestivum L.) was considerably increased and a delay by 6–9 days in wilting of seedlings was observed in the soil amended with PHNC, resulting in improved wheat plant establishment and growth.

Improvement in the Water Retention Characteristics of Sandy Loam Soil Using a Newly Synthesized Poly(acrylamide-co-acrylic Acid)/AlZnFe2O4 Superabsorbent Hydrogel Nanocomposite Material

The use of some novel and efficient crop nutrient-based superabsorbent hydrogel nanocomposites (SHNCs), is currently becoming increasingly important to improve the crop yield and productivity, due to their water retention properties. In the present study a poly(Acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite was synthesized and its physical properties characterized using Energy Dispersive X-ray (EDX), FE-SEM and FTIR spectroscopic techniques. The effects of different levels of SHNC were studied to evaluate the moisture retention properties of sandy loam soil (sand 59%, silt 21%, clay 19%, pH 7.4, EC 1.92 dS/m). The soil amendment with 0.1, 0.2, 0.3 and 0.4 w/w% of SHNC enhanced the moisture retention significantly at field capacity compared to the untreated soil. Besides, in a separate experiment, seed germination and seedling growth of wheat was found to be notably improved with the application of SHNC. A delay in wilting of seedlings by 5–8 days was observed for SHNC-amended soil, thereby improving wheat plant growth and establishment.

Superabsorbent hydrogel nanocomposites based on starch-g-poly(sodium acrylate) matrix filled with cellulose nanowhiskers

Superabsorbents hydrogel nanocomposites based on starch-g-poly(sodium acrylate) and cellulose nanowhiskers (CNWs) were synthesized. A set of experiments was performed to evaluate the influence of some factors such as NaAc/starch mass ratio, crosslinker, and nanowhiskers amount in the swelling capacity and swelling kinetics. Increasing the NaAc/starch mass ratio up to 7 leads to an increase in the water uptake at a maximum value, however, higher ratios decreased that value due to the increase of crosslinking points. Similarly, the incorporation of CNWs up to 10 wt% provided an improvement in the swelling due to the hydrophilic groups from cellobiose units. Further, the incorporation of CNWs diminishes the water uptake. Besides, the CNWs improved the mechanical properties. SEM images showed that CNWs increase the average porous size of composites. The composites presented good responsive behavior in relation to pH and salt presence allowing those materials suitable for many potential applications.

Preparation and swelling properties of graphene oxide/poly(acrylic acid-co-acrylamide) super-absorbent hydrogel nanocomposites

A series of novel graphene oxide (GO)/poly(acrylic acid-co-acrylamide) super-absorbent hydrogel nanocomposites were prepared by in situ radical solution polymerization. The effects of GO content on the chemical structure, morphology and miscibility of the hydrogels were studied. The swelling behaviors, swelling kinetics and pH-responsive behaviors of the hydrogels were also evaluated. Owing to the hydrogen bonds and possible covalent bonds between GO and polymer chains, relatively lower content (<0.30wt%) of GO could be dispersed well in the polymer matrix and enhanced the intermolecular interactions between the components effectively. On the contrary, an excessive amount of GO might form large agglomerates and weakened the interfacial interactions, resulting in the micro-phase separation between the components. Furthermore, the swelling capacities and swelling rates of hydrogels went up with increasing GO loadings to 0.30wt% and then decreased with further increasing GO loadings. It is worth noting that the hydrogel only containing 0.10wt% GO exhibited significant improvement of swelling capacity in neutral medium, and could also retain relatively higher swelling capacities to a certain degree at acidic and basic solutions. Therefore, the as-prepared GO-based super-absorbent hydrogels might have potential applications in many areas, such as biomedical engineering, construction engineering and hygienic products.

Superabsorbent hydrogel composites and nanocomposites: A review

AbstractSuperabsorbent polymers are hydrophilic networks that can absorb and retain huge amounts of water or aqueous solutions. They are currently used in many areas including hygienic and bio‐related uses (particularly in disposable diapers), agricultural uses (e.g., water reserving in soil, soil conditioning, and controlled release of agrochemicals), pharmaceutical dosage forms, separation technology, fibers/textiles, water‐swelling rubbers, soft actuators/valves, electrical, construction, packaging, artificial snow, sludge/coal dewatering, fire‐extinguishing gels, etc. Addition of clays and organo‐modified clays into superabsorbent formulation has funded new generations of these hydrogels, i.e., superabsorbent hydrogel composites (SHCs) and superabsorbent hydrogel nanocomposites (SHNCs). New superabsorbent hydrogels are cheaper in price, and possess superior mechanical properties than non‐composite counterparts. This review introduces the SHC and SHNC polymers with the focus on different minerals and humic additives, synthetic methods, the hydrogel characteristics and their applications. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers