Synthesis Of Superabsorbent Hydrogels Research Articles

Development and validation of LC-MS/MS method for trace analysis of acrylamide, acrylic acid and N, N-methylene bis acrylamide in sandy loam soil

Acrylamide and N, N-methylene bis acrylamide are most commonly used monomer and crosslinker compounds employed in synthesis of super absorbent hydrogels. When applied as soil conditioners, there are apprehensions that these hydrogels degrade over time and thus may release the toxic monomers in the soil. A method was thus developed using Liquid Chromatography tandem mass spectrometry (LC-MS/MS) for the trace level quantification of acrylamide (AD), acrylic acid (AA) and N,N-methylene-bis-acrylamide (MBA) in sandy loam soil amended by two test hydrogels the Pusa Hydrogel and SPG 1118 hydrogel prepared using AD and MBA. The MRM (multiple reaction monitoring) transitions were optimized for both the compounds. Soil samples were extracted using dispersive solid-phase extraction (dSPE) with a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique, employing acetonitrile. All analytes were quantified at trace levels within a five-minute run using UHPLC equipped with a C-18 column.Single laboratory validation of the developed method in soil matrix was conducted based on specificity, linearity, sensitivity, accuracy, precision, matrix effect and measurement of uncertainty. LC-MS/MS exhibited a linear response in the concentration range of 0.001 to 1 µg mL−1, with correlation coefficient >+0.99. Acceptable recovery (within 70–120 %) with repeatability (%RSD ≤20 %) was obtained at 0.01 to 1 µg g–1 fortification levels. LOQ (Limit of quantification) of the method for AD, AA and MBA in soil matrix were 0.05, 1 and 0.01 µg g–1, respectively. Both intra-laboratory repeatability and intermediate precision at LOQ suggested well acceptable precise (HorRat≈ 0.3) method for quantification. Matrix enhancement effect was observed in the order: AA>AD>MBA. The Expanded Uncertainty (EU) in soil matrix at LOQ was 21.64 %, 28 % and 19 % for AD, AA and MBA respectively. Groundnut and wheat grown with application of the hydrogels showed no detectable residues of monomers in soil samples (total n = 60) near the root zone at the time of crop harvesting.

Synthesis of Superabsorbent Hydrogels with Predefined Geometries and Controlled Swelling Properties for Versatile 3D Cell Culture Scaffolds.

This research presents a simple but general method to prepare water-soluble-polymer-based superabsorbent hydrogels with predefined microscale geometries and controlled swelling properties. Unlike conventional hydrogel preparation methods based on bulk solution-phase cross-linking, poly(vinyl alcohol) is homogeneously mixed with polymer-based cross-linkers in the solution phase and thermally cross-linked in the solid phase after drying; the degree of cross-linking is modulated by controlling the cross-linker concentration, pH, and/or thermal annealing conditions. After the shape definition process, cross-linked films or electrospun nanofibers are treated with sulfuric acid to weaken hydrogen bonds and introduce sulfate functionality in polymer crystallites. The resultant superabsorbent hydrogels exhibit an isotropic expansion of the predefined geometry and tunable swelling properties. Particularly, hydrogel microfibers exhibit excellent optical transparency, good biocompatibility, large porosity, and controlled cell adhesion, leading to versatile 3D cell culture scaffolds that not only support immortalized cell lines and primary neurons but also enable stiffness-modulated cell adhesion studies.

Synthesis and assessment of carboxymethyl tamarind kernel gum based novel superabsorbent hydrogels for agricultural applications

The novel superabsorbent hydrogels (SAH) were fabricated by interpenetrating carboxymethyl tamarind kernel gum with sodium-acrylate. The synthesis of SAH was verified by characterization using Fourier-transform infrared spectroscopy, thermo-gravimetric analysis, scanning electron microscopy and swelling studies under various solutions. The hydrogel formed was found out to be degradable (soil burial biodegradation test). Maximum water holding capacity, bulk density, porosity and water retention capacity of soil were evaluated to see the effects on soil by the hydrogel treatment. The hydrogel which absorbs up to 648 ml/g, post inclusion to soil, and showed significant enhancement in the moisture absorption (35%), porosity (7%) and water retension capacity compared to the untreated (control) soil. The effects of the hydrogel were also seen on the growth of chickpea plants. The synthesized SAH displayed promising potential as soil conditioner for agricultural applications.

Radical Copolymerization Kinetics of Bio-Renewable Butyrolactone Monomer in Aqueous Solution

The radical copolymerization kinetics of acrylamide (AM) and the water-soluble monomer sodium 4-hydroxy-4-methyl-2-methylene butanoate (SHMeMB), formed by saponification of the bio-sourced monomer γ-methyl-α-methylene-γ-butyrolactone (MeMBL), are investigated to explain the previously reported slow rates of reaction during synthesis of superabsorbent hydrogels. Limiting conversions were observed to decrease with increased temperature during SHMeMB homopolymerization, suggesting that polymerization rate is limited by depropagation. Comonomer composition drift also increased with temperature, with more AM incorporated into the copolymer due to SHMeMB depropagation. Using previous estimates for the SHMeMB propagation rate coefficient, the conversion profiles were used to estimate rate coefficients for depropagation and termination (kt). The estimate for kt,SHMeMB was found to be of the same order of magnitude as that recently reported for sodium methacrylate, with the averaged copolymerization termination rate coefficient dominated by the presence of SHMeMB in the system. In addition, it was found that depropagation still controlled the SHMeMB polymerization rate at elevated temperatures in the presence of added salt.

Synthesis of superabsorbent hydrogel and manganese dioxide nanowires composite for adsorption of Pb(II) from aqueous solution

The superabsorbent composite was prepared by aqueous solution polymerization, using manganese dioxide, acrylic acid, acrylic amide, 2-acrylamide-2-methyl-1-propanesulfonic acid as raw materials, N,N′-methylene bisacrylamide as cross-linker, and K2S2O8 as initiator. The composite was characterized by Fourier transform infrared spectrophotometer, thermogravimetric analysis and scanning electron microscopy analysis. This article also described the adsorption behavior of the superabsorbent composite with respect to Pb(II) removal from aqueous solution. The kinetic studies for Pb(II) adsorption showed that the pseudo-second-order adsorption mechanism was predominant. Moreover, adsorption isotherm data were reliably described by the Freundlich model. Regeneration of the adsorbent was attained by 0.1 mol L−1 HCl. POLYM. COMPOS., 36:775–784, 2015. © 2014 Society of Plastics Engineers

Synthesis of Super Absorbent Hydrogels with Using Releasing Drug

Synthesis of Super Absorbent Hydrogels with Using Releasing Drug

Pectin-based surperabsorbent hydrogels crosslinked by some chemicals: synthesis and characterization

Synthesis of superabsorbent hydrogels from pectin was investigated using three kinds of crosslinkers, CaCl2, ethylene glycol diglycidyl ether (EGE), and glutaraldehyde (GA). Among them, GA was the most suitable to attain high absorbency, reaching ca. 500 g/g in pure water. On the contrary, hydrogels crosslinked by CaCl2 and EGE absorbed much less water, their maximum absorbency was around 200 g/g and 40 g/g, respectively. Absorbency in 0.9% NaCl solution of hydrogel crosslinked by GA was as low as 15 g/g, which indicates absorbency of hydrogels in the present study is sensitive to salt concentration. Biodegradability of pectin-based hydrogels in activated sludge at 25 °C for 18 days was 60–65%.