Starch-based Hydrogels Research Articles

Triboelectric Self-Powered Wearable Flexible Patch as 3D Motion Control Interface for Robotic Manipulator.

Triboelectric nanogenerators and sensors can be applied as human-machine interfaces to the next generation of intelligent and interactive products, where flexible tactile sensors exhibit great advantages for diversified applications such as robotic control. In this paper, we present a self-powered, flexible, triboelectric sensor (SFTS) patch for finger trajectory sensing and further apply the collected information for robotic control. This innovative sensor consists of flexible and environmentally friendly materials, i. e., starch-based hydrogel, polydimethylsiloxane (PDMS), and silicone rubber. The sensor patch can be divided into a two-dimensional (2D) SFTS for in-plane robotic movement control and a one-dimensional (1D) SFTS for out-of-plane robotic movement control. The 2D-SFTS is designed with a grid structure on top of the sensing surface to track the continuous sliding information on the fingertip, e. g., trajectory, velocity, and acceleration, with four circumjacent starch-based hydrogel PDMS elastomer electrodes. Combining the 2D-SFTS with the 1D-SFTS, three-dimensional (3D) spatial information can be generated and applied to control the 3D motion of a robotic manipulator, and the real-time demonstration is successfully realized. With the facile design and very low-cost materials, the proposed SFTS shows great potential for applications in robotics control, touch screens, and electronic skins.

Starch/graphene hydrogels via click chemistry with relevant electrical and antibacterial properties

Starch-based hydrogels were performed by Diels-Alder cross-linking reactions between furan-modified starch and a water soluble bismaleimide, with improving conducting properties by using graphene layers as active nanofillers. The characterization results demonstrated that the Diels-Alder reaction and the corresponding conditions for the hydrogel formation were appropriate. The effect of increasing the furan/maleimide ratio on the architecture of the hydrogels and on the morphological, rheological and swelling properties were thoroughly evaluated. Effective network structure was obtained by increasing the cross-linker content leading to decreasing pore size and increasing storage modulus value of the final material. It was shown that the swelling behavior of hydrogels was mainly governed by the hydrophilic character of bismaleimide. Graphene nanosheets were added for the synthesis of nanocomposite hydrogel and it was characterized in terms of rheological properties, electrical conductivity and antimicrobial activity. The nanocomposite hydrogel presented enhanced mechanical performance, antimicrobial activity and increased conductivity values, up to a decade, indicating that conductive and active hydrogels could be satisfactory obtained, for a large range of potential applications such as biomed.

Starch-based semi-IPN hydrogel nanocomposite integrated with clinoptilolite: Preparation and swelling kinetic study

Semi-interpenetrating polymer network (semi-IPN) of starch-graft-poly(acrylic acid-co-acrylamide)/polyvinyl alcohol/clinoptilolite (starch-g-p(AA-co-AAm)/PVA/clino) superabsorbent nanocomposite was synthesized by free-radical graft co-polymerization technique in an aqueous solution. Taguchi method was used to optimize the synthesis reaction condition based on the equilibrium swelling capacity of the hydrogels. FTIR, XRD, and SEM analyses were used to study the chemical and structural properties of the hydrogel samples. The equilibrium swelling capacity of the semi-IPN superabsorbent nanocomposite (364.82 g/g) was higher than that of neat hydrogel (286.21 g/g) and in both of them water penetration into hydrogel network occurred through non-Fickian diffusion mechanism. Incorporation of clino into the polymeric matrix not only increased the equilibrium swelling capacity of the hydrogel, but also induced a substantial enhancement in its mechanical strength. Semi-IPN superabsorbent nanocomposite showed reasonable water absorbency under different loads, good salt and pH-sensitive swelling behavior, and better water retention capability, which make it potentially useful for hygiene products.

Facile preparation and dual responsive behaviors of starch-based hydrogel containing azo and carboxylic groups

Starch-based hydrogel containing azo group (SHA) was prepared through radical cross-linking reaction among starch- and PVA-based macromonomers, acrylic acid (AA) and 4-acryloyoxyazobenzene (AHAB). AHAB was prepared through an acylation reaction between acryloyl chloride and 4-hydroxyazobenzene (p-HAB), which was obtained by the diazo coupling reaction between aniline and phenol. The structure of SHA was confirmed with Fourier transform infrared spectrometer, thermogravimetric analysis and UV–Visible spectroscopy. SHA displayed pH-sensitive swelling in buffer saline. SHA film also exhibited a reversible trans-cis-trans photoisomerization behavior when they were subjected to alternative UV and visible light irradiation or dark storage. The dual-responsive characteristic was easily to be tailored via varying the initial amount of AHAB or AA.

Release of Sodium Salicylate from Hydrogels Prepared from Wheat and Arrowroot Starches

Sodium salicylate (SS), a non-steroidal anti-inflammatory drug, was loaded into starch-based hydrogels and the release characteristics of SS therefrom was studied. The hydrogels were prepared from wheat and arrowroot starches and crosslinked with either glutaraldehyde or sodium tetraborate decahydrate (borax). SS was loaded into hydrogel at concentrations of 10 and 20%w/w based on dry weight of sample. The study of release characteristics was carried out by total immersion method for 24 h in an acetate buffer solution (pH 5.5) at 32°C as the same condition of human skin. A burst release of SS at the initial time followed by a gradual release to reach a plateau was observed. The maximum amounts of SS released from the hydrogels were about 8-22 mg. The amount of water retention of hydrogels was also determined at the same condition with that of the study of release. The hydrogels with the greater amount of water retention showed the higher release of SS. The hydrogels crosslinked with borax had higher amounts of SS released than those crosslinked with glutaraldehyde. The hydrogels containing 20% SS-loaded showed higher amounts of SS released than those containing 10% SS-loaded. The hydrogels prepared from arrowroot starch showed higher amounts of SS released than those prepared from wheat starch. From the study of release kinetics based on the Korsmeyer-Peppas model, the exponents of release (n) of all specimens were close to 1 which indicated Case II diffusion.

Multiple stimuli-responsive selenium-functionalized biodegradable starch-based hydrogels.

Novel biodegradable diselenide cross-linked starch-based hydrogels were synthesized via free radical copolymerization, which serve as stimuli-responsive drug release materials composed of starch chain backbones with an enzyme hydrolysis property and selenium-containing cross-linkers with a redox responsive cleavage property. Rhodamine B (RB) loaded starch-based hydrogels were prepared in order to investigate their stimuli-responsive release behaviours. In the presence of external redox agents, the enzyme stimuli as well as the mixture of the above stimuli, the prepared starch-based hydrogels exhibit controlled multi-responsive release behavior of RB. Overall, the merits of good biodegradation and multi-stimuli responsiveness make these kinds of starch-based hydrogels promising biomedical candidates for the realization of controlled drug delivery.

Zwitterionic starch-based hydrogel for the expansion and “stemness” maintenance of brown adipose derived stem cells

Brown adipose derived stem cells (BADSCs) have become a promising stem cell treatment candidate for myocardial infarction because of their efficiently spontaneous differentiation capacity towards cardiomyocytes. The lack of existing cell passage protocols motivates us to develop a neotype 3D cell expansion technique for BADSCs. In this study, “clickable” zwitterionic starch based hydrogels are developed using methacrylate modified sulfobetaine derived starch with dithiol-functionalized poly (ethylene glycol) as crosslinker via the “thiol-ene” Michael addition reaction. Moreover, CGRGDS peptide is immobilized into the hydrogel via a similar “clickable” approach. Their Young's moduli range from 22.28 to 74.81 kPa depending on the concentration of precursor solutions. Excellent anti-fouling property is also presented owing to the introduction of zwitterionic moieties. BADSCs are homogeneously encapsulated in the hydrogels and then routinely cultured for 10 days. Results suggest a capacious cell proliferation and the extent increases with either the decrease of mechanical strength or the introduction of CGRGDS. More excitingly, the cell “stemness” is well maintained during this period and the expanded cells released from the hydrogels well keep the efficiently spontaneous cardiomyogenic differentiation capacity. Therefore, it is suggested that zwitterionic starch based hydrogel is able for the expansion and “stemness ” maintenance of BADSCs.

Modified Dioscorea hispida starch-based hydrogels and their in-vitro cytotoxicity study on small intestine cell line (FHS-74 Int)

Starch-based hydrogels are promising smart materials for biomedical and pharmaceutical applications, which offer exciting perspectives in biophysical research at molecular level. This work was intended to develop, characterize and explore the properties of hydrogel from starch extracted from new source, Dioscorea hispida Dennst. Starch-mediated hydrogels were successfully synthesized via free radical polymerization method with varying concentrations of acrylic acid (AA),N,N’-methylenebisacrylamide (MBA) and sodium hydroxide (NaOH) in aqueous system. The grafting reaction between starch and AA was examined by observing the decline in intensity peak of hydrogel FTIR spectrum at 3291cm−1 and peak around 1600–1680cm−1, indicating the stretching of hydroxyl group (OH) and stretching of carbon–carbon double bond (CC) respectively. The effects of cross-linker, monomer and NaOH concentration on swelling ratio and gel content in different medium and conditions were also evaluated. The thermal stability and structural morphology of as-synthesized hydrogels were studied by thermogravimetry analysis (TGA) and scanning electron microscopy (SEM). In-vitro cytotoxicity study using small intestine cell line (FHS-74 Int) revealed that the as-formulated eco-friendly-hydrogel was free from any harmful material and safe to use for future product development.

Cell viability and hemocompatibility evaluation of a starch-based hydrogel loaded with hydroxyapatite or calcium carbonate for maxillofacial bone regeneration.

The objective of this study is to evaluate the cell viability and hemocompatibility of starch-based hydrogels for maxillofacial bone regeneration. Seven starch-based hydrogels were prepared: three loaded with 0.5, 1 and 2% calcium carbonate (Sigma Aldrich, St. Louis, MO, USA); three loaded with 2, 3 and 4% hydroxyapatite (Sigma Aldrich); and one not loaded as a control. A 10M NaOH was then added to induce hydrogel formation. Human osteoblasts were cultured on each hydrogel for 72h. An MTS assay (Cell Titer96; PROMEGA, Madison, WI, USA) was used to assess cell viability. Hemocompatibility testing was conducted with normal human blood in the following conditions: 100mg of each hydrogel in contact with 900µL of whole blood for 15min at 37°C under lateral stirring. Higher percentages of cell viability were observed in starch-based hydrogels loaded with hydroxyapatite as compared with the control. The hemolysis test showed a hemolysis level lower than 2%. Activated partial thromboplastin time and prothrombin time were unchanged, while platelet counting showed a slight decrease when compared with controls.

Characteristic of Starch-Poly(N-Vinyl-Pyrrolidone) for an encapsulation material in floating drug delivery system

Modified starch has been widely used in many studies in the field of drug delivery for gastrointestinal drug release. In this study, the starch was modified with poly(N-vinyl-pyrrolidone) by interpenetrating polymer network (IPN) method. Characterizations were done to observe its characteristics in floating drug delivery applications. Three modified starch-based hydrogels were synthesized, i.e. crosslinked starch, semi-IPN, and full-IPN hydrogels. Non-modified starch hydrogel was also synthesized for benchmark purpose. All materials were characterized and analysed by Swelling Test, Buoyancy Test, Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR). Swelling test showed that the crosslinked-starch hydrogel has the lowest swelling percentage compared to other hydrogels, whereas non-modified hydrogels tend to have similar swelling percentage to Semi-IPN. Morphology and visual analysis results showed that non-modified hydrogels were physically the most fragile, followed by a crosslinked-starch, semi-IPN-starch, and full-IPN-starch hydrogel. Therefore, full-IPN-starch hydrogel had the highest elasticity. From IR spectrum result, it can be seen that a wavenumbers shift was observed for the modified starch compared with the IR spectrum of pure starch powder. TGA and DSC characterizations showed the degradation temperature for non-modified hydrogel was at 250°C. The degradation temperature for both crosslinked and semi-IPN starch were at 275°C. For full-IPN, however, the degradation temperature was at 225°C. On the other hand, the degradation level could be observed from DSC and TGA results as well. Full-IPN appeared to be the slowest, while non-modified hydrogel seem to be the fastest to degrade. CaCO3 was used as the pore forming agent (PFA) in this research for buoyancy characterization. Buoyancy test showed that the full-IPN had the fastest floating lag and longest floating time followed by semi-IPN-starch, crosslinked-starch, and non-modified starch. From all characterizations done in this research, it can be suggested that the full-IPN provided the most suitable characteristics as an encapsulation material candidate in a floating drug delivery system.

Gelatin- and starch-based hydrogels. Part B: In vitro mesenchymal stem cell behavior on the hydrogels

Tissue regeneration often occurs only to a limited extent. By providing a three-dimensional matrix serving as a surrogate extracellular matrix that promotes adult stem cell adhesion, proliferation and differentiation, scaffold-guided tissue regeneration aims at overcoming this limitation. In this study, we applied hydrogels made from crosslinkable gelatin, the hydrolyzed form of collagen, and functionalized starch which were characterized in depth and optimized as described in Van Nieuwenhove et al., 2016. “Gelatin- and Starch-Based Hydrogels. Part A: Hydrogel Development, Characterization and Coating”, Carbohydrate Polymers 152:129–39. Collagen is the main structural protein in animal connective tissue and the most abundant protein in mammals. Starch is a carbohydrate consisting of a mixture of amylose and amylopectin. Hydrogels were developed with varying chemical composition (ratio of starch to gelatin applied) and different degrees of methacrylation of the applied gelatin phase. The hydrogels used exhibited no adverse effect on viability of the stem cells cultured on them. Moreover, initial cell adhesion did not differ significantly between them, while the strongest proliferation was observed on the hydrogel with the highest degree of cross-linking. On the least crosslinked and thus most flexible hydrogels, the highest degree of adipogenic differentiation was found, while osteogenic differentiation was the strongest on the most rigid, starch-blended hydrogels. Hydrogel coating with extracellular matrix compounds aggrecan or fibronectin prior to cell seeding exhibited no significant effects. Thus, gelatin-based hydrogels can be optimized regarding maximum promotion of either adipogenic or osteogenic stem cell differentiation in vitro, which makes them promising candidates for in vivo evaluation in clinical studies aiming at either soft or hard tissue regeneration.

Effects of nanozeolite/starch thermoplastic hydrogels on wound healing.

Background:Wound healing is a complex biological process. Some injuries lead to chronic nonhealing ulcers, and healing process is a challenge to both the patient and the medical team. We still look forward an appropriate wound dressing.Materials and Methods:In this study, starch-based nanocomposite hydrogel scaffolds reinforced by zeolite nanoparticles (nZ) were prepared for wound dressing. In addition, a herbal drug (chamomile extract) was added into the matrix to accelerate healing process. To estimate the cytocompatibility of hydrogel dressings, fibroblast mouse cells (L929) were cultured on scaffolds. Then, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium-bromide assay test and interaction of cells and scaffolds were evaluated. For evaluating healing process, 48 male rats were randomly divided into four groups of four animals each (16 rats at each step). The ulcers of the first group were treated with the same size of pure hydrogels. The second group received a bandage with the same size of hydrogel/extract/4 wt% nZ (hydrogel NZE). The third group was treated with chamomile extract, and the fourth group was considered as control without taking any medicament. Finally, the dressings were applied on the chronic refractory ulcers of five patients.Results:After successful surface morphology and cytocompatibility tests, the animal study was carried out. There was a significant difference between starch/extract/4 wt% nZ and other groups on wound size decrement after day 7 (P < 0.05). At the clinical pilot study step, the refractory ulcers of all five patients were healed without any hypersensitivity reaction.Conclusion:Starch-based hydrogel/zeolite dressings may be safe and effective for chronic refractory ulcers.

Gelatin- and starch-based hydrogels. Part A: Hydrogel development, characterization and coating

The present work aims at constructing the ideal scaffold matrix of which the physico-chemical properties can be altered according to the targeted tissue regeneration application. Ideally, this scaffold should resemble the natural extracellular matrix (ECM) as close as possible both in terms of chemical composition and mechanical properties. Therefore, hydrogel films were developed consisting of methacrylamide-modified gelatin and starch-pentenoate building blocks because the ECM can be considered as a crosslinked hydrogel network consisting of both polysaccharides and structural, signaling and cell-adhesive proteins. For the gelatin hydrogels, three different substitution degrees were evaluated including 31%, 72% and 95%. A substitution degree of 32% was applied for the starch-pentenoate building block. Pure gelatin hydrogels films as well as interpenetrating networks with gelatin and starch were developed. Subsequently, these films were characterized using gel fraction and swelling experiments, high resolution-magic angle spinning 1H NMR spectroscopy, rheology, infrared mapping and atomic force microscopy. The results indicate that both the mechanical properties and the swelling extent of the developed hydrogel films can be controlled by varying the chemical composition and the degree of substitution of the methacrylamide-modified gelatin applied. The storage moduli of the developed materials ranged between 14 and 63kPa. Phase separation was observed for the IPNs for which separated starch domains could be distinguished located in the surrounding gelatin matrix. Furthermore, we evaluated the affinity of aggrecan for gelatin by atomic force microscopy and radiolabeling experiments. We found that aggrecan can be applied as a bioactive coating for gelatin hydrogels by a straightforward physisorption procedure. Thus, we achieved distinct fine-tuning of the physico-chemical properties of these hydrogels which render them promising candidates for tissue engineering approaches.

Antimicrobial Activity of Starch Hydrogel Incorporated with Copper Nanoparticles.

In order to obtain an antimicrobial gel, a starch-based hydrogel reinforced with silica-coated copper nanoparticles (Cu NPs) was developed. Cu NPs were synthesized by use of a copper salt and hydrazine as a reducing agent. In order to enhance Cu NP stability over time, they were synthesized in a starch medium followed by a silica coating. The starch hydrogel was prepared by use of urea and water as plasticizers and it was treated with different concentrations of silica-coated copper nanoparticles (Si-Cu NPs). The obtained materials were characterized by Fourier transform infrared (FT-IR) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, scanning electron microscopy (SEM), and rheometry. FT-IR and EPR spectra were used for characterization of Cu NPs and Si-Cu NPs, confirming that a starch cap was formed around the Cu NP and demonstrating the stability of the copper nanoparticle after the silica coating step. SEM images showed Cu NP, Si-Cu NP, and hydrogel morphology. The particle size was polydisperse and the structure of the gels changed along with particle concentration. Increased NP content led to larger pores in starch structure. These results were in accordance with the rheological behavior, where reinforcement by the Si-Cu NP was seen. Antimicrobial activity was evaluated against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial species. The hydrogels were demonstrated to maintain antimicrobial activity for at least four cycles of use. A dermal acute toxicity test showed that the material could be scored as slightly irritant, proving its biocompatibility. With these advantages, it is believed that the designed Si-Cu NP loaded hydrogel may show high potential for applications in various clinical fields, such as wound dressings and fillers.

Physical Cross-Linking Starch-Based Zwitterionic Hydrogel Exhibiting Excellent Biocompatibility, Protein Resistance, and Biodegradability

In this work, a novel starch-based zwitterionic copolymer, starch-graft-poly(sulfobetaine methacrylate) (ST-g-PSBMA), was synthesized via Atom Transfer Radical Polymerization. Starch, which formed the main chain, can be degraded completely in vivo, and the pendent segments of PSBMA endowed the copolymer with excellent protein resistance properties. This ST-g-PSBMA copolymer could self-assemble into a physical hydrogel in normal saline, and studies of the formation mechanism indicated that the generation of the physical hydrogel was driven by electrostatic interactions between PSBMA segments. The obtained hydrogels were subjected to detailed analysis by scanning electron microscopy, swelling ratio, protein resistance, and rheology tests. Toxicity and hemolysis analysis demonstrated that the ST-g-PSBMA hydrogels possess excellent biocompatibility and hemocompatibility. Moreover, the cytokine secretion assays (IL-6, TNF-α, and NO) confirmed that ST-g-PSBMA hydrogels had low potential to trigger the activation of macrophages and were suitable for in vivo biomedical applications. On the basis of these in vitro results, the ST-g-PSBMA hydrogels were implanted in SD rats. The tissue responses to hydrogel implantation and the hydrogel degradation in vivo were determined by histological analysis (Hematoxylin and eosin, Van Gieson, and Masson's Trichrome stains). The results presented in this study demonstrate that the physical cross-linking, starch-based zwitterionic hydrogels possess excellent protein resistance, low macrophage-activation properties, and good biocompatibility, and they are a promising candidate for an in vivo biomedical application platform.

Multi-responsive hydrogel based on lotus root starch

The lotus root starch-based hydrogel was synthesized by free radical copolymerization. Fourier Transform Infrared Spectroscopy (FTIR) demonstrated that the formation of target product. X-ray diffraction (XRD) analysis showed the change of the starch’s crystallization. The morphology and pore structure of the hydrogel were evaluated by Field Emission Scanning Electron Microscope (FESEM) and Biomicroscope. Thermogravimetric analysis revealed the better thermal stability of hydrogel. Furthermore, the swelling in CaCl2 and AlCl3 solutions/temperature (25°C–65°C) displayed the “overshooting effect” swelling-deswelling phenomenon with prolonging the swelling time. The hydrogel can rapidly response to various pH value as well.

An In-depth Analysis of the Mechanical, Electrical, and Drug Release Properties of Gelatin–Starch Phase-Separated Hydrogels

ABSTRACTGelatin–starch-based phase-separated hydrogels were prepared in this study. Corn starch, soluble starch, and hydrated starch were used as the representative starches for the preparation of the hydrogels. Bright field microscopy suggested the formation of phase-separated hydrogels. An increase in the hydrophilic nature of the starch molecules resulted in decrease in the agglomeration of the starch particles within the gelatin matrices. Fourier transform infrared study confirmed the presence of starch particles within the hydrogels. X-ray diffraction studies suggested that the higher degree of crystallinity of corn starch and soluble starch was responsible for the comparative hydrophobic nature of these starch particles. Hydrated starch was found to be amorphous in nature and can be explained by the destruction of the intramolecular associative forces. Stress relaxation and creep recovery studies indicated predominant elastic nature of the hydrogels. Hydrated starch-containing hydrogels were firmer than corn starch and soluble starch because of the better miscibility of the hydrated starch particles within the gelatin matrices. The bulk resistance of the starch-containing hydrogels was higher. This was because of the capability of the starch particles to behave as dielectric medium. Incorporation of starch particles within the gelatin matrix was found to increase the polymer relaxation-mediated drug diffusion. Metronidazole-loaded hydrogels were found to have good antimicrobial activity.

Novel Dioscorea hispida starch-based hydrogels and their beneficial use as disinfectants

Starch-grafted polyacrylamide hydrogels were successfully prepared via chemical polymerization method in basic solution, which provides a homogeneous suspension in the reaction system. The results obtained from Fourier transform infrared–attenuated total reflectance confirmed that the monomer polyacrylamide was grafted onto the starch backbone as shown by the cross-linked peak at 1638 cm−1. Scanning electron microscopy showed that the morphology of starch-grafted polyacrylamide hydrogels has a highly porous structure which provides excellent water absorption capacity with a swelling ratio up to 124%. The X-ray diffraction showed no significant crystallization peaks, indicating that an amorphous hydrogel has been produced. Supported by differential scanning calorimetry, the highest transition glass temperature was observed at 101°C. The starch-grafted polyacrylamide hydrogel extracts inhibited Escherichia coli, Staphylococcus aureus, Saccharomyces cerevisiae, and Salmonella typhimurium growth The fish embryo toxicity test demonstrated that the hydrogel with 2:1 ratio of polyacrylamide: starch has an acceptable level of toxicity. This result indicates that the synthesized hydrogel is applicable for biological purposes with further modifications.

Starch-based hydrogel loading with carbendazim for controlled-release and water absorption

Starch, with properties of eco-friendliness and abundance, is one of the most important natural polymers. Starch-based hydrogels were investigated as carriers of carbendazim to combine controlled-release and water absorption (WA). Three carbendazim-loaded hydrogels (CLHs) with different WA capacities were prepared by solution polymerization. The CLHs were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and liquid-chromatography mass-spectrometry (LC–MS/MS). Release kinetics of CLHs was investigated using 14C-labeling method. The diffusion parameters of CLHs were 0.47, 0.57 and 0.81 in deionized H2O (ddH2O). WA affected release profile significantly, the release longevity reaching 240h when WA was 800g/g in ddH2O. Solution pH influenced release profiles and the lowest release rate occurred in the lowest pH. Addition of CLH (1.3g/kg soil) markedly increased water-holding capacity (WHC) of soil by 8.2%. The study indicated that starch-based CLH was a good controlled-release agent for carbendazim and water absorbent for soil.

Fabrication, characterization and statistical investigation of a new starch-based hydrogel nanocomposite for ammonium adsorption

This work investigates a new starch-based hydrogel nanocomposite made from starch and poly vinyl alcohol blend as polymeric matrix and fumarate-alumoxane (Fum-A) and maleic anhydride (MA) as cross-linking agents, for its use in NH4+ removal from aqueous solutions.The adsorption performance of the hydrogel nanocomposite and also, nanocomposite's maximum adsorption capacity for ammonium adsorption via isotherm studies are examined. Box–Behnken experimental design is used to evaluate performance of hydrogel nanocomposite in the adsorption process. A mechanism was proposed for the chemisorption of ammonia. The water adsorption degree of cross-linked hydrogel nanocomposites decreased with increasing the amount of nanoparticles. The swelling degree of hydrogel nanocomposite (3.6 wt%) was improved about 1.5 units as compared with the hydrogel alone. The maximum removal efficiency (R%) of ammonium ion by hydrogel nanocomposite was 97.99%. The Langmuir isotherm model agrees well with the experimental data and its correlation coefficient value was close to adjust the correlation coefficient value, as compared with Temkin and Freundlich isotherm models. The maximum capacity of the model being 19.01 mg/g was improved compared with the maximum capacity of the Langmuir isotherm (7.43 mg/g).