Methylene Bisacrylamide Research Articles

Removal of Methylene Blue Dye from Aqueous Solutions by Pullulan Polysaccharide/Polyacrylamide/Activated Carbon Complex Hydrogel Adsorption.

In this study, composite hydrogels were prepared using a simple synthetic technique to adsorb methylene blue (MB) from water. The hydrogel comprised potassium persulfate (KPS) as the initiator, N,N'-methylene bisacrylamide as the crosslinking agent, and sodium hydroxide (NaOH) as the activator. It was employed to adsorb MB at different concentrations from water. The morphology and properties of PUL/PAM/GO composites were characterized through thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. Moreover, the adsorption properties, adsorption isotherms, adsorption kinetics, adsorption thermodynamics, and swelling properties of the hydrogel for MB were investigated. The optimal ratio of PUL to AC was obtained as 6:1 by fixing the amount of PUL and loading AC of different masses. The maximum adsorption capacity was obtained as 591.4 mg/g. It also exhibited certain mechanical strength. The adsorption of MB conforms to pseudo-first-order kinetics and Langmuir isotherms. In this study, an environment-friendly, cheap, simple, and efficient way was presented for the composite hydrogel in the direction of water treatment.

Study on dust pollution law and chemical dust suppression technology of non hard pavement in urban construction sites

Dust pollution has been a serious problem for the construction industry. Wind currents inevitably kick up dust on the ground during construction. Dust will not only affect the physical and mental health of construction workers, but also pollute the environment. In this paper, the law of dust generation and diffusion in typical construction sites is simulated and analyzed. According to the simulation, the wind flow lasts for 5s–10s, and the dust concentration in the air reaches more than 50 mg/m3 in the daily environment. In order to control dust pollution, a kind of "green environmental protection" dust suppressor suitable for construction site was developed by using grafting polymerization technology in molecular modification technology. By means of performance characterization, the synthetic ingredients of dust suppressor were determined as 2.5g sodium alginate, 5g acrylamide, 0.15 g N,N ′-methylene bisacrylamide, and the mass ratio of ammonium persulfate to acrylamide was 3%. The optimum temperature for synthesis of dust suppressor was 60 °C. The synthesized dust suppressor can still retain more than 80% moisture after 90min of oven drying at 45 °C, which indicates that the water retention is good. Under the ambient wind speed of 12 m/s, the wind erosion resistance rate is above 99%, which indicates that it has fine anti-wind erosion performance. According to the results of dust suppression experiment, the synthesized dust suppression agent can control the dust in the construction site well.

A cellulose/bentonite grafted polyacrylic acid hydrogel for highly-efficient removal of Cd(II)

In order to remove Cd(II) from waste water, a highly-effective hydrogel named microcrystalline cellulose/bentonite grafted polyacrylic acid (MCC/Ben-g-PAA) was synthesized using microcrystalline cellulose (MCC) and bentonite (Ben) as raw materials with ammonium persulfate (APS) as the initiators and N, N′-Methylene bisacrylamide (MBA) acting as the crosslinker. The adsorbent was characterized by SEM, FTIR, XPS, TG and the results showed that the MCC/Ben-g-PAA contains abundant C and O-containing surface groups, which are favorable for the adsorption of Cd(II). Batch experiments showed that the adsorption of Cd(II) could reach a peak of 242.53 mg/g under the optimal conditions, with the dosage of 1 g/L at pH 6 and the Cd(II) initial concentration of 50–800 mg/L. The adsorption kinetics fitted the pseudo-second order dynamics, and the adsorption isotherm followed the Freundlich model, indicating that the Cd(II) adsorption by MCC/Ben-g-PAA was a chemisorption-based multi-layer process, mainly controlled by intraparticle diffusion. Ion-competition experiments showed that the adsorbent was highly selective with removal rates higher than 95 % for Cd(II) in presence of various cations and anions. Regeneration experiment showed that the adsorbent maintained a Cd(II) removal rate of 88.37 % after 10 cycles. Therefore, the MCC/Ben-g-PAA is an easily-prepared, remarkably-effective and highly-reusable adsorbent, which is rather promising for the treatment of heavy metal-containing wastewater.

Jute Fiber Reinforced Hydrogel Composite for Removal of Methylene Blue Dye from Water

In this study, a hydrogel composite based on natural jute fiber (JF) has been prepared and employed for the removal of methylene blue (MB) dye from aqueous solution. Polyacrylamide (PAAm) hydrogel was synthesized by thermal polymerization in presence of N,N□-methylene bisacrylamide (MBAA) as the cross-linker and potassium per sulfate (KPS) as the initiator. JF reinforced hydrogel (JFRH) composite was prepared by incorporating JF into PAAm matrix prior to the polymerization. The prepared JFRH was characterized by FTIR spectroscopy and scanning electron microscope. It was found that, JFRH composite demonstrated strong mechanical properties with a compressive strength of 1.5 MPa at a deformation of above 80%. The prepared JFRH composite can remove more than 90% of MB from an aqueous solution and be separated easily from the solution after the adsorption process. Therefore, the synthesized JF based hydrogel composite could significantly expand the use of our natural golden fiber for reinforcement of composite materials and removal of dyes from water bodies. Dhaka Univ. J. Sci. 70(2): 59-64, 2022 (July)

Thermal management system study of flame retardant solid–solid phase change material battery

The maximum temperature, temperature homogeneity and flame retardancy of the battery module are crucial to its safe and stable operation. In this paper, a new flame retardant solid–solid phase change material is successfully prepared for the battery thermal management system. Firstly, a new solid-solid phase change material was prepared by using polyethylene glycol (PEG) as the phase change matrix and N,N'-Methylenebisacrylamide (MBA) as the cross-linking agent. Next, a flame retardant material with high thermal conductivity was prepared using microcapsule-coated ammonium polyphosphate (MFAPP) as a flame retardant, expanded graphite (EG) as a thermal conductivity additive and expanded carbon source. The experimental results show that the composite phase change material with 19% MFAPP can provide good thermomechanical properties while having excellent flame-retardant properties. Its Limiting oxygen index (LOI) can reach 32.6 and pass the vertical combustion V-0 grade test. It also maintains good shape stability when heated at 250 °C for 30 min. In addition, the charging and discharging the battery module using CPCM as the heat dissipation medium and air cooling is compared. The results show the maximum temperature of the module is 18.83 °C lower at 2C discharge rate and the maximum temperature difference of the cycle is 7.511 °C lower.

Adsorption and photocatalytic degradation of tetracycline from water by kappa‐carrageenan and iron oxide nanoparticle‐filled poly (acrylonitrile‐co‐N‐vinyl pyrrolidone) composite gel

AbstractIron oxide nanoparticles (FeNPs) based magnetic hydrogels were prepared by in‐situ co‐precipitation of ferric/ferrous salts during copolymerization of acrylonitrile (AN) and N‐vinyl‐2‐pyrrolidone (NVP) at different molar ratios by emulsion polymerization in the presence of different wt% of kappa‐carrageenan (KC) and N, N′‐methylenebisacrylamide (MBA)crosslinker. The hydrogels were characterized by FTIR, proton and13C‐NMR, XPS, XRD, DTA‐TGA, DLS, VSM, UV–Visible spectroscopy, TEM, EDX, PZC, compressive strength and contact angle measurement. The network parameters of the gel networks were determined from equilibrium swelling using Flory and Rehner model. The nanocomposite gels were used for batch and column adsorption of tetracycline (TC) from water. After repeated adsorptions, the TC‐loaded gels were further used for their photocatalytic degradation for safe removal. The NPs‐loaded nanocomposite prepared with 5:1 AN:NVP molar ratio, 1 wt% initiator, 1 wt% MBA and 2 wt% KC showed a rejection of 90.2% and an equilibrium adsorption capacity of 38.9 mg/g for continuous adsorption of 50 mg/L TCs in water in a fixed bed of height 25 mm for an inflow rate of 20 ml/min and the same TC‐loaded composite showed a photo‐degradation efficiency of 86.1% in 2 h.

Fabrication and characterization of a gum ghatti-cl-poly(N-isopropyl acrylamide-co-acrylic acid)/CoFe2O4 nanocomposite hydrogel for metformin hydrochloride drug removal from aqueous solution

Hydrogels are desirable biomaterials because of their innovative organization structure, which allows them to function with a wide range of hydrophilicity and biocompatibility. Hydrogels, on the other hand, possess sensitive physical characteristics when coupled with live tissue. In the current work, metformin hydrogen chloride (metformin HCl)- loaded the original [Gum ghatti-cl-Poly(N-isopropyl acrylamide-co-acrylic corrosive)/CoFe2O4] nanocomposite hydrogel were orchestrated through the free extreme polymerization strategy utilizing ammonium persulfate (APS) as initiator and N, N′-methylene bis-acrylamide (MBA) as a cross-connecting specialist to eliminate the metformin hydrochloride drug from watery arrangements. The influence of numerous parameters on the amount of adsorbate, including pH, temperature, equilibrium time, and adsorbate weight, was investigated, and the ideal conditions for preparing adsorbate were determined. The hydrogel was characterized using FTIR, XRD, AFM, FESEM, and TGA methods. Three powerful models viz. pseudo-first order, pseudo-second order, and intraparticle scattering model, were used and fitted to the equilibrium data to choose the adsorption part of metformin adsorption onto Gg-cl-poly(NIPA-co-AA)/CoFe2O4 nanocomposite hydrogel. The adsorption isotherm information was explored with the assistance of four isotherm models viz. Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DRK) isotherms. The metformin adsorption process followed the pseudo-second-order model and Langmuir adsorption isotherm with a most extreme adsorption limit of 151.07 ​mg/g. To investigate the adsorption nature and promptness metformin, a couple of thermodynamic limits were estimated and observed that the adsorption system is exothermic and unconstrained.

High-efficacy antimicrobial acyclic N-halamine-grafted polyvinyl alcohol film.

With N,N'-methylenebisacrylamide (MBA) and polyvinyl alcohol (PVA) as raw materials, a polymer (PVA-MBA) containing N-halamine precursor functional groups was obtained via grafting reaction between the active hydroxyl groups on PVA and α, β-unsaturated functional groups of MBA under the catalysis of sodium carbonate in an aqueous solution. An acyclic N-halamine precursor-grafted PVA (MBA-PVA) film was formed by simply spreading PVA-MBA aqueous solution in a glass dish and drying it. An antimicrobial acyclic N-halamine-grafted PVA (PVA-MBA-Cl) film was achieved by spraying the diluted sodium hypochlorite solution onto the surface of PVA-MBA film. The performance test of PVA-MBA-Cl film under the optimal preparation conditions showed that the tensile performance and the hydrophobicity were improved, compared to the PVA film. The storage stability test indicated that the oxidative chlorine content Cl+ (atoms/cm2) of the as-prepared PVA-MBA-Cl film only reduced by 14.3% after storage for 9weeks, showing that the antibacterial N-halamine functional groups in PVA-MBA-Cl film has excellent storage stability under room temperature. Antibacterial test showed that the PVA-MBA-Cl film had very strong antibacterial efficacies and could completely kill 1.28 × 106CFU/mL S. aureus and 1.89 × 106CFU/mL E. coli within 1min. Therefore, PVA-MBA-Cl film will have more potential applications in food package.

Cross-linking of polyvinyl alcohol-g-methionine with bisacrylamide and optimization of its swelling response using taguchi method

A hydrophilic macromolecular network is synthesized by crosslinking of grafted polyvinyl alcohol methionine with bisacrylamide (PVAMB). Firstly, polyvinyl alcohol (PVA) was chemically modified by grafting methionine onto its backbone using persulphate initiator. Secondly, the crosslinking of grafted polymer was carried out using N, N’ - Methylene bisacrylamide. The crosslinked macromolecule was characterized by UV Visible spectroscopy, FTIR spectroscopy, X-ray diffraction. The thermal behaviour of the crosslinked polymer was analysed using thermogravimetric analyser. The thermal stability of the polymeric network was found to be stable up to 400 °C. To optimize the performance and quality of the synthesized cross-linked polymer, Taguchi L-9 orthogonal array of experiments were designed with the factors such as weight of the hydrogel, pH, time of exposure and temperature using Qualitek-4 software. The studies revealed that PVAMB retains water molecules in their network to a greater extent in neutral solution. Also the swelling behaviour of the cross-linked polymer was investigated in various physiological solutions.

Comparison of hydrogel- and xerogel-based sorbent from Empty Fruit Bunch (EFB)

This paper focuses on the synthesis and comparison of hydrogel- and xerogel-based sorbents from EFB.Hydrogels were synthesised by polymerisation of EFB biochar with acrylamide (AAm) as a monomer, N, N'-Methylenebisacrylamide (MBA) as cross-linker and ammonium persulfate (APS) as initiator, as well as by internal gelation method of sodium alginate, empty fruit bunch (EFB), calcium carbonate (CaCO3), and glucono delta-lactone (GDL). From the alginate hydrogels obtained, xerogels were synthesised via the oven-drying method. Then, EFB-based hydrogel and xerogel sorbents were analysed and compared based on characterisation analysis by using scanning electron microscopy (SEM), BrunauerEmmettTeller (BET), Fourier-Transform Infrared Spectroscopy (FTIR), and thermogravimetric analysis (TGA).The xerogel-based EFB is a better adsorbent than the hydrogel-based EFB because it has a larger pore volume (0.001449 cm3/g), larger pore size (63.7987 nm), higher moisture content (7.97%), lower ash content (12.55%), and is more thermally stable.The research is to compare two new adsorbents, namely Hydrogel and Xerogel, from EFB in terms of their characteristics.Both adsorbents show a highly toxic material uptake, especially EFB xerogel. This adsorbent is comparable with the other commercialised adsorbent. Thus, this product can be a highly potential adsorbent for gas and wastewater adsorption.The authenticity results of this article were found to be 15% similar. The novelty of this paper is to compare the two adsorbents, namely hydrogel and xerogel, that originated from EFB.

N, N′-methylene bisacrylamide/divinyl benzene based-highly cross-linked hybrid monolithic column: Production and its applications for powerful capture of four chlorophenols

In this paper, the role of the halogen bond in capillary monolithic column microextraction was explored for the first time. Benzene-1,3,5-tricarbohydrazide (BTH) was synthesized as a functional monomer, N, N′-methylene bisacrylamide (MBA) and divinyl benzene (DVB) were used as cross-linking agents, the hybrid monolithic column of poly (BTH-co-DVB-co-MBA) was prepared using methanol and polyethylene glycol as pore-forming agents and azodiisobutyronitrile as the initiator. Due to the existence of BTH, a large number of nitrogen atoms (Lewis base) were introduced into the monolithic column, which could form a halogen bond with chlorine-containing organic pollutants and enhance its adsorption performance. Based on the monolithic column, a sensitive and environment-friendly solid-phase microextraction technology was studied. The monolithic column was integrated with high-performance liquid chromatography (HPLC) to extract and detect four kinds of chlorophenol in real water samples. Under best conditions, the method showed excellent extraction ability and linearity, with a linear correlation coefficient of 0.9958–0.9987, a low detection limit (LOD) of 0.04–0.23 μg L−1 (S/N = 3), and relative standard deviation (RSD) less than 3.09%. The recovery rate was kept between 87.30% and 123.00%, and the RSD was less than 3.83%, which indicated that the column had powerful capture performance, high precision, and strong anti-matrix interference ability in the real sample, and had potential application value in practical work.

High-strength and self-degradable sodium alginate/polyacrylamide preformed particle gels for conformance control to enhance oil recovery

Excess water production has become an important issue in the oil and gas extraction process. Preformed particle gels (PPGs), show the capability to control the conformance and reduce excess water cut. However, conventional PPGs have poor mechanical properties and their swollen particles are easily damaged by shearing force when passing through the fractures in formations, meanwhile PPGs can be also degraded into various byproducts, leading to permanent damage to the reservoir permeability after temporary plugging. Herein, a novel type of dual cross-linked PPGs (d_PPGs) was designed and synthesized using sodium alginate (SA) and acrylamide (AAm), cross-linked with N, N′-methylenebisacrylamide (MBA) and Fe 3+ . Results show that d_PPGs have excellent mechanical properties with a storage modulus up to 86,445 Pa, which is almost 20 times higher than other reported PPGs. Meanwhile, d_PPGs can be completely degraded into liquid without any solid residues or byproducts and the viscosity of d_PPGs degraded liquid was found to be lower than 5 mPa·s. A laboratory coreflooding test showed that the plugging efficiency of d_PPGs was up to 99.83% on open fractures. The obtained results demonstrated that d_PPGs could be used as economical and environment-friendly temporary plugging agent with high-strength, self-degradation, thermal stability, and salt stability, thus making it applicable to a wide range of conformance control to enhance oil recovery.

Chitosan-Graft-Poly(acrylic acid) Superabsorbent’s Water Holding in Sandy Soils and Its Application in Agriculture

Sandy soil has a low ability to absorb and store low water, low nutrient content, and a high water evaporation rate, so it is not suitable to be used as agricultural land. Superabsorbents can be used to overcome these weaknesses. The purpose of this study was to measure the abilities of the superabsorbents, including water holding, swelling, and water retention of sandy soil enriched with superabsorbent, and to analyze the chitosan-graft-poly(acrylic acid) superabsorbent characteristics. The superabsorbent was prepared by mixing a chitosan solution with ammonium persulfate as an initiator and acrylic acid, which had been neutralized with KOH. Then, the mixture was cross-linked with N,N'-methylenebisacrylamide (MBA). The resulting superabsorbent gel was dried in an oven and then crushed for analysis. The results showed that an increase in chitosan concentration increased the gel fraction, swelling, reusability, and water holding. Meanwhile, an increase in chitosan concentration decreased water retention in sandy soils. The swelling kinetics can be predicted using the pseudo-second-order model with high accuracy (R2 value of 0.99).

Preparation of miniaturized hydrophilic affinity monoliths: Towards a reduction of non-specific interactions and an increased target protein density

In affinity chromatography, non-specific interactions between the ligands and the affinity column may affect the results, leading to misinterpretations during the investigation of protein-ligand interactions (detection of false positives in ligand screening, lack of specificity in purification). Such non-specific interactions may arise both from the underlying support or from the target protein itself. If the second ones are protein-dependent (and cannot be studied in a general framework), the first ones occur in the same way regardless of the immobilized target. We propose a methodology to identify the origin of such non-specific interactions with the underlying material of the affinity column. This methodology relies on the systematic investigation of the retention behavior of a set of 41 low-molecular weight compounds covering a wide chemical space (net charge, log D, functionality). We first demonstrate that the main source of non-specific interactions on the most commonly used GMA-co-EDMA monolith comes from hydrophobic effects. To reduce such non-specific interactions, we developed a new hydrophilic glycidyl methacrylate-based monolith by replacing the EDMA crosslinker by the more hydrophilic NN’ Methylenebisacrylamide (MBA). Optimization of the synthesis parameters (monomer content, initiation type, temperature) has focused on the reduction of non-specific interaction with the monolithic support while maximizing the amount of protein that can be grafted onto the monolith at the issue of its synthesis. The retention data of the 41 test solutes on the new poly(GMA-co-MBA) monolith shows a drastic reduction of non-specific interactions except for cationic compounds. The particular behavior of cationic compounds is due to their electrostatic interactions with carboxylic groups resulting from the partial acidic hydrolysis of amide groups of MBA during the epoxide ring opening step. So, the ring opening step in acidic media was replaced by a hot water treatment to avoid side reaction on MBA. The new monolith poly(GMA-co-MBA) not only has improved hydrophilic surface properties but also a higher protein density (16 ± 0.8 pmol cm−1 instead of 8 ± 0.3 pmol cm−1). To highlight the benefits of this new hydrophilic monolith for affinity chromatographic studies, frontal affinity chromatography experiments were conducted on these monoliths grafted with con A.

In Vitro and In Vivo Evaluation of Hydroxypropyl-β-cyclodextrin-grafted-poly(acrylic acid)/poly(vinyl pyrrolidone) Semi-Interpenetrating Matrices of Dexamethasone Sodium Phosphate.

In this paper, we fabricated semi-interpenetrating polymeric network (semi-IPN) of hydroxypropyl-β-cyclodextrin-grafted-poly(acrylic acid)/poly(vinyl pyrrolidone) (HP-β-CD-g-poly(AA)/PVP) by the free radical polymerization technique, intended for colon specific release of dexamethasone sodium phosphate (DSP). Different proportions of polyvinyl pyrrolidone (PVP), acrylic acid (AA), and hydroxypropyl-beta-cyclodextrin (HP-β-CD) were reacted along with ammonium persulphate (APS) as initiator and methylene-bis-acrylamide (MBA) as crosslinker to develop a hydrogel system with optimum swelling at distal intestinal pH. Initially, all formulations were screened for swelling behavior and AP-8 was chosen as optimum formulation. This formulation was capable of releasing a small amount of drug at acidic pH (1.2), while a maximum amount of drug was released at colonic pH (7.4) by the non-Fickian diffusion mechanism. Fourier transformed infrared spectroscopy (FTIR) revealed successful grafting of components and development of semi-IPN structure without any interaction with DSP. Thermogravimetric analysis (TGA) confirmed the thermal stability of developed semi-IPN. X-ray diffraction (XRD) revealed reduction in crystallinity of DSP upon loading in the hydrogel. The scanning electron microscopic (SEM) images revealed a rough and porous hydrogel surface. The toxicological evaluation of semi-IPN hydrogels confirmed their bio-safety and hemocompatibility. Therefore, the prepared hydrogels were pH sensitive, biocompatible, showed good swelling, mechanical properties, and were efficient in releasing the drug in the colonic environment. Therefore, AP-8 can be deemed as a potential carrier for targeted delivery of DSP to treat inflammatory bowel diseases.

Adsorption and removal of Cr(VI) from aqueous solution with amine-functionalized porous boron nitride

Heavy metals in water environment do great harm to the life and health of the public and the stability of the ecological environment. Therefore, it is necessary to find an efficient solution to deal with the increasingly serious problem of heavy metal pollution. In this paper, N, N'-methylene bisacrylamide was loaded on porous boron nitride (pBN) surface with a simple synthesis method using 3-aminopropyltriethoxysilane as a coupling agent for the adsorption of Cr(VI). The prepared adsorbents were characterized with XRD, SEM, TEM, FTIR, XPS, BET, and other analytical methods. We discovered that the capacity of pBN-AS@MBA reached 83.78 ​mg/g, which was significantly higher than that of pBN, with an initial concentration of 20 ​mg/L of Cr(VI). Besides, the chemosorption of exothermic spontaneity predominated the entire process, determined from pseudo-second-order kinetics, intra-particle diffusion model, thermodynamics, and Langmuir isotherm. Not only Cr(VI) chemically react with amine groups on the sorbent, but also elicited electrostatic attractions. The reusability of sorbent was proved with a reduction rate of lower than 20%, after a few cycles of running.

Building Polymeric Framework Layer for Stable Solid Electrolyte Interphase on Natural Graphite Anode.

The overall electrochemical performance of natural graphite is intimately associated with the solid electrolyte interphase (SEI) layer developed on its surface. To suppress the interfacial electrolyte decomposition reactions and the high irreversible capacity loss relating to the SEI formation on a natural graphite (NG) surface, we propose a new design of the artificial SEI by the functional molecular cross-linking framework layer, which was synthesized by grafting acrylic acid (AA) and N,N'-methylenebisacrylamide (MBAA) via an in situ polymerization reaction. The functional polymeric framework constructs a robust covalent bonding onto the NG surface with -COOH and facilitates Li+ conduction owing to the effect of the -CONH group, contributing to forming an SEI layer of excellent stability, flexibility, and compactness. From all the benefits, the initial coulombic efficiency, rate performance, and cycling performance of the graphite anode are remarkably improved. In addition, the full cell using the LiNi0.5Co0.2Mn0.3O2 cathode against the modified NG anode exhibits much-prolonged cycle life with a capacity retention of 82.75% after 500 cycles, significantly higher than the cell using the pristine NG anode. The mechanisms relating to the artificial SEI growth on the graphite surface were analyzed. This strategy provides an efficient and feasible approach to the surface optimization for the NG anode in LIBs.

Hydrolyzed Arabic gum-grafted-polyacrylonitrile@ zinc ferrite nanocomposite as an efficient biocatalyst for the synthesis of pyranopyrazoles derivatives

A catalytic methodology for the effective synthesis of pyrazolopyrazole derivatives using a combination of hydrolyzed Arabic gum-g-polyacrylonitrile/ZnFe2O4 (Hyd AG-g-PAN/ZnFe2O4) catalyst, malononitrile, and aromatic aldehyde, hydrazine hydrate, and ethyl acetoacetate is described. This protocol relies on the use of environment-friendly heterogeneous catalyst based on zinc ferrite magnetic particles in combination with Arabic gum (AG) as the backbone, N, N methylene bisacrylamide (MBA) as a crosslinking agent, ammonium persulfate (APS) as an initiator, and alkaline solution for hydrolyzation. This bio-based catalyst with a soft three-dimensional cross-linked framework contains distinct acidic and basic sites and could be applied as a powerful catalyst for the one-pot synthesis of pyranopyrazoles derivatives. Using an external magnet, the superparamagnetic nanocomposite could be easily separated. Furthermore, the catalyst can well be utilized at least six times in subsequent reaction cycles before losing its activity. FT-IR, EDX, TGA, FESEM, VSM, and XRD methods were used to characterize the produced catalyst. Taking 0.01 g of catalyst at 80 °C in a green solvent of water/ethanol, the greatest output of dihydropyrano [2,3-c] pyrazole was 96% in 15 min. A simple technique, short reaction time, high yield, and the catalyst's reusability and stability are just a few of the study's advantages.

High‐strength, ultrastretchable hydrophobic association hydrogel reinforced by tailored modified carboxymethyl cellulose

AbstractA new pathway to construct high‐strength, ultrastretchable hydrogels based on tailored modified carboxymethyl cellulose (TMCMC)and hydrophobic association(HPA) system was investigated. TMCMC was prepared from degradation of carboxymethyl cellulose (CMC)/N,N′‐methylene bisacrylamide (MBA) chemical cross‐linked hydrogels. The residual double bonds of TMCMC, confirmed by 1H‐NMR and FTIR analysis, reacted with acrylamide in HPA to form TMCMC/HPA hydrogels, and the homogeneous and fine spatial network structure of TMCMC/HPA hydrogel could be observed by scanning electron microscopy. Rheological analysis revealed that the coexistence of physical and chemical crosslinking in TMCMC/HPA hydrogels. Further studies showed that TMCMC/HPA hydrogel with MBA content of 0.5 wt% has outstanding mechanical properties, and its fracture stress, elongation and tensile strength reach 1.17 MPa, 3717.05% and 15.68 MJ·m−3, respectively. Moreover, the hydrogel displayed good swelling resistance and stable strain electrical signal response.

Preparation of Isopropyl Acrylamide Grafted Chitosan and Carbon Bionanocomposites for Adsorption of Lead Ion and Methylene Blue.

Wastewater, which is rich with heavy elements, dyes, and pesticides, represents one of the most important environmental pollutants. Thus, it has been significant to fabricate environmentally friendly polymers with high adsorption ability for those pollutants. Herein, crosslinked chitosan (C-Cs) was prepared using isopropyl acrylamide and methylene bisacrylamide. Carbon nanoparticles (C-NPs) were also obtained by the treatment of the agricultural wastes, which was used with C-Cs to prepare C-Cs/C-NPs nanocomposite (C-Cs/C-NC). Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscope (TEM) were used to investigate the prepared adsorbent. C-Cs, C-NPs, and C-Cs/C-NC were used in water treatment for the adsorption of lead ions (Pb+2) and methylene blue (MB). The adsorption process occurred by the prepared samples was investigated under different conditions, including contact time, as well as different doses and concentrations of adsorbents. The findings exhibited that the adsorption of Pb+2 and MB by C-Cs/C-NC was higher than C-Cs and C-NPs. In addition, the kinetic and isotherm models were studied, where the results showed that the adsorption of Pb+2 and MB by various adsorbents obeys pseudo-second-order and Langmuir isotherms, respectively.