Presence Of Potassium Persulfate Research Articles

Graft copolymers of collagen and acrylic monomers—Reagents for sizing of cotton yarn

AbstractA new highly effective sizing reagent based on grafted collagen copolymers has been proposed for cotton yarn. The copolymers were synthesized by reacting an aqueous solution of collagen with acrylic monomers—acrylic, matacrylic acids, and their amides in the presence of potassium persulfate. Based on Scanning electron microscopy ‐ Energy dispersive (SEM‐EDS) analysis data, the composition of the copolymers was determined. Unsaturated acids are more actively grafted onto collagen than their amides. When a polymer film is formed from a solution of a collagen copolymer with (meth)acrylic acid, microcracks appear on the surface of the sample; microcracks are absent in films of copolymers with (meth)acrylamide. Films of copolymers, especially methacrylamide, are quite flexible and contribute to a significant improvement in the properties of the yarn. The tensile strength of yarn sized with copolymers increases by 20%–65% compared to unsized yarn, and by 13%–38% compared to yarn sized with a starch solution. At the same time, the relative tensile elongation of the experimental yarn improves by 14%–58%, while this property of starch‐size yarn deteriorates by 14%–22% compared to unsized yarn. The complete removal of graft copolymers from the surface of the yarn in the process of biochemical desizing using the enzyme protease is shown.Highlights Graft copolymerization of (meth)acrylamide with collagen was carried out. Grafting is initiated by the interaction of collagen with potassium persulfate. The synthesized copolymers are effective sizing reagents for cotton yarn. The copolymer with poly(meth)acrylamide forms a flexible and stable film. The protease enzyme completely removes the size from the surface of the yarn.

Unmasking the Electrochemiluminescence Properties of Ternary Mn/Fe/Co Metals Doped Porous g-C3N4 Fiber-like Nanostructure.

Graphitic-phase carbon nitride (g-C3N4) materials have exhibited increasingly remarkable performance as emerging electrochemiluminescence (ECL) emitters, owing to their unique optical and electronic properties; however, the ECL merits of porous g-C3N4 nanofibers doped with ternary metals are not yet explored. Deciphering the ECL properties of trimetal-doped g-C3N4 nanofibers could provide an exquisite pathway for ultrasensitive sensing and imaging with impressive advantages of minimal background signal, great sensitivity, and durability. Herein, we rationally synthesized g-C3N4 nanofibers doped atomically with Mn, Fe, and Co elements (Mn/Fe/Co/g-C3N4) in a one-pot via the protonation in ethanol and annealing process driven by the rolling up mechanism. The ECL performance of g-C3N4 with and without metal dopants was investigated and compared with standard Ru(bpy)32+ in the presence of potassium persulfate (K2S2O8) as the coreactant. Notably, g-C3N4 nanofibers doped with metal ions exhibited an ECL efficiency of 483% that was 4.83 times higher than that of Ru(bpy)32+. Mechanistic investigations unveiled that the g-C3N4 nanofibers possess a large surface area and, as a result, exhibit a reduced interfacial impedance within the porous microstructure. These factors contribute to the acceleration of charge transfer rates and the stabilization of charge carriers and excitons, ultimately facilitating the ECL process. This research endeavor may pave the way for a new hot research area and serves as a powerful tool for elucidating fundamental inquiries of ECL on one-dimensional g-C3N4 nanostructures.

New luminescent hydrophilic iridium(III) nanoflower at low potential for electrochemiluminescence immunosensing

Screening effective luminophore is always one of the most essential concerns in highly sensitive electrochemiluminescence (ECL) bioanalysis. Here, a new nanoflower-like iridium(III) J-aggregate (T-Ir) was prepared via nonionic surfactant assisted reprecipitation technique, which possessed good reductive-oxidative ECL activity and performed a strong ECL emission around 626 nm at low potential (−1.10 V) in the presence of potassium persulfate. Thus, T-Ir was employed as a luminophore and good biocompatible matrix to load large amounts of capture antibodies (Ab1). Meanwhile, gold nanoparticles capped cuprous oxide nanocubes (Cu2O@Au) were used as the efficient quencher to label detection antibodies (Ab2). While different dosages of carcinoembryonic antigen (CEA) were introduced via sandwich immunoreaction, the ECL intensity was significantly dropped due to electrochemiluminescence resonance energy transfer from energy donor (T-Ir) to the acceptor (Cu2O@Au), achieving the highly sensitive detection of CEA. The proposed immunosensor showed a linear concentration range from 1 fg·mL−1 to 80 ng·mL−1 with a low limit of detection of 0.93 fg·mL−1 (S/N = 3). It featured superior stability, selectivity, reproducibility and practicability. With the successful demonstration of hydrophilic iridium(III)-based nanomaterials, sensing strategies for various biomarkers detection in diseases diagnosis will flourish.

INVESTIGATION OF MODIFIED POLYACRYLAMIDE FOR OIL DISPLACEMENT

At present, the use of surfactants and water-soluble polyelectrolytes, which act as stabilizing and selective agents, is inextricably linked with the successful solution of the technological issues in the world of chemical, oil and other industries. The purpose of the work is to synthesize and study the physicochemical properties of modified polyacrylamide with gossypol resin and further crosslinking in the presence of potassium persulfate and sodium sulphate to displace oil. Methods. To establish the spectral characteristics of the modified PAA, IR spectra have been taken on an IR-Fourier spectrometer. For the structural-elemental composition (SEM), a Jeol JSM-6490l V electron microscope has been used. The viscosity of modified PAA solutions has been measured in a Ubellode capillary viscometer with a hanging level. Results and discussion. The studies, carried out by the authors of the study of the colloid-chemical properties of polymer composites, allow us to conclude that the reagents obtained during the hydrolysis of vat residues of fatty acids distillation with sodium hydroxide with further cross-linking in the presence of potassium persulfate and sodium sulphate have good surfaceactive and emulsifying properties, which is important when displacing oil from layers. The surface tension of polymer compositions has been studied. With an increase in the concentration of the solution, the surface tension decreases, i.e., the surface activity increases. Conclusion. The research results show that the injection of a polymer reagent solution can increase the oil displacement efficiency by 6-7%.

POLYMER COMPOSITION FOR OIL DISPLACEMENT

The development of composite polymers for oil displacement and improving the performance of oil wells is an urgent task. In this article, the authors made an analysis of the state of the problem of enhanced oil recovery of oil reservoirs based on water-soluble polymers. The issues of synthesis and study of the physicochemical properties of modified polyacrylamide with fatty acids, gossypol resin and further crosslinking in the presence of potassium persulfate and sodium sulphate to enhance oil recovery are considered.

Preparation of thermally stable organic-inorganic hybrid nanocomposites from chemically functionalized oxidized graphite by in situ catalytic oxidative decarboxylation

ABSTRACT In this study, the preparation of thermally stable organic-inorganic hybrid nanocomposites from chemically functionalized oxidized graphite is carried out by in-situ catalytic oxidative decarboxylation of 3,5-dinitrobenzoic acid (reactant) in the presence of potassium persulfate (oxidant), silver nitrate (catalyst) and graphite (support) under thermal or microwave conditions. The effects of heat transfer and dosages of reactant, catalyst and oxidant on the crystalline structure and the morphology of nanocomposites are studied in detail. The prepared nanocomposites are characterized by EDS, elemental mapping, FE-SEM, FT-IR and XRD. The thermal stability of nanocomposites is examined by TGA and DSC. EDS shows that nanocomposites are composed of C, O, N, S, K and Ag elements. FT-IR exhibits that the graphitic layers in nanocomposites are mainly oxidized and functionalized with carboxyl, carbonyl, hydroxyl, epoxy, sulfate, nitrate and nitroaryl groups. Addition of nitroaryl groups to nanocomposites is also supported by an increase found in their C and N contents. XRD demonstrates the coexistence of both oxidized amorphous carbon and graphite in combination with different levels of organic and inorganic phases. The prepared nanocomposites show good thermal stability. The total area of the DSC curve in these nanocomposites compared to graphite is enhanced.

Access to Diverse Seleno-spirocyclohexadienones via Ag(II)-Catalyzed Selenylative ipso-Annulation with Se and Boronic Acids.

An efficient and straightforward synthesis of diversified seleno-azaspiro-2,5-cyclohexadienones from N-(4-methoxy aryl)propiolamides using elemental selenium and boronic acids has been demonstrated. The reaction proceeds through silver-catalyzed oxidative dearomatization in the presence of potassium persulfate (K2S2O8) as the oxidant. Further, this approach was extended to N-(4-methoxy aryl)propiolates and biaryl ynones to access the corresponding selenylated oxospiro-2,5-cyclohexadienones and spiro[5,5]trienones, respectively. The present three-component method offers the diverse substitutions on selenium involving two C–Se and one C–C bond formations.

Facile synthesis of hierarchical porous two-dimensional N-doped carbon nanosheets as bi-functional electrode for superior supercapacitor and photo-catalyst

The hierarchical porous nitrogen-doped two-dimensional carbon (HNGC) was prepared by simple calcination of magnesium sulfate (MgSO4) and self-synthesized nitrogen-doped two-dimensional graphene-like carbon at a mild temperature in oxygen. The influence MgSO4 on the morphology, structure and chemical composition of the prepared HNGC samples were studied using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, surface area analysis, X-ray photoelectron microscopy and elemental analyzer. HNGC-2 exhibited a uniform three-dimensional coral-like porous inter-connected structure, large specific surface area, high pore volume, and no loss of nitrogen content. HNGC-2 demonstrated an excellent rate capability of 62.8% at 20 A g−1, outstanding stability of 96.1% following 5000 cycles and the assembled symmetric supercapcitor achieved 12.5 Wh kg−1 at a 350 Wkg-1 and 7.5 Wh kg−1 at 3500 Wkg-1. The novel method was also found to be effective for facilitating the electrochemical performance of commercial biomass active carbon. In addition, HNGC-2 was used for the photo-catalytic degradation of methylene blue and over 99% of methylene blue was successfully degraded under 25-min visible irradiation in the presence of potassium persulfate. The enhanced electrochemical performance and the excellent photo-catalytic performance of HNGC-2 indicated that porous carbon can be successfully activated using an appropriate oxidation strategy.

Molecular characteristics, mechanism of synthesis, adhesive properties of graft copolymer of chloroprene rubber with acrylic acid

AbstractSynthesized graft copolymers of chloroprene rubber with acrylic acid in a solution of a mixture of dimethylformamide and benzene, in the presence of potassium persulfate. The gravimetric method determined the orders of the reaction rate by the concentrations of acrylic acid (2.0) and potassium persulfate (1.2), the total activation energy of the process (24.4 kJ/mol). It was found that the degree of grafting increases up to 140% with an increase in the concentration of the monomer, initiator, temperature, and process time. The efficiency of grafting changes insignificantly with changes in synthesis conditions and has a high value (67%–91%) over a wide range of concentrations, temperatures, and times. With an increase in the concentration of acrylic acid and a process time of up to 8 h, the molecular weight of the grafted polyacrylic acid chains increases to 38,000. IR Fourier,1H, and13C NMR spectroscopic studies established the mechanism of graft copolymerization. Radical active centers are formed as a result of hydrogen abstraction from the rubber molecule after interaction with potassium persulfate. Copolymers synthesized at a mass ratio of rubber:acrylic acid from 1:0.5 to 1:2, have excellent adhesion to the surface of the skin and textile material.

Near-Infrared Electrogenerated Chemiluminescence from Simple Copper Nanoclusters for Sensitive Alpha-Fetoprotein Sensing.

Exploiting low cost, water-soluble, and near-infrared (NIR) emissive electrochemiluminophores (ECLphores) is significantly important for biological applications. In this study, bright and NIR electrogenerated chemiluminescence (ECL) emissive copper nanoclusters (Cu NCs) were synthesized through a facile one-pot wet chemical reduction method. ECL properties of obtained Cu NCs were examined in the presence of potassium persulfate, resulting in maximum intensity at 735 nm, at least 135 nm red-shifted with respect to all other Cu NCs. Electrochemistry, photoluminescence (PL), and spooling ECL spectroscopies were used to track NIR ECL emission of Cu NCs ascribed to the monomeric excited states. Due to the abundant binding sites of bovine serum albumin (BSA) to anchor target biomolecules, a sandwich-type ECL immunosensor was thus fabricated using such BSA-templated Cu NCs as tags and alpha fetoprotein antigen (AFP) as a model protein for the first time. Without assisting any signal amplification strategies, the proposed NIR ECL biosensor exhibited a wide linear range (1-400 ng mL-1) and low detection limit (0.02 ng mL-1) as well as superior selectivity and reproducibility and was successfully applied in real human serum sample determination. This work sets the stage for the development of novel non-noble metal nanoclusters for large-scale and emerging nanotechnology applications.

ZnO-Co3O4/N-C Cage Derived from the Hollow Zn/Co ZIF for Enhanced Degradation of Bisphenol A with Persulfate.

The zeolitic imidazolate framework (ZIF)-67 microcrystal was employed as a precursor to synthesize the hollow ZIF-8/ZIF-67 composite via the epitaxial growth of ZIF-8 on ZIF-67, in situ self-sacrifice, and excavation of ZIF-67. The hollow ZIF-8/ZIF-67 composite was successfully transformed to the ZnO-Co3O4/N-C cage by thermal treatment, which was further used as the catalyst for the oxidative degradation of bisphenol A (BPA) in the presence of potassium persulfate (PS). In comparison with the Co3O4/N-C and Co3O4 obtained from pure ZIF-67 and cobalt nitrate, the ZnO-Co3O4/N-C cage demonstrated a more than four fold-higher activity and robust reusability. Based on structural analysis, the enhanced catalytic performance could be ascribed to the small, highly dispersed cobalt oxide particles, the hollow structure that facilitated the transportation of the molecules, and the synergistic effect between cobalt oxide and nitrogen-doped carbon in the composite. Besides, the effect of dosage of PS, BPA, and the co-existing components such as chloride ion, methanol, and t-butyl alcohol was carefully investigated to propose the possible mechanism. This study would give new insights into the design of functional composite materials from metal organic frameworks and the development of their application in environmental pollution disposal.

Preparation of Nanochitin/Polystyrene Composite Particles by Pickering Emulsion Polymerization Using Scaled-Down Chitin Nanofibers

In this study, we investigate the Pickering emulsion polymerization of styrene using scaled-down chitin nanofibers (SD-ChNFs) as stabilizers to produce nanochitin/polystyrene composite particles. Prior to emulsion polymerization, an SD-ChNF aqueous dispersion was prepared by disintegrating bundles of the parent ChNFs with an upper hierarchical scale in aqueous acetic acid through ultrasonication. After styrene was added to the resulting dispersions, the mixtures at the desired weight ratios (SD-ChNFs to styrene = 0.1:1–1.4:1) were ultrasonicated to produce Pickering emulsions. Radical polymerization was then conducted in the presence of potassium persulfate as an initiator in the resulting emulsions to fabricate the composite particles. The results show that their average diameters decreased to a minimum of 84 nm as the weight ratios of SD-ChNFs to styrene increased. The IR and 1H-NMR spectra of the composite particle supported the presence of both chitin and polystyrene in the material.

Electrochemical Synthesis of Polymer Complexes with Selected Metals Based on 1-Vinyl-1,2,4-triazole

A single-stage electrochemical synthesis of polymer complexes of Fe, Co, Ni, and Cu based on 1-vinyl-1,2,4-triazole has been elaborated. It has been found that 1-vinyl-1,2,4-triazole can be electropolymerized via the double bonds opening in the presence of potassium persulfate. At low current density, colored metal-polymer coatings have been formed at the surface of electrodes, and powders have been obtained at high current density. The composition and structure of the polymeric complexes have been elucidated by means of infrared spectroscopy, gas-liquid chromatography, elemental analysis, and thermogravimetric analysis.

Preparation and characterization of AM-co-APTAC/TiO2 nanocomposite for environmental applications

TiO2 nanoparticles are used as self-cleaning and anti-bacterial agents due to their excellent photo-catalytic activities. An organic–inorganic hybrid is prepared via radical graft polymerization. First, the TiO2 nanoparticle surface was modified by vinyltriacetoxysilane as coupling agent using a sol–gel technique in aqueous media. Afterwards, the modified nanoparticles were copolymerized by 3-acrylamidopropyltrimethyl ammonium chloride and acrylamide monomer in presence of potassium persulfate as initiator. The synthesized nanocomposite was then used for the optimal removal of suspended solids and dyestuff from an industrial wastewater. FTIR spectra proved the connection of polymeric chains onto the surface of the nanoparticles. SEM micrographs along with Ti-map, TGA technique, x-ray diffraction patterns and EDX analysis were used for characterization and properties of nanocomposite. It was clearly shown that in the presence of nanocomposite, the degradation of Rh.B occurred well.

Starch-g-PCHMA copolymers: preparation and properties

The chemical modification of potato starch by cyclohexyl methacrylate monomer in the presence of potassium persulfate as an initiator and some of physico–chemical properties of the resulted copolymers have been presented. On a basis of the received results, the maximum of the grafting (45.3% ± 0.2) was found using the following conditions: potato starch to cyclohexyl methacrylate ratio 1:3, an initiator concentration 1.5 mass%, the reaction temperature 70 °C and the reaction time 90 min. The obtained copolymers showed ca. 1.9–5.5 times lower polar solvent swelling, ca. 2.2–9.6 times higher non-polar swelling, ca. 1.6–3.6 times higher moisture resistance and ca. 1.9–6.3 times higher chemical resistance as compared to these properties of unmodified potato starch. Moreover, as it was stated based on the TG/DTG analyses, the novel materials were thermally stable up to the temperature of ca. 180 °C. Their pyrolysis process has included at least four stages where the emission of different structure volatiles was detected by a FTIR analysis.

Swelling Behaviors of Super-Absorbent Hydrogel based Waste: Bacteria Bran

Firstly, a newly developed bacteria brans (BB) /poly (acrylic/acrylamide/2-acrlylamido-2-methyl-1-propanesulfonic acid) (AA/AM/AMPS) hydrogel was reported, which cross-linked by N, N’-methyl-enebisacrylamide in the presence of potassium persulfate as a free radical initiator. The BB, a waste after the cultivation of the edible fungus, is composite of lignin, cellulose and other carbohydrates, which are beneficial to enhance the water absorbency properties of the super-absorbent hydrogel. Secondly, the chemical structure and morphologies of the hydrogel were characterized by ourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and the thermogravimetric analysis (TGA). The results confirmed that superabsorbent comprised a coarse surface and the porous network structure with carboxylate, carboxamide and sulfate. Finally, the swelling behaviors of the BB/P (AA/AM/AMPS) hydrogel have been studied, achieving favourable water absorbency properties (589 g/g). The effect of swelling behaviors of the hydrogel on the pH value and the concentration of the salt solution were also studied. This work improves the swelling behaviors of the hydrogel. Importantly, it provides the way to devise the hydrogel with environmental compatibility and low-cost, which is useful in many potential applications, such as agriculture.

Probing the electrical and dielectric properties of polyaniline multi-walled carbon nanotubes nanocomposites doped in different protonic acids

Polymer nanocomposites with vital reinforcements of conductive fillers have evinced as next-generation high-performance materials with multi-functional applications. Herein, we report the facile synthesis of thermally stable, highly electrically conducting polyaniline multi-walled carbon nanotubes (PANI/MWCNT) nanocomposites doped in two different protonic acids, i.e. hydrochloric acid (HCl) and sulphuric acid (H2SO4). The doping acids significantly affect the electric and dielectric properties of conducting polymer nanocomposites. The paper probes in the synergistic effects of MWCNTs and the effect of doping acid on the thermal stability, conductivity and dielectric properties of the nanocomposites based on PANI nanofibres. The structural, morphological, optical, thermal and electrical properties were evaluated through X-ray diffraction, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, thermogravimetric analysis and two-point probe technique. Ascribed to the high interfacial interaction between PANI and MWCNT, and considering the effect of doping acids, nanocomposites with high thermal stability, enhanced conductivity and high dielectric constant that can store large electrical charges have been synthesized by surfactant-assisted, in situ oxidative polymerization of aniline, in the presence of potassium persulfate as oxidant. The micellar structure of surfactant assists the dispersion of MWCNTs as well as the formation of PANI/MWCNT tubular structures. The effect of surfactant below and above critical micelle concentration was also studied. This complete study would affirm such a nanocomposite which procures excellent electrical and dielectric properties for microelectronic applications.

Nest-like Co3O4 and PdOx/Co3O4 synthesized via metal organic framework with cyclodextrin for catalytic removal of Bisphenol A by persulfate

In the present work, Co3O4 and PdOx/Co3O4 nanocrystals were obtained via the calcination of Hydroxypropyl-β-cyclodextrin (HP-β-CD) assistant-synthesized ZIF-67 and Pd(acac)2/ZIF-67, respectively. The results suggested that although the HP-β-CD was used during the preparation of ZIF-67 in the ethanol, it could be removed by washing the ZIF-67 for several times. The structure and composition of the Co3O4 and PdOx/Co3O4 prepared without and with the assistance of HP-β-CD were investigated. Finally, the results from the catalytic oxidation of Bisphenol A in the presence of potassium persulfate indicated that a better performance was observed over the HP-β-CD assistant synthesized Co3O4, possibly due to an increased specific surface area. In addition, it was found that a high oxidation state (IV) of Pd species in the PdOx/Co3O4 synthesized with the help of HP-β-CD was noticed compared with that synthesized without HP-β-CD. It was worth noting that the further catalytic tests suggested HP-β-CD assisted synthesized PdOx/Co3O4 displayed more than 2-fold higher activity compared with Co3O4 as well as PdOx/Co3O4, which was possibly ascribed to the better dispersion as well as the presence of Pd(IV) species, respectively.

Access to highly substituted oxazoles by the reaction of α-azidochalcone with potassium thiocyanate.

The reactivity of α-azidochalcones has been explored for the preparation of highly substituted oxazoles via a 2H-azirine intermediate. The azidochalcones, when treated with potassium thiocyanate in the presence of potassium persulfate, lead to 2,4,5-trisubstituted oxazoles in good yields. Incidentally, 2-aminothiazoles are the products when ferric nitrate is employed instead of persulfate in the above reaction.

Lignin-methyl methacrylate polymer as a hydrophobic multifunctional material

In this work, the modification of lignin (KL) with methyl methacrylate (MMA) is presented via free-radical polymerization in the presence of potassium persulfate as an initiator. One-step purification of the reaction products was also attested for generating KL-MMA with 95 wt% yield and 85 wt% MMA conversion. The characteristics of KL-MMA were studied comprehensively employing 1H NMR, 31P-NMR, 13C-NMR, SEM, FTIR, and GPC. KL-MMA demonstrated significantly higher thermal stability and UV absorption compared with unmodified KL and PMMA homopolymer. The hydrophobicity of lignin derivatives was substantially improved via reacting with acrylate monomer (a contact angle change from 25° for KL to 88° for KL-MMA). The performance of KL-MMA as an adsorbent for humic acid (HA) was also evaluated in detail by means of a Quartz crystal microbalance with dissipation (QCM-D). The results confirmed the superior adsorption performance of KL-MMA to that of KL and PMMA for HA. The modified lignin polymer possessed a multitude of excellent features including remarkable hydrophobic properties and adsorption capacity. The product offers a wide range of applications possibly in food packaging and water purification systems.