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Epoxy resins, as important thermosetting polymers, exhibit excellent adhesion to various substrates. In view of this, reticulate coating of triglycidyl isocyanate with triethylenetetramine was introduced onto the surface of poly(styrene‐divinylbenzene) utilizing amine curing reaction to obtain poly(styrene‐divinylbenzene)@triglycidyl isocyanate‐triethylenetetramine composite microspheres. The amino groups and epoxy groups of triglycidyl isocyanate‐triethylenetetramine endowed poly(styrene‐divinylbenzene) with good reactivity, which could be quaternized under mild conditions to obtain an anion exchange chromatographic stationary phase. The quaternized poly(styrene‐divinylbenzene)@triglycidyl isocyanate‐triethylenetetramine was characterized by scanning electron microscope, Fourier‐transform infrared spectroscopy, N2 adsorption‐desorption experiment, et al. The chromatographic performance of the customized column was evaluated by separating seven conventional anions, organic weak acids, and carbohydrates. Poly(styrene‐divinylbenzene)@triglycidyl isocyanate‐triethylenetetramine possesses the uniform size of poly(styrene‐divinylbenzene) microspheres and good reactivity of triglycidyl isocyanate‐triethylenetetramine, which offers a flexible strategy for the preparation of anion exchange stationary phase. The column exhibits excellent chemical and mechanical stability and chromatographic performance. Finally, the column was successfully applied for the determination of nitrite in pickles. [ABSTRACT FROM AUTHOR]

Chitin is one of the most abundant biopolymers after cellulose, which is present in the cell wall of fungi, the cuticle of insects, and in the exoskeleton of crustaceans such as crabs and shrimps. From the deacetylation of chitin, chitosan is obtained, whose characteristics strongly depend on the degree of deacetylation and its molecular weight. In fact, it can be said that chitosan is the most abundant amino polysaccharide in nature, which is also known as a non-toxic compound. Chitosan has received much attention due to its unique properties such as biocompatibility, biodegradability, antibacterial activity, etc. But due to its low solubility in physiological pH, it is not possible to benefit from many of its properties. Therefore, many attempts have been made to produce its derivatives that have the ability to dissolve in such a condition. One of the most important methods of increasing the solubility of chitosan is its chemical modification, which is done with the so-called quaternization technique. In this method, a modifying agent by establishing a covalent bond with carbon number two of chitosan (C2) increases its solubility in water and at physiological pH. In this article, while re-introducing the unique features of chitosan, various methods of preparing quaternized chitosan using some common chemical compounds such as GTMAC, EPTMAC, CH3I, DMS will be investigated and the characteristics and applications of the produced quaternized chitosan will be described. [ABSTRACT FROM AUTHOR]

The reaction of ethyl pyridine-2-ylcarbamate with phenacyl bromides in acetonitrile gave 2-aryl-1-(ethoxycarbonyl)-2-hydroxy-2-phenyl-2,3-dihydro-1H-imidazo[1,2-a]pyridine-4-ium bromides which were con--verted into 2-arylimidazo[1,2-a]pyridines by heating in acetic anhydride, followed by treatment with potassium carbonate. [ABSTRACT FROM AUTHOR]

In this work, two structurally different monoamines (trimethylamine [TMA] and N‐methylpiperidine [N‐MPip]) are used for the amination of a g‐VBC‐15 graft copolymer, obtained by the functionalization of a mechanically robust, commercially available styrene–butadiene block copolymer (SB) with vinylbenzyl chloride (VBC) via solution free‐radical polymerization. Results demonstrate that g‐VBC‐15‐based membranes quaternized with TMA have superior electrochemical performance than N‐MPip counterparts; while, the mechanical properties are good and only slightly inferior to those of N‐MPip. Therefore, TMA is the selected monoamine to be alternatively mixed with two polyamines (tetramethyl‐1,3‐propanediamine [TMPDA] and N,N,N',N",N"‐pentamethyldiethylenetriamine [PMDETA]) into different proportions, in order to modulate the average functionality of the amination mixture in terms of number of amine functional groups available for the quaternization reaction of the membranes. g‐VBC‐15‐based membranes derived therefrom are extensively characterized to assess their thermal, mechanical, and ex situ electrochemical properties. Results indicate that membranes quaternized with a TMA/PMDETA mixture (90:10 in mole) display the highest conductivity among all the investigated membranes aminated with polyamine‐based mixtures. Moreover, they have comparable mechanical and electrochemical properties to those quaternized with TMA, while exhibiting a reduced water uptake. [ABSTRACT FROM AUTHOR]

In this work, we present the modification of a medical-grade silicone catheter with the N-vinylimidazole monomer using the grafting-from method at room temperature and induced by gamma rays. The catheters were modified by varying the monomer concentration (20–100 vol%) and the irradiation dose (20–100 kGy). Unlike the pristine material, the grafted poly(N-vinylimidazole) chains provided the catheter with hydrophilicity and pH response. This change allowed for the functionalization of the catheters to endow it with antimicrobial features. Thus, the quaternization of amines with iodomethane and bromoethane was performed, as well as the immobilization of silver and ampicillin. The inhibitory capacity of these materials, functionalized with antimicrobial agents, was challenged against Escherichia coli and Staphylococcus aureus strains, showing variable results, where loaded ampicillin was amply better at eliminating bacteria. [ABSTRACT FROM AUTHOR]

Chitin, the most abundant renewable polysaccharide in the marine environment, presents restricted applications due to its low solubility. Chitin quaternization can produce a water-soluble chitin derivative with a wide pH range due to the existence of a permanent positive charge on the polymer backbone. Quaternized chitin (QC) has received increasing attention owing to its superior water solubility and antibacterial action. This review aims to outline synthesis techniques, functional materials, and multiple applications of QC. The synthesis techniques of QC, such as heterogeneous reactions and homogeneous reactions, are introduced first. Then we discuss some developed QC-based functional materials, especially micelles, hydrogels, coatings, and sponges. The progress in the applications of QC, such as wound dressings and drug/gene delivery, is also reviewed. We hope that this review can provide new inspiration for expanding the application scope of QC. [ABSTRACT FROM AUTHOR]

Quaternary carbons are embedded in various natural products, pharmaceuticals, and organic materials. However, constructing this valuable motif is far from trivial. Conventional approaches mainly rely on classical polar disconnections and encounter bottlenecks concerning harsh conditions, functional group tolerance, regioselectivity, and step economy. In this context, Kawamata, Baran, Shenvi, and co‐workers recently demonstrated that two feedstock chemicals, alkyl carboxylic acids and olefins, could be utilized to construct tetrasubstituted carbons in the presence of an inexpensive iron porphyrin catalyst and a suitable reductant combination through quaternization of the radical intermediates. The method enables access to various sterically encumbered quaternary carbons under mild and robust conditions. Taking a complete detour from conventional approaches, the present heteroselective radical–radical coupling simplifies the synthesis of quaternary carbon‐containing molecules through an innovative and distinctive disconnection approach. [ABSTRACT FROM AUTHOR]

: In order to solve the problems that wood dyeing consumes a lot of energy in industry and the color fastness of dyed veneer is poor, starting from improving the binding fastness of poplar to dye, the interaction between poplar and dye was enhanced by etherification modification of wood fiber. The wood fiber was grafted with positive quaternary ammonium salt group, which interacted with dye through ionic bond, and the dyed poplar veneer with high color fastness was successfully prepared at normal temperature. A large number of dye particles were uniformly deposited on wood pits and vessels. The crystalline morphology of cellulose did not change during the modification, and the crystallinity of dyed veneer increased to some extent. The new absorption peaks and the change of valence state of N element appeared in the dyed veneer, which confirmed that wood and dye were bonded by ionic bond. The ΔE (total chromatic aberration) and dye-uptake were increased by 5. 607 and17. 38%, respectively, compared with traditional boiling dyeing. The light fastness was excellent, when exposed to light for 24 hours, ΔE was 7. 702±0. 625. The bonding strength was high, the ΔE before and after washing and the absorbance of washed solution were 16. 97% and 5. 19% of the traditional dyed veneer, respectively. The results of this study provided an idea for solving the problems of high temperature of wood dyeing and low light fastness of acid dye dyed wood in actual production. [ABSTRACT FROM AUTHOR]

In this study, the use of anionic polymerization for the synthesis of living poly(dimethylsiloxane) or PDMS-Li+, as well as poly(2-vinylpyridine) or P2VP-Li+ homopolymers, and the subsequent use of chlorosilane chemistry in order for the two blocks to be covalently joined leading to PDMS-b-P2VP copolymers is proposed. High vacuum manipulations enabled the synthesis of well-defined materials with different molecular weights ( Μ ¯ n , from 9.8 to 36.0 kg/mol) and volume fraction ratios (φ, from 0.15 to 0.67). The  Μ ¯ n  values, dispersity indices, and composition were determined through membrane/vapor pressure osmometry (MO/VPO), size exclusion chromatography (SEC), and proton nuclear magnetic resonance spectroscopy (1H NMR), respectively, while the thermal transitions were determined via differential scanning calorimetry (DSC). The morphological characterization results suggested that for common composition ratios, lamellar, cylindrical, and spherical phases with domain periodicities ranging from approximately 15 to 39 nm are formed. A post-polymerization chemical modification reaction to quaternize the nitrogen atom in some of the P2VP monomeric units in the copolymer with the highest P2VP content, and the additional characterizations through 1H NMR, infrared spectroscopy, DSC, and contact angle are reported. The synthesis, characterization, and quaternization of the copolymer structure are important findings toward the preparation of functional materials with enhanced properties suitable for various nanotechnology applications. [ABSTRACT FROM AUTHOR]

Rechargeable aluminium (Al) batteries (RABs) have long-been pursued due to the high sustainability and three-electron-transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al-amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3 N.+ or R4 N+ ) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al-amine battery exhibits a high reversible capacity of 135 mAh g-1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2 %. Moreover, the Al-amine battery shows excellent stability against self-discharge, far beyond conventional Al-graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance.

In this work, we present the modification of a medical-grade silicone catheter with the N-vinylimidazole monomer using the grafting-from method at room temperature and induced by gamma rays. The catheters were modified by varying the monomer concentration (20–100 vol%) and the irradiation dose (20–100 kGy). Unlike the pristine material, the grafted poly(N-vinylimidazole) chains provided the catheter with hydrophilicity and pH response. This change allowed for the functionalization of the catheters to endow it with antimicrobial features. Thus, the quaternization of amines with iodomethane and bromoethane was performed, as well as the immobilization of silver and ampicillin. The inhibitory capacity of these materials, functionalized with antimicrobial agents, was challenged against Escherichia coli and Staphylococcus aureus strains, showing variable results, where loaded ampicillin was amply better at eliminating bacteria.

Dimethyl sulfate (DMS) is a quarternizing agent for esteramine used for the synthesis of esterquat. To date there is no reliable published method for quantification of DMS in palm‐based esterquat. Esterquat is used in the formulation of personal care and textile cleaning. The process of quaternization is usually incomplete and there will be unreacted DMS. This work presents a new simple method involving solvent extraction of DMS followed by analysis with gas chromatography–mass spectrometry detector to quantify the unreacted DMS. This method was validated as per International Council for Harmonization requirements. This novel method showed good repeatability (relative standard deviation [RSD] < 5%) and inter‐day with different analyst reproducibility (RSD < 5%). The limits of detection and quantification were 5 and 10 μg mL−1, respectively. The accuracy of the method was evaluated by the analysis of spiked samples and it was found that good recovery was found at spiking levels of 20, 30, and 50 μg mL−1 with % recovery falling within the 80%–120% acceptable limit. However, at 10 μg mL−1, the percentage recovery was slightly below the recommended limit. [ABSTRACT FROM AUTHOR]

A new polyacetylene-based polyelectrolyte with the ferrocene-containing pyridinium substituents was synthesized by the quaternization polymerization of 2-ethynylpyridine using (6-bromo-1-oxohexyl)ferrocene. The analysis results on the chemical structure of the resulting polymer revealed that it contains the conjugated polymer backbone system with the bulky N-(6-ferrocenyl-6-oxohexyl)pyridinium bromide substituents. The absorption spectrum exhibited the maximum peak of 519 nm which comes from the π → π∗ transition of the conjugated polyene group. The overall redox current shape showed irreversible results and the related values were very stable in the range of −1.5 V to 1.5 V under up to 50 cycles. The oxidation peak value was 0.5 V and 1.25 V and the reduction peak value was −1.3 V. [ABSTRACT FROM AUTHOR]

Peri-implantitis is a major cause of dental implant failure. This disease is an inflammation of the tissues surrounding the implant, and, while the cause is multi-factorial, bacteria is the main culprit in initiating an inflammatory reaction. Dental implants with silicon carbonitride (SiCN) coatings have several potential advantages over traditional titanium implants, but their antibacterial efficiency has not yet been evaluated. The purpose of this study was to determine the anti-bacterial potential of SiCN by modifying the surface of SiCN-coated implants to have a positive charge on the nitrogen atoms through the quaternization of the surface atoms. The changes in surface chemistry were confirmed using contact angle measurement and XPS analysis. The modified SiCN surfaces were inoculated with Streptococcus mutans (S. mutans) and compared with a silicon control. The cultured bacterial colonies for the experimental group were 80% less than the control silicon surface. Fluorescent microscopy with live bacteria staining demonstrated significantly reduced bacterial coverage after 3 and 7 days of incubation. Scanning electron microscopy (SEM) was used to visualize the coated surfaces after bacterial inoculation, and the mechanism for the antibacterial properties of the quaternized SiCN was confirmed by observing ruptured bacteria membrane along the surface. [ABSTRACT FROM AUTHOR]

Water-soluble chlorin e6 cationic derivatives with one and two galactose fragments at the quaternized nitrogen atom were synthesized, and the dark and photoinduced cytotoxicity of the obtained compounds was evaluated. [ABSTRACT FROM AUTHOR]

The applicability of cotton-bleached soda pulp (C-BSP) was investigated as a raw material for manufacturing cationic nano-fibrillated cellulose (NFC) via quaternization of anionic NFC using glycidyl-trimethyl-ammonium chloride (GMA). The anionic NFC was prepared by beating and micro-grinding C-BSP, and quaternization was performed post treatment to induce a charge reversal in anionic NFC. The characteristics of cationic NFC manufactured using C-BSP and hardwood-bleached kraft pulp (Hw-BKP) as a control were analyzed. Relatively higher mechanical energy was required to prepare anionic NFC from C-BSP than that from Hw-BKP. Fourier transform infrared and zeta potential analyses results showed that quaternization by GMA post treatment electrostatically induced charge reversal in anionic NFC. However, GMA did not affect the fiber width and viscosity of the cationic NFCs. It was found that cationic NFC could be manufactured via quaternization of anionic NFC manufactured from C-BSP using less GMA than that for Hw-BKP.

Radical polymerization reactions were employed to synthesize poly(2-acrylamido-2-methyl-1-propanesulfonic acid -co-1-vinylimidazole), hydrogels at neutral and acidic reaction conditions. The results of Fourier Transform Infrared (FT-IR) spectroscopy and scanning electron microscopy spectroscopy confirmed the chemical composition of the synthesized hydrogels. Loading Ag into hydrogels, removing loosely-bound Ag ions, and reducing Ag ions with sodium borohydride (NaBH4) were used to construct p(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag. Metal nanoparticles embedded p(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag were visualized by high resolution X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray. FT-IR spectroscopy and HR-XPS demonstrated that the interaction of network heteroatoms with Ag nanoparticles was responsible for stabilizing silver nanoparticles. Atomic absorption spectroscopy was also employed to measure the concentrations of metals in all compounds. P(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag composites were used as catalyst in the oxidation of alcohols by emphasizing the effects of different parameters such as oxidant, substituent effect, etc. The prepared porous hydrogels and related composites were also utilized in the adsorption of Benzyl alcohol from aqueous solutions. P(AMPS-Na+-co-VIm) and its composite has better performance than p(AMPS-H+-co-VIm) and p(AMPS-H+-co-VIm)-Ag. Because, absorption capacity is increased with an increase in the high porosity and it is depending on porous size and shapes. In continue, quaterniztion effect by 1,4-dibromobutane on catalytic performance of nano-composites was investigated. The results confirmed the easy separation of the prepared catalysts from the reaction media. Moreover, the catalysts could efficiently be recycled four times without losing their quality. It was also proved that the catalysts were recyclable, durable, and leaching-resistant. [ABSTRACT FROM AUTHOR]

A polymeric adsorbent for removal of hexavalent chromium (Cr(VI)) ions was developed by the photografting of 2-(dimethylamino)ethyl methacrylate (DMAEMA) to a polyethylene (PE) mesh and subsequent quaternization with iodoalkanes of different alkyl chain lengths. The grafting of DMAEMA and subsequent quaternization were verified by the FT-IR and XPS measurements. The Cr(VI) ion adsorption capacity of the DMAEMA-grafted PE meshes had the maximum value at the grafted amount of 2.6 mmol/g in a 0.20 mM K2Cr2O7 solution at pH 3.0 and 30°C. The adsorption behaviour obeyed the pseudo-second order kinetic model and well expressed by Langmuir isotherm. These results suggest that the Cr(VI) ion adsorption occurs through the electrostatic interaction mainly between protonated dimethylamino groups and hydrochromate (HCrO4-) ions. The adsorption capacity of the quaternized PE-g-PDMAEMA meshes increased with an increase in the degree of quaternization and/or the alkyl chain length of the iodoalkanes used and the maximum adsorption ratio was obtained at the degree of quaternization of 54.2% for the iodoheptane-quaternized PE-g-PDMAEMA (PE-g-QC7PDMAEMA) mesh. This value was about 1.86 times higher than that of the PE-g-PDAMEMA mesh. Cr(VI) ions were successfully desorbed from the PE-g-PDMAEMA and PE-g-QC7PDMAEMA meshes in eluents such as NaOH, NaCl, and NH4Cl. In 0.50 M NaCl, 0.10 M NH4Cl, and 0.50 mM NaOH, the adsorption and desorption process was repeatedly performed without any considerable decrease and the desorption behaviour obeyed the pseudo-second order kinetic model. These results emphasise that the PE-g-PDMAEMA meshes and their quaternized products can be applied as an adsorbent for Cr(VI) ions. [ABSTRACT FROM AUTHOR]

Dye is an anionic common pollutant in industrial wastewater and poses a great threat to the environment and human health. Owing to its advantageous adsorption capacity, nanocellulose is widely used for wastewater treatment. The cell walls of Chlorella mainly comprise cellulose instead of lignin. In this study, residual Chlorella-based cellulose nanofiber (CNF) and cationic cellulose nanofiber (CCNF) with surface quaternization were prepared through homogenization. Moreover, Congo red (CR) was used as a model dye to measure the adsorption capacity of CNF and CCNF. The adsorption capacity was almost saturated when CNF and CCNF contacted CR for 100 min, and the adsorption kinetics coincided with the pseudo-secondary kinetics model. The initial concentration of CR considerably affected its adsorption on CNF and CCNF. Below the initial concentration of 40 mg/g, the adsorption on CNF and CCNF considerably increased with the increase in the initial concentration of CR. Based on the sorption isotherms analysis of CNF and CCNF, the Langmuir model fitted best with the experimental data. Thus, CNF and CCNF surfaces were uniform, and monolayer adsorption occurred. The adsorption of CR on CNF and CCNF was greatly affected by the pH value, and the acidic medium favored the adsorption of CR (especially for CCNF). CCNF showed a more advantageous adsorption capacity, with a maximum value of 1657.89 mg/g, compared to that of CNF (190.0 mg/g). According to the findings of this study, residual Chlorella-based CCNF could be a very promising adsorbent candidate for removing anionic dyes from wastewater. [ABSTRACT FROM AUTHOR]

In this study, two kinds of novel anion exchange membranes based on chitosan backbone are obtained. N-4-Methylpiperidinechitosan (NMPCS) and quaternized N-[(2-hydroxyl-3-piperidine)propyl]chitosan (QNHPPCS) are synthesized by the reaction of chitosan with 1-methyl-4-piperidone and 2,3-epoxypropylpiperidineammonium chloride, respectively, and the piperidinium groups of NMPCS and QNHPPCS are grafted to chitosan backbone by non-N and N site, respectively. 1H NMR and FT-IR tests prove that 1-methyl-4-piperidone and 2,3-epoxypropylpiperidineammonium chloride successfully react with chitosan. 3-Glycidoxypropyltrimethoxysilane (KH560) is used for cross-linking, after cross-linking, the tensile strength of cross-linked quaternized N-4-methylpiperidinechitosan (CQNMPCS) and cross-linked quaternized N-[(2-hydroxyl-3-piperidine)propyl]chitosan (CQNHPPCS) can both reach 8 MPa, and the membranes are not excessive swelling in water. The ion exchange capacity (IEC) of CQNMPCS and CQNHPPCS can reach up to 2.28 mmol·g−1 and 1.36 mmol·g−1, respectively. XRD and DSC tests evaluate aggregate structure change of chitosan modification; the graft modification destroys the semi-crystalline structure of chitosan and results in low mechanical strength. The ion conductivity of CQNMPCS and CQNHPPCS can reach up to 30.6 mS·cm−1 and 25.5 mS·cm−1, respectively. After being immersed in 8 mol·L−1 KOH solution, the ion conductivity retention of CQNMPCS and CQNHPPCS can both reach 90%, and the CQNMPCS is more alkaline resistant. These results indicate that the prepared chitosan-based anion exchange membranes are promising materials for fuel cell application. [ABSTRACT FROM AUTHOR]

Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC) to explore a potential use of them as an adsorbent for removal of humic acid (HA) from aqueous medium. The introduction of quaternary ammonium groups was confirmed by FT-IR and XPS analysis. The content of introduced quaternary ammonium groups increased with an increase in the GTMAC concentration. The adsorption capacity increased with a decrease in the initial pH value and attained the maximum value at pH 3 and increased with an increase in the content of quaternary ammonium groups. The removal % increased with the dose of quaternized cellulose beads at both pH 3.0 and 6.0. The adsorption process obeyed the pseudo-second order kinetic model and exhibited a better fit to the Langmuir isotherm model, suggesting that the adsorption of HA is accomplished through the electrostatic interaction between a quaternary ammonium group introduced and a dissociated carboxy group of a HA molecule. The maximum adsorption capacity obtained in this study is comparable to or higher than those published by other articles. HA loaded was completely released to NaOH solutions at higher than 100 mM to regenerate the quaternized cellulose beads. The above-mentioned results clearly show that the quaternized cellulose beads prepared in this study can be used as a regenerable adsorbent with high capacity for removal of HA from aqueous medium.

A multi-layer barrier coating technology was developed using nano-fibrillated cellulose (NFC) alongside a hydrophobic, paraffin-free biowax for manufacturing an eco-friendly functional packaging paper. Anionic NFC was prepared by isolating hardwood-bleached kraft pulp (Hw-BKP) using a micro-grinder, and cationic NFC was prepared by the quaternization reaction of the anionic NFC. Thereafter, a three-layer barrier-coated paper was manufactured using cationic and anionic NFCs and biowax. The air permeability and water vapor transmission rate (WVTR) of the three-layer barrier-coated paper were measured, and its coverage and coating layer structure were observed by scanning electron microscopy (SEM). The air permeability of the three-layer barrier-coated paper was more than 15,000 s and those WVTR was 67.1 g/m2/day. Its coverage and surface were considerably uniform and smooth. Thick and effective barrier coating layers were formed as indicated by SEM images. Therefore, it was concluded that a multi-layer barrier-coated paper with considerably high barrier properties could be produced using cationic and anionic NFCs with high gas barrier properties and biowax with high moisture barrier properties. Further, the structure could be used as a functional packaging paper with high barrier properties.

Poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-1-vinylimidazole), hydrogels were synthesized via free radical polymerization reaction at different conditions and modified with di-alkyl halide. P(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag were prepared by reducing Ag(CH3COO) salts loaded into p(AMPS-Na+-co-VIm) and p(AMPS-H+-co-VIm) hydrogels and then reduced by NaBH4. Metal nanoparticles embedded p(AMPS-Na+-co-VIm)-Ag and p(AMPS-H+-co-VIm)-Ag were visualized by high resolution X-ray photoelectron spectroscopy (HRXPS) and transmission electron microscopy (TEM). The prepared porous hydrogels and related composites were utilized in the adsorption of Rhodamine B from aqueous solutions. Among non-quaternized hydrogels, p(AMPS-Na+-co-VIm) and its composite outperformed p(AMPS-H+-co-VIm) and p(AMPS-H+-co-VIm)-Ag. since high porosity increases absorption capacity, which depends on the size and shape of the pores. In addition, the effect of 1,4-dibromobutane quaternization on the catalytic performance of nano-composites was investigated. Finally, the catalyst was easily recovered from the reaction medium and re-used for a further four runs without significant loss of activity. The durability of the catalyst structure without leaching was confirmed by FT-IR spectra and atomic absorption spectroscopy, respectively.

The applicability of cotton-bleached soda pulp (C-BSP) was investigated as a raw material for manufacturing cationic nano-fibrillated cellulose (NFC) via quaternization of anionic NFC using glycidyl-trimethyl-ammonium chloride (GMA). The anionic NFC was prepared by beating and microgrinding C-BSP, and quaternization was performed post treatment to induce a charge reversal in anionic NFC. The characteristics of cationic NFC manufactured using C-BSP and hardwood-bleached kraft pulp (Hw-BKP) as a control were analyzed. Relatively higher mechanical energy was required to prepare anionic NFC from C-BSP than that from Hw-BKP. Fourier transform infrared and zeta potential analyses results showed that quaternization by GMA post treatment electrostatically induced charge reversal in anionic NFC. However, GMA did not affect the fiber width and viscosity of the cationic NFCs. It was found that cationic NFC could be manufactured via quaternization of anionic NFC manufactured from CBSP using less GMA than that for Hw-BKP. [ABSTRACT FROM AUTHOR]

In this work, the synthesis and the stimuli-responsive self-assembly behavior of novel double-hydrophilic poly(2-(dimethylamino)ethyl methacrylate-co-(oligo ethylene glycol)methacrylate) random copolymers and their chemically modified derivatives are presented. The synthesis of P(DMAEMA-co-OEGMA) copolymers of different DMAEMA mass compositions was successfully conducted through RAFT polymerization, further followed by the hydrophilic/hydrophobic quaternization with methyl iodide (CH3I), 1-iodohexane (C6H13I), and 1-iodododecane (C12H25I). The tertiary and quaternary amines are randomly arranged within the DMAEMA segment, responding thus to pH, temperature, and salt alterations in aqueous solutions. Light scattering techniques elucidated the intramolecular self-folding and intermolecular self-assembly of polymer chains of P(DMAEMA-co-OEGMA) copolymers upon exposure to different pHs and temperatures. Q(P(DMAEMA-co-OEGMA)) cationic polyelectrolytes demonstrated moderate response to pH, temperature, and ionic strength as a result of the permanent hydrophilic/hydrophobic profile, closely connected with the attached alkyl chains and the quaternization degree. Moreover, fluorescence spectroscopy measurements confirmed the internal micropolarity and the picture of the aggregate inner structure. [ABSTRACT FROM AUTHOR]

Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC) to explore a potential use of them as an adsorbent for removal of humic acid (HA) from aqueous medium. The introduction of quaternary ammonium groups was confirmed by FT-IR and XPS analysis. The content of introduced quaternary ammonium groups increased with an increase in the GTMAC concentration. The adsorption capacity increased with a decrease in the initial pH value and attained the maximum value at pH 3 and increased with an increase in the content of quaternary ammonium groups. The removal % increased with the dose of quaternized cellulose beads at both pH 3.0 and 6.0. The adsorption process obeyed the pseudo-second order kinetic model and exhibited a better fit to the Langmuir isotherm model, suggesting that the adsorption of HA is accomplished through the electrostatic interaction between a quaternary ammonium group introduced and a dissociated carboxy group of a HA molecule. The maximum adsorption capacity obtained in this study is comparable to or higher than those published by other articles. HA loaded was completely released to NaOH solutions at higher than 100 mM to regenerate the quaternized cellulose beads. The above-mentioned results clearly show that the quaternized cellulose beads prepared in this study can be used as a regenerable adsorbent with high capacity for removal of HA from aqueous medium. [ABSTRACT FROM AUTHOR]

According to evidence in the literature, organic salts have an affinity for biological membranes that makes them easily absorbed into cells and capable of having a wide range of biological effects, such as broad antibacterial potential and anticancer activity. The present work describes the preparation of three organic salts with a common decyl-1,10-phenanthrolinium cation ([C22H25N2]+) differing in the anions (Br−, PF6− and (CF3SO2)2N−). The synthesis was confirmed using spectrometry methods (NMR (1H 13C, 19F, 31P), ESI MS, Uv-Vis), CHNSBr elemental and thermal analysis as well as conductivity measurements. In vitro biological activities were tested on two Gram-positive (Staphylococcus aureus (S. aureus), Streptococci pyogenes (S. pyogenes)) and two Gram-negative (Escherichia coli (E. Coli) and Klebsiellae pneumoniae (K. Pneumoniae)) bacteria and compared with a commercial antibiotic (Gentamicin). The salt with the halide anion demonstrated better inhibition activities than the commercially available gentamicin. Their ion-conductivity in ethanol was found to decrease in the order [C22H25N2][PF6], [C22H25N2][(CF3SO2)2N] and [C22H25N2]Br while, their thermal stability was found to increase in the order [C22H29N2]Br, [C22H29N2][PF6], and [C22H29N2][(CF3SO2)2N]. The minimum inhibitory concentration (MIC) values show that the salts could inhibit bacterial growth at concentrations as low as 50 μg/L. Passing the cytotoxicity investigations, these salts can be considered as alternative antibiotics in combating the emerging drug resisting bacteria.

SARS-CoV-2 caused a global pandemic with high transmission rates, even with widespread vaccination. In addition to isolation and prevention measures, it is important to find new solutions to inactivate the virus and prevent its viability on surfaces, such as clothing and face masks. Chitosan derivatives, with their antibacterial activity, biocompatibility, and non-toxicity, are a promising option for coating these components with virucidal materials. N-(2-hydroxypropryl)-3-trimethylammonium chloride, a quaternized chitosan derivative with degrees of substitution ranging from 59 to 93%, was synthesized. This derivative was used to coat cotton and polypropylene fabrics, such as face masks, without visibly affecting their morphology or filtering capacity. In vitro tests demonstrated that the coatings produced had high antiviral activity against coronavirus, with efficacy up to 99.99%, and were also bactericidal against E. coli and S. aureus. These results show that quaternized chitosan derivatives have great potential to be used as virucidal coatings, helping to prevent the spread of SARS-Cov-2 and other pathogens on surfaces, which can even be useful for the quick development of solutions for future pandemics.

Marine biological fouling is the undesirable accumulation on the surfaces of submerged objects and causes environmental and economic consequence to ships and marine facilities. However, traditional coatings achieve antifouling by releasing toxic heavy metal antifouling agents, causing ecological problems. And the static antifouling performance of self-polishing antifouling coating is not good. To overcome the shortcoming, a novel antifouling strategy to build a self-renewing multi-level microstructure on the coating surface was developed by dispersing GO-based quaternary polymer brushes in a self-polishing fluoro/silyl acrylate copolymer. Quaternized GO exhibits excellent dispersibility in the silyl-based acrylate copolymer. A dynamic self-renewing surface is realized for the coating via a self-polishing effect that exposes the filler inside the coating at the surface. The multi-level microstructure of the sharp edge of GO and quaternized "spear" structure destroys the cell wall of organisms. And a "water-shield" on amphoteric ion surface on quaternized GO inhibits adhesion of organisms. The antibacterial and anti-algae tests demonstrated the excellent antifouling effect of the coating at only 0.1% (mass) filler content, with anti-algae ratio against Nitzschia closterium (N. closterium), Phaeodactylum tricornutum (P. tricornutum) and Halamphora sp. of 83.7%, 52.4%, and 65.8%, respectively. The proposed preparation method is simple and potentially applicable to large-scale production for antifouling application. [Display omitted] • Multi-level microstructure was constructed for antifouling by quaternization-modified GO. • The coating exhibited a significant antifouling effect at only 0.1% (mass) filler content. • A GO surface killing-resistance mechanism is proposed for the first time. [ABSTRACT FROM AUTHOR]

Stimuli-responsive copolymers are of great interest for targeted drug delivery. This study reports on a controllable post-polymerization quaternization with 2-bromomethyl-4-fluorophenylboronic acid of the poly(4-vinyl pyridine) (P4VP) block of a common poly(styrene)-b-poly(4-vinyl pyridine)-b-poly(ethylene oxide) (SVE) triblock terpolymer in order to achieve a selective responsivity to various diols. For this purpose, a reproducible method was established for P4VP block quaternization at a defined ratio, confirming the reaction yield by 11B, 1H NMR. Then, a reproducible self-assembly protocol is designed for preparing stable micelles from functionalized stimuli-responsive triblock terpolymers, which are characterized by light scattering and by cryogenic transmission electron microscopy. In addition, UV-Vis spectroscopy is used to monitor the boron-ester bonding and hydrolysis with alizarin as a model drug and to study encapsulation and release of this drug, induced by sensing with three geminal diols: fructose, galactose and ascorbic acid. The obtained results show that only the latter, with the vicinal diol group on sp2-hybridized carbons, was efficient for alizarin release. Therefore, the post-polymerization method for triblock terpolymer functionalization presented in this study allows for preparation of specific stimuli-responsive systems with a high potential for targeted drug delivery, especially for cancer treatment. [ABSTRACT FROM AUTHOR]

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Heterocyclic electrophiles as small covalent fragments showed promising inhibitory activity on the antibacterial target MurA (UDP-N-acetylglucosamine 1-carboxyvinyltransferase, EC:2.5.1.7). Here, we report the second generation of heterocyclic electrophiles: the quaternized analogue of the heterocyclic covalent fragment library with improved reactivity and MurA inhibitory potency. Quantum chemical reaction barrier calculations, GSH (L-glutathione) reactivity assay, and thrombin counter screen were also used to demonstrate and explain the improved reactivity and selectivity of the N-methylated heterocycles and to compare the two generations of heterocyclic electrophiles. [ABSTRACT FROM AUTHOR]

Pistachio shell powder (PSP) was chemically modified using the quaternizing agent N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride, under strong alkaline conditions. In order to acquire a thorough understanding of their chemical and structural properties, samples were characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EXD), elemental analysis, X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) analysis. The characterization results showed that the quaternary ammonium groups were successfully grafted onto the PSP molecular structure and morphology of PSP has changed. The potential of quaternized pistachio shell powder (QPSP) in removing Acid Orange 7 (AO7) dye from aqueous solutions under batch conditions was investigated. Adsorption experiments were carried out as a function of initial solution pH, contact time, initial dye concentration, adsorbent dose, and salt concentration. Studies on the effect of pH revealed that initial solution pH had little effect on adsorption. The kinetic results showed that pseudo-second-order kinetic model adequately represented the adsorption of AO7 onto QPSP. Compared to the Freundlich isotherm model, the Langmuir isotherm model fitted well with the equilibrium data with high correlation coefficients. The maximum adsorption capacity of QPSP estimated from the Langmuir isotherm model was 215.5 mg∙g−1. It was also observed that QPSP showed excellent reusability that the value of adsorbed amount of AO7 onto QPSP decreased only by 3.0% of initial value after five consecutive adsorption–desorption cycles. This work indicated that QPSP could be used as an adsorbent to remove AO7 from aqueous media. [ABSTRACT FROM AUTHOR]

Glycidyltrimethylammonium chloride (GLYTAC) is an efficient quaternizing reagent, easy to synthesize, and causes lesser degradation to the polymer backbone than other reagents. Quaternization of guar gum was carried out using condensate of trimethylamine and epichlorohydrin as etherifying reagents adopting Taguchi's L9 orthogonal array design of experiment to optimize the reaction conditions to attain a higher degree of substitution (DS). The set of optimized levels of selected control factors are as follows; 2.5 mL and 1.2 g of condensate and sodium hydroxide respectively at 30 °C and time 6 h. The DS of the quaternized derivative prepared under optimized reaction conditions was determined as 0.046. The appearance of an additional signal at 3.06 ppm and 54.62 in 1H and 13C and the corresponding cross signal inHSQC (1H−13C) confirmed the synthesis of quaternized guar gum. The study demonstrated that Taguchi L9 orthogonal array is a reliable statistical approach for efficient and green synthesis of quaternized derivatives. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate nitrate sorption onto quaternary ammonium-functionalized poly(amidoamine) dendrimer generation 2.0 (q-PAMAM-G2). The physicochemical characteristics of the q-PAMAM-G2 were examined using field emission scanning electron microscopy, thermogravimetric analysis, electrophoretic light scattering spectrophotometry, elemental analysis, etc. Single-parameter sorption tests were performed under batch conditions to examine the nitrate sorption characteristics of the q-PAMAM-G2. According to a pH experiment, the q-PAMAM-G2 maintained a relatively stable nitrate sorption capacity at pH 2 to 10. X-ray photoelectron spectrometry analysis indicated a new peak for the NH4NO3 bond after nitrate sorption, confirming nitrate sorption to quaternary ammonium groups on the surface of the q-PAMAM-G2 through anion exchange. The kinetic data were best fit with the pseudo-second-order model, whereas the equilibrium data fitted well with the Langmuir isotherm, suggesting that nitrate sorption onto the q-PAMAM-G2 occurred through chemisorption. Multi-parameter sorption experiments (n = 32) were conducted with three input variables (adsorbent dose, initial nitrate concentration, and solution pH) and one output variable (nitrate removal rate). In response surface methodology (RSM) modeling, a quartic regression model (fourth-order polynomial equation) was developed to predict nitrate sorption onto the q-PAMAM-G2. In the artificial neural network (ANN) modeling, a model with a structure of 3:10:1 was derived to describe the nitrate sorption data. Additional multi-parameter experiments for nitrate sorption onto the q-PAMAM-G2 (n = 8) were conducted to further evaluate the developed models. The developed ANN model (R2 = 0.872) predicted better than did the RSM model (R2 = 0.790) for the additional multi-parameter experimental data. [ABSTRACT FROM AUTHOR]

Pervaporation offers unique advantages for desalination of hypersaline water using highly hydrophilic and selective membrane. Positively charged membrane is superior in repelling cations and preventing scaling through electrostatic repulsion. This study investigates the quaternization and crosslinking of block copolymer styrene-ethylene-butylene-styrene (SEBS) membrane and explores the potential of quaternized membrane for pervaporation desalination. A one-step immersion process was proposed to easily adjust the physicochemical properties of membrane using trimethylamine (TMA) and N , N , N ′, N ′-tetramethyl-1,6-hexanediamine (TMHDA) for ammonium grafting and crosslinking. Compared to the quaternization with TMA or TMHDA alone, the combination of TMA and TMHDA produces a synergistic effect, improving crosslinking efficiency and facilitating the grafting reaction. This results in high ion exchange capacity (IEC) values and a transformation of microphase separation structure with more interconnected hydrophilic domains. An ultrahigh water permeability coefficient of 0.6 × 106–1.2 × 106 Barrer and highly intrinsic salt rejection were obtained in treating 3.5–20 wt% NaCl solution. The thin film composite QEBS/nylon membranes showed a superior water flux of 116.5 kg·m−2·h−1 and salt rejection of >99.99 % in desalinating 5 wt% NaCl solution at 85 °C. Additionally, the membrane exhibited excellent long-term performance stability and resistance to acid and alkali environment, showing great potential for desalination of hypersaline water. • SEBS membrane was quaternized and crosslinked through a one-step immersion method. • The microscopic structure of membrane was adjusted by quantities of TMA and TMHDA. • The membrane shows outstanding water permeability and salt rejection in pervaporation. • The membrane has excellent performance stability and acid and alkali resistance. [ABSTRACT FROM AUTHOR]

Infectious disease caused by methicillin-resistant Staphylococcus aureus (MRSA) seriously threatens public health. The design of antimicrobial peptide mimics (AMPMs) based on natural products (NPs) is a new strategy to kill MRSA and slow the development of drug resistance recently. Here, we reported the design and synthesis of novel AMPMs based on harmane skeleton. Notably, compound 9b exhibited comparable or even better anti-MRSA activity in vitro and in vivo with minimum inhibitory concentration (MIC) of 0.5–2 μg/mL than the positive drug vancomycin. The highly active compound 9b not only showed low cytotoxicity, no obvious hemolysis and good plasma stability, but also presented low tendency of developing resistance. Anti-MRSA mechanism revealed that compound 9b could destroy cell wall structure by interacting with lipoteichoic acid and peptidoglycan, cause membrane damage by depolarization, increased permeability and destructed integrity, reduce cell metabolic activity by binding to lactate dehydrogenase (LDH), interfere cellular redox homeostasis, and bind to DNA. Overall, compound 9b killed the MRSA by multi-target mechanism, which provide a promising light for combating the growing MRSA resistance. [Display omitted] • Quaternized AMPMs based on harmane are designed and synthesized. • Compound 9b possess remarkable anti-MRSA effects in vitro and in vivo. • Compound 9b slow down the development of drug resistance by multi-target mechanism. [ABSTRACT FROM AUTHOR]

• Hemp fiber with optimal adsorption capacity and optimal fouling resistance of amidoxime-quaternized polyethyleneimine (HFAO-QPEI) were prepared using simple fiber surface modification grafting. • HFAO-QPEI exhibits excellent uranium selectivity and recyclability. • Quaternization gives HFAO-QPEI significant biofouling resistance, especially inhibiting the adhesion of mussels. • DFT calculation results indicate that the HFAO-QPEI-U mode exhibits the most stable structure. Nuclear energy plays a key role in the global energy supply. The adsorption and extraction of uranium from seawater is key to the rapid development of nuclear energy. In this paper, quaternary aminated polyethyleneimine/amidoxime-modified hemp fiber (HFAO-QPEI) with high adsorption capacity and anti-biofouling properties were successfully synthesized by immersion and hydrothermal methods. Upon systematic evaluation, HFAO-QPEI possessed high adsorption capacity and good reusability with fast adsorption kinetics, as well as good adsorption selectivity and affinity for uranyl ions. Furthermore, HFAO-QPEI not only reached a maximum adsorption capacity of 364.7 mg/g but also demonstrated a short adsorption equilibrium time of 200 min. In contrast, HFAO-QPEI demonstrated high selectivity for uranyl ions, removing up to 95.1 % of uranium with K d value of 4.69 × 104 mL/g, which was 256.3 times greater than that of hemp fiber (HF). After the fifth adsorption–desorption cycle, the recovery of U(VI) was 91.38 %. DFT calculations proved that HFAO-QPEI-U was the most stable model. The quaternary ammonium salt functionalization not only makes HFAO-QPEI have excellent anti-biofouling ability (anti-diatom rate up to 87.22 %, anti-bacterial rate up to 97 % or more, anti-adhesion of large fouling organisms mussels with a certain effect), but also modifies its surface charge, making it more suitable for the marine environment. In addition, HFAO-QPEI showed a high adsorption capacity of 2.45 mg/g in natural seawater. The results suggest that the HFAO-QPEI adsorbent holds great promise for extracting uranium from seawater. [ABSTRACT FROM AUTHOR]

Degradable block copolymers are considered as ideal templates to prepare porous membranes with tunable nanostructure. However, most of these templates are hydrophobic and it remains a challenge to make nanoporous and charged membranes using such templates that contain a sacrificial block through phase inversion. Herein, block copolymers poly(ε-caprolactone)- b -poly(4-vinyl pyridine) have served as cross-linkable and degradable templates to prepare porous and dense membranes via non-solvent induced phase separation (NIPS) or solvent evaporation-induced phase separation (SIPS). During NIPS, the prepared membranes showed a dense skin and finger-like or sponge-like sublayer. By controlling the quaternization and degradation of templates, the permeance of pure water and molecular weight cut-off performance tuning were achieved. The above ultrafiltration membranes with well-defined pores exhibited excellent rejection ability towards different dyes based on size exclusion and Donnan effect. Moreover, after being treated with NaOH solution, the membranes fabricated via SIPS showed a unique change from dense to hollow cross-sectional structure, which also demonstrated promising electrodialysis desalination performance and electrodialysis stability. A schematic graph illustrating the preparation of composite membranes with tunable pore morphology, which used cross-linkable and degradable templates. [Display omitted] • Effect of block copolymer templates on membrane structure was studied. • Characterized film structure before and after hydrolysis of polyester domains. • The membranes via NIPS exhibit tunable pore-size and dye interception performance. • The membranes via SIPS feature excellent desalination ability and stability. [ABSTRACT FROM AUTHOR]

Chemical modification is a reliable and efficient strategy for designing cellulose-based functional materials. Herein, porous quaternized cellulose beads (QCBs) as cationic superabsorbent were fabricated by homogeneous in-situ chemical grafting cellulose molecular chains with glycidyl trimethylammonium chloride (GTAC) in tetraethylammonium hydroxide (TEAOH)/urea aqueous solution followed by acetic acid induced regeneration. The influence of GTAC dosage on the physicochemical-structural properties of cationic QCBs was deeply investigated. Results revealed that cotton liner could well-dissolved in TEAOH/urea aqueous solution, leading to a homogeneous and efficient quaternization medium for cellulose, thereby giving the high DS and positive charge density for quaternized cellulose. NMR results demonstrated the main substitution of GTAC groups at 2-OH and 6-OH positions of the cellulose chains during quaternization reaction. With increasing GTAC dosage, the network skeleton of QCBs gradually transformed from thick fibrils to thin aggregates, as well as enhanced pore volumes and hydrophilicity. Accordingly, QCBs-1.5 with high pore volume (99.70 cm3/g) exhibited excellent absorption capacity and efficiency, absorbing 122.32 g of water and 0.45 g of moisture per gram of the beads in 20 min. This work not only offers a simple strategy for the homogeneous quaternization modification of cellulose, but also provides a porous cellulose-based cationic superabsorbent material. [Display omitted] [ABSTRACT FROM AUTHOR]

• Polycationic nanoparticles incorporated to the pore walls of the cryogel. • The cryogels exhibited inherent antibacterial activity against E. coli and S. aureus. • The cryogels possessed superior biocompatibility and super-fast swelling. Inherently antibacterial polycations have been of interest in the pursuit of overcoming antibiotic resistance. In this study, we have prepared a new cryogel system incorporating polycationic nanoparticles composed of 4-vinylpyridine (4VP) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA), which possess inherent antibacterial properties. The incorporated polycationic nanoparticles were successfully attached to the pore wall surfaces of the cryogels with quaternization reaction. While the cryogel's pore size was 50 ± 10 μm, the diameter of the nanoparticles attached on the pore surfaces was 150 ± 16 nm. The prepared nanoparticle-integrated cryogels revealed a high biocompatibility on L929 mouse fibroblast cells and antibacterial activity against both E. coli and S. aureus bacteria. These cryogels have potential in numerous applications including antibacterial surfaces, wound dressings and tissue engineering. [ABSTRACT FROM AUTHOR]

Peri-implantitis is a major cause of dental implant failure. This disease is an inflammation of the tissues surrounding the implant, and, while the cause is multi-factorial, bacteria is the main culprit in initiating an inflammatory reaction. Dental implants with silicon carbonitride (SiCN) coatings have several potential advantages over traditional titanium implants, but their antibacterial efficiency has not yet been evaluated. The purpose of this study was to determine the anti-bacterial potential of SiCN by modifying the surface of SiCN-coated implants to have a positive charge on the nitrogen atoms through the quaternization of the surface atoms. The changes in surface chemistry were confirmed using contact angle measurement and XPS analysis. The modified SiCN surfaces were inoculated with Streptococcus mutans (S. mutans) and compared with a silicon control. The cultured bacterial colonies for the experimental group were 80% less than the control silicon surface. Fluorescent microscopy with live bacteria staining demonstrated significantly reduced bacterial coverage after 3 and 7 days of incubation. Scanning electron microscopy (SEM) was used to visualize the coated surfaces after bacterial inoculation, and the mechanism for the antibacterial properties of the quaternized SiCN was confirmed by observing ruptured bacteria membrane along the surface.

A multi-layer barrier coating technology was developed using nanofibrillated cellulose (NFC) alongside a hydrophobic, paraffin-free biowax for manufacturing an eco-friendly functional packaging paper. Anionic NFC was prepared by isolating hardwood-bleached kraft pulp (Hw-BKP) using a micro-grinder, and cationic NFC was prepared by the quaternization reaction of the anionic NFC. Thereafter, a three-layer barrier-coated paper was manufactured using cationic and anionic NFCs and biowax. The air permeability and water vapor transmission rate (WVTR) of the three-layer barrier-coated paper were measured, and its coverage and coating layer structure were observed by scanning electron microscopy (SEM). The air permeability of the three-layer barrier-coated paper was more than 15,000 s and those WVTR was 67.1 g/m² /day. Its coverage and surface were considerably uniform and smooth. Thick and effective barrier coating layers were formed as indicated by SEM images. Therefore, it was concluded that a multi-layer barrier-coated paper with considerably high barrier properties could be produced using cationic and anionic NFCs with high gas barrier properties and biowax with high moisture barrier properties. Further, the structure could be used as a functional packaging paper with high barrier properties. [ABSTRACT FROM AUTHOR]

Soy protein isolate (SPI) is green, high-yield natural plant protein, which is widely applied in industry (packing material and adhesives) and tissue engineering. It is meaningful to improve the antibacterial property of soy protein isolate to fabricate versatile safe products to meet people's requirements. In this study, quaternized soy protein isolate (QSPI) was synthesized by the reaction between 2,3-epoxypropyltrimethylammonium chloride (EPTMAC) and SPI. The positive charged (17.8 ± 0.23 mV) quaternary ammonium groups endow the QSPI with superior antibacterial properties against multiple bacteria in vitro and in vivo. Notably, QSPI maintains its good biocompatibility and promotes bacterial-infected wound healing in rat models. Furthermore, QSPI possesses superior water solubility in a broad pH range than raw SPI. Altogether, this soy protein isolate derivative with antibacterial property and superior water solubility may extend the application of SPI in industry and tissue engineering. [ABSTRACT FROM AUTHOR]

Limited research exists on how the structure of quaternary ammonium salt (QAS) affects the electrostatic attraction and hydroxyl reactivity of cationic cotton, which strongly affects reactive dye adsorption, diffusion, and fixation. Thus, in our work, the effects of QAS structure on the electrostatic attraction, hydroxyl reactivity, and dyeing properties were investigated. The intensity at 402.5 eV (-N + (CH 3 ) 3 ) in the XPS rose from 34 % to 70 % as the QAS alkyl chain length increased from 4 to 18 carbon atoms, signifying an enhancement of the positive charge and electrostatic attraction between reactive dye and QAS modified cotton. However, molecular dynamic (MD) simulations of the QAS-modified cotton with octadecyl chains revealed that the reactive dye demonstrated slower molecular mobility compared to the untreated cotton. This is not conducive to the diffusion and fixation of reactive dyes. The QAS-modified cotton with hexyl chains not only alters the activity of hydroxyl at the 6th but also generates additional hydroxyl at the β-position that contributes to enhancing the improvement of fixation through Gaussian simulations. Therefore, cationic cotton treated with 60 g/L of (3-chloro-2-hydroxypropyl)-dimethyl-octadecylazanium chloride (CT-8) exhibits superior dye uptake levels (91.84 %), K/S values (13.10), and dye fixation percent (88.38 %)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The increasing presence of pharmaceuticals and personal care products (PPCPs) in aquatic systems pose significant environmental concerns. This study addresses this issue by synthesizing quaternized mesoporous SBA-15 (Q SBA ) with varied alkyl chain lengths of C1Q SBA , C8Q SBA , and C18Q SBA . Q SBA utilizes dual mechanisms: hydrophobic interactions via the alkyl chain and electrostatic attraction/ion exchange via the ammonium group. Diclofenac (DCF) and acetaminophen (ACT) were selected as target PPCPs due to their contrasting dissociation properties and hydrophobicity, which are the main characteristics of PPCPs. The adsorption of DCF and ACT revealed that longer alkyl chains enhanced the adsorption capacity of ACT through hydrophobic interactions, whereas dissociated DCF (DCF - ) adsorption was superior owing to its high hydrophobicity (log Kow = 4.5) and electrostatic attraction. pH levels between 6 and 8 resulted in a high affinity for DCF - . Notably, among the three alkyl chains, only C18Q SBA exhibited the most effective adsorption for DCF - . These PPCPs adsorption trends were confirmed through molecular simulations of adsorption under conditions in which competing ions coexisted. The molecular simulations show that while DCF - has lower adsorption energy than Cl - , OH - , and H 3 O + ions in Q SBA , enhancing its adsorption under various pH conditions. Conversely, ACT exhibits a higher adsorption energy, which reduces its adsorption efficiency. This suggests the potential application of Q SBA with long alkyl chains in the treatment of highly hydrophobic and negatively charged PPCPs. Furthermore, this study emphasizes the importance of simulating adsorption under competing ion conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Currently, an important ecological problem is environmental pollution and its negative impact on living organisms, the consequences of which are deterioration in general health and the manifestation of various diseases, poisoning, endo- and exotoxicosis. Enterosorption method was proposed as a promising method for removing toxic substances from the living organisms using enterosorbents which can absorb various toxic substances of endogenous and exogenous nature in the lumen of the gastrointestinal tract. It has been proposed to use polymer-containing enterosorbents for eliminating of heavy metals from the organism. The purpose of this research was to synthesize a quaternized derivative of chitosan, specifically N-(2-hydroxybenzyl)-N-ethyl-N-methyl chitosan chloride (Q-CHS). The synthesis of Q-CHS involved the formation of a Schiff base, followed by the quaternization of the amino group of chitosan (CHS). The structures of both pure CHS and quaternized CHS were studied using various physico-chemical methods, including FTIR, NMR, XRD, SEM, DSC and TGA analyses in order to determine the structure and confirm the formation of the final product., (Copyright © 2024 Elsevier Ltd. All rights reserved.)