Ammonium Research Articles

ANTIVIRAL TEXTILES AND ANTIVIRAL ACTIVITY TESTING - THE USE OF BACTERIOPHAGE SURROGATE FOR ANTIVIRAL ACTIVITY TESTING

The risk of dissemination of highly contagious viral diseases (as COVID-19, Ebola) led in the increasing need to develop functional textiles and surfaces with antiviral effect. Antiviral textiles are designed to reduce the viability and infectivity of viruses on their surfaces and by this way to reduce the cases of infection (including re-infection or cross-infection with contaminated textiles). Different antiviral agents and diverse techniques of their application are used for functionalized textiles manufacturing. The most often used antivirals are metallic and ionic silver and copper, iron oxide, quaternary ammonium salts. The aim of the process is to prepare textiles with long-term durable finishing effective in viral activity inhibition. The basic step of functionalized antiviral textiles development is antiviral effectivity testing. The safe method of testing with the use of Phi6 bacteriophage, SARS-CoV-2 and Ebola virus surrogate, was modified for antiviral textiles testing. The samples of textiles with antiviral finishing were tested by the bacteriophage-based method and excellent antiviral activity was detected for all tested materials. The woven cotton was used as reference untreated material, the different textile cotton structures with similar square weight were compared and no statistically significant difference was found between the resulting antiviral efficacy values. A simple and quickly feasible screening method for determining the antiviral properties of textiles, especially with leaching-type of treatment, was also designed and tested.

First-principles study of solvent polarity effects in the Menshutkin reaction

Quaternary ammonium salts (QASs) have been used as antimicrobial agents, surfactants, and ionic liquids in electrical double-layer capacitors, rechargeable lithium-ion batteries, and dye-sensitized solar cells. It is well known that solvents and reactants strongly affect the Menshutkin reaction. However, QASs are potentially harmful to humans and the environment. To address these issues, we report the effects of solvent polarity on the thermochemistry of two selected Menshutkin reactions, (1) trimethylamine and 1-iodopropane yielded propyltrimethylammonium, and (2) methylacetamide and 1-iodopropane yielded acetylpropylmethylammonium. We systematically constructed possible QAS unique conformers within the first-principles framework in solvents that have three various polarities: toluene, acetonitrile, and water. The polar solvent shifted both reactions toward exergonic and decreased the Gibbs free activation energy. In addition, the polar solvent changed the favorable reaction for the acetylpropylmethylammonium formation only due to an intramolecular hydrogen bond. Therefore, we suggest that selecting high solvent polarity should be considered to address the potential health and environmental effect.

Identification of a novel 10-hydroxyevodiamine prodrug as a potent topoisomerase inhibitor with improved aqueous solubility for treatment of hepatocellular carcinoma

Natural product evodiamine (Evo) and its synthetic derivatives represent an attractive dual Topo 1/2 inhibitors with broad-spectrum antitumor efficacy. However, the clinical applications of these compounds have been impeded by their poor aqueous solubility. Herein, a series of water-soluble 10-substituted-N(14)-phenylevodiamine derivatives were designed and synthesized. The most potent compound 45 featuring a quaternary ammonium salt fragment achieved robust aqueous solubility and nanomolar potency against a panel of human hepatoma cell lines Huh7, HepG2, SK-Hep-1, SMMC-7721, and SMMC-7721/DOX (doxorubicin-resistant cell). Further studies revealed that 45 could inhibit Topo 1 and Topo 2, induce apoptosis, arrest the cell cycle at the G2/M stage and inhibit the migration and invasion. Compound 45 exhibited potent antitumor activity (TGI = 51.1 %, 10 mg/kg) in the Huh7 xenograft model with acceptable safety profile. In addition, a 21-day long-term dose toxicity study confirmed that the maximum tolerated dose of compound 45 was 20 mg/kg. Overall, this study presented a promising Evo-derived candidate for the treatment of hepatocellular carcinoma.

Entropy-Driven Reversible Melting and Recrystallization of Layered Hybrid Perovskites.

Typical layered 2D A2PbX4 (A: organic ammonium cation, X: Br, I) perovskites undergo irreversible decomposition at high temperatures. Can they be designed to melt at lower temperatures without decomposition? Which thermodynamic parameter drive the melting of layered perovskites? These questions are addressed by considering the melt of A2PbX4 as a mixture of ions (like ionic liquids), and hypothesized that the increase in the structural entropy of fusion (ΔSfus) will be the driving force to decrease their melting temperature. Then to increase structural ΔSfus, A-site cations are designed that are rigid in the solid crystal, and become flexible in the molten state. Different tail groups in the A-site cations form hydrogen-, halogen- and even covalent bonding-interactions, making the cation-layer rigid in the solid form. Additionally, the rotation of ─NH3 + head group is suppressed by replacing ─H with ─CH3, further enhancing the rigidity. Six A2PbX4 crystals with high ΔSfus and low melting temperatures are prepared using this approach. For example, [I-(CH2)3-NH2(CH3)]2PbI4 reversibly melts at 388 K (decomposition temperature 500 K), and then recrystallizes back upon cooling. Consequently, melt-pressed films are grown demonstrating the solvent- and vacuum-free perovskite films for future optoelectronic devices.

Ammonium ion removal from contaminated water using Cikancra natural zeolite

Abstract Water quality in water bodies is deteriorating due to human activities such as industries, agriculture, and households. These activities have been reported to increase the levels of nitrogen species in water bodies, including ammonium (NH4 +). Various processes have been used to reduce NH4 + concentration in water, including adsorption and ion exchange using zeolite which is renowned as an excellent adsorbent and ion exchange material. In this study, we assessed the ability of Cikancra natural zeolite to reduce the NH4 + concentration in water. Heat pre-treatment was carried out on the zeolite to reveal its effect on the NH4 + removal rate. Furthermore, several factors such as contact time, grain size, and initial NH4 + concentration were evaluated to determine the optimum absorption condition. The experimental results reveal that heat-pretreated natural zeolite can reduce the NH4 + concentration by up to 84% after 60 minutes of contact time. Furthermore, the absorption capacity of the zeolite is reaching 2.37 mg/g at an initial NH4 + concentration of 50 mg/L. The evaluation using Freundlich and Langmuir isotherm models indicates that the process occurs physically due to Van Der Waals interaction between the adsorbate and the adsorbent.

Engineering fully quaternized (Dimethylamino)ethyl methacrylate-based photoresins for 3D printing of biodegradable antimicrobial polymers

Nowadays, medical devices or implants are widely used in the medical field to treat different diseases. However, bacterial infections are one of the significant problems associated with medical devices and are recognized as a concern in healthcare worldwide. Addressing this problem has driven the exploration of new materials with potent antibacterial properties. In this regard, quaternary ammonium compounds (QACs), which are organic salts with an alkane chain and a charged part of quaternary ammonium groups, came up with a potent antibacterial activity. Herein, we report for the first-time dimethylamino ethyl methacrylate (DMAEM) derived quaternary ammonium monomer and crosslinker to prepare photoresins for DLP (Digital light processing) 3D printing. The structure of the synthesized monomer and crosslinker was confirmed via FTIR (Fourrier Transform Infrared) and 1H NMR (Hydrogen Nuclear Magnetic Resonance) while the physicochemical properties of the 3D printed polymer were investigated using TGA (Thermogravimetric Analysis), DSC (Differential Scanning Calorimeter) and UTM (Universal testing machine). By optimizing the printing conditions and monomer to crosslinker ratio, we can print high-resolution 3D-printed objects. Additionally, in vitro biodegradation, cytocompatibility, and hemocompatibility tests revealed that the printed polymers are biodegradable, cytocompatible, and hemocompatible in nature. More importantly, the printed polymers exhibited strong antibacterial activity against both gram-negative and gram-positive bacteria, suggesting their potential utility in personalized antibacterial medical devices.

A system with efficient flame retardant and antibacterial properties for the development of exceptional durable functional cotton fabrics

Phosphorus-based flame retardants are widely employed in the study of flame retardancy for cotton fabrics due to their halogen-free nature and high efficiency. The addition of nitrogen and other elements can further enhance flame retardant properties through synergistic effects. However, the synthesis of flame-retardant multifunctional additives based on phosphoramidic ammonium salts has been scarcely reported. In this study, a halogen-free and formaldehyde-free phosphoramidite ammonium salt was synthesized as a synergistic flame retardant multifunctional additive. This compound, with phosphorus as the primary flame retardant element and a nitrogen-containing guanidine group, was used to modify cotton fabrics. The treated fabrics exhibited enhanced flame retardant and antibacterial properties. Notably, cotton fabrics treated with a 17.9 % weight gain showed a damaged length of 4 cm in the vertical flame test, and the LOI value increased to 41.5 %, remaining at 27.3 % even after 50 washing cycles. The results of the cone calorimeter test (CCT) revealed that the peak heat release rate (PHRR) and total heat release (THR) of treated cotton were 30.35 kW/m2 and 5.46 MJ/m2, respectively, representing reductions of 87.04 % and 36.07 % compared to untreated cotton. Physical performance tests indicated only a slight decrease in the strength and whiteness of the cotton fabrics, while softness increased after treatment. Moreover, the treated cotton fabric exhibited excellent antibacterial properties, with antibacterial rates of 99.26 % against E. coli and 98.54 % against S. aureus.

Enhanced pH-sensitive anthocyanin film based on chitosan quaternary ammonium salt: A promising colorimetric indicator for visual pork freshness monitoring

An intelligent pH response indicator film is an easy-to-use device for the real-time monitoring of meat freshness during transport and storage. Therefore, a novel pH-sensitive anthocyanin indicator film composed of polyvinyl alcohol–blueberry anthocyanin (BA)–2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) called PAH-2.0 with 1.2 mg/mL HACC to monitor meat freshness using HACC as the colorimetric enhancer has been developed. BA and HACC were mixed and immobilized in the polyvinyl alcohol matrix by hydrogen bonds, as confirmed via Fourier-transform infrared spectroscopy and X-ray diffraction. The inclusion of HACC improved the color stability and antioxidant and antibacterial properties of the PAH-2.0 film. When applied to pork for freshness monitoring at 4 °C, three freshness stages, including fresh, sub-fresh, and spoiled, could be clearly distinguished based on the color variations of the PAH-2.0 film. The distinct hierarchical color change from purple to blue-violet and finally to grayish-blue was highly correlated with the indicators of pork freshness: pH values, total volatile basic nitrogen, and total viable count. This study provides a simple and promising approach for fabricating meat freshness indicator films with high color recognition accuracy, thereby offering new possibilities for visual meat freshness monitoring.

МИКРОВОДОРОСЛИ ХЛОРЕЛЛА ДЛЯ ОЧИСТКИ СТОКОВ В СЕЛЬСКОМ ХОЗЯЙСТВЕ

A promising way to solve current problems of energy saving and reducing environmental pollution may be the use of microalgae. These simple microorganisms are capable of purifying contaminated wastewater in agriculture. Wastewater contains nitrogen, phosphorus, sulfate and other contaminants. In order to optimize the technology of obtaining biodiesel fuel from lipid components in the conditions of small agricultural producers, the possibility of using Chlorella vulgaris in cleaning from ammonium ions and phosphate ions was studied. Chlorella was cultivated in a photobioreactor on a standard Tamiya medium and wastewater for 10 days at a temperature of 30 ° C and an illumination of 14 kLx in the red (620-740 nm), blue (430-500 nm) and green (500-565 nm) wavelength ranges. The filtrate of the microalgae suspension was collected over several days and assessed for the content of phosphate and nitrate ions using a photometric method. The greatest increase was observed with illumination in the red range (2 times higher), the minimum value in the green. The studies found that cell growth occurs both in synthetic, standard nutrient media and in wastewater, the latter being more costeffective. It was found that when adding chlorella to wastewater, the maximum decrease in the content of ammonium ions and phosphate anions is observed on the 6-7th day (by 19-59% and 5-29%, respectively), which is most likely due to the use of these elements by microalgae for nutrition and maintenance of life. A scheme for growing Chlorella vulgaris on wastewater for further production of lipid components of biodiesel fuel is proposed.

Preinserted Ammonium in MnO2 to Enhance Charge Storage in Dimethyl Sulfoxide Based Zinc-Ion Batteries.

Nonaqueous zinc-ion batteries (NZIBs) featuring manganese dioxide (MnO2) cathodes position themselves as viable options for large-scale energy storage systems. Herein, we demonstrate the use of ammonium cation as a preintercalant to improve the performance of the δ-MnO2 cathode in wet dimethyl sulfoxide based electrolytes. Employing in situ X-ray absorption spectroscopy, Raman spectroscopy, and synchrotron X-ray diffraction, we reveal that the integration of ammonium cations promotes the formation of NH-O-Mn networks. These networks are crucial for manipulating the distortion of the MnO6 octahedral units during discharging, thereby mitigating charge disproportionation, which is a primary limitation to MnO2's charge-storage efficiency. The modified MnO2, through this idea, displays a notable improvement in capacity (∼247 mAh/g) and can pass charge-discharge cycles up to 500 cycles with a capacity retention of 85%. These findings underscore the potential of modified MnO2 in advancing MnO2-based hosts for Zn-MnO2 batteries, marking significant progress toward next-generation energy storage solutions.

Polar Interactions between Substrate and Flavin Control Iodotyrosine Deiodinase Function.

Flavin cofactors offer a wide range of chemical mechanisms to support a great diversity in catalytic function. As a corollary, such diversity necessitates careful control within each flavoprotein to limit its function to an appropriate subset of possible reactions and substrates. This task falls to the protein environment surrounding the flavin in most enzymes. For iodotyrosine deiodinase that catalyzes a reductive dehalogenation of halotyrosines, substrates can dictate the chemistry available to the flavin. Their ability to stabilize the necessary one-electron reduced semiquinone form of flavin strictly depends on a direct coordination between the flavin and α-ammonium and carboxylate groups of its substrates. While perturbations to the carboxylate group do not significantly affect binding to the resting oxidized form of the deiodinase, dehalogenation (kcat/Km) is suppressed by over 2000-fold. Lack of the α-ammonium group abolishes detectable binding and dehalogenation. Substitution of the ammonium group with a hydroxyl group does not restore measurable binding but does support dehalogenation with an efficiency greater than those of the carboxylate derivatives. Consistent with these observations, the flavin semiquinone does not accumulate during redox titration in the presence of inert substrate analogues lacking either the α-ammonium or carboxylate groups. As a complement, a nitroreductase activity based on hydride transfer is revealed for the appropriate substrates with perturbations to their zwitterion.

Enhancing frost-resistant and electrically conductive properties of bacterial cellulose-based IPN hydrogel wound dressings via photopolymerization: Towards epidermal sensor applications

Conventional wound dressings are limited in their application due to the difficulty of maintaining normal use in cold conditions and a lack of functionality. In this study, photopolymerization was employed to fabricate a wound dressing with the capacity to monitor vital signs in cold environments. Utilizing bacterial cellulose (BC) to form an Interpenetrating Network (IPN) structure, the dressing exhibits enhanced water retention and mechanical properties, with a notable increase in mechanical strength to 540.37 KPa. Moreover, it maintains excellent mechanical resilience and electrical conductivity (9.01 × 10−3 S/cm) even at temperatures as low as −20 ℃. Incorporation of positively charged quaternary ammonium salts imparts potent antibacterial properties to the hydrogel against Staphylococcus aureus and Escherichia coli by electrostatically adsorbing to and disrupting negatively charged bacterial cell membranes, resulting in the leakage of internal fluids. The efficacy of the hydrogel in promoting wound healing was validated through rat-infected wound models. Hematoxylin and eosin (H&E) staining confirmed a reduction in inflammation at the wound site, improved wound healing, and a marked increase in the wound healing rate. Moreover, the hydrogel has remarkable electrical conductivity (1.25 × 10−2 S/cm), enabling the detection of subtle signals (e.g., strain 0.25 %) crucial for emergency wound management to prevent infections. Of significant importance, these hydrogels can function as electrodes for monitoring electrocardiogram (ECG) signals and respiratory status, facilitating timely assessment of vital signs in casualties. This innovative hydrogel wound dressing holds promise for simultaneously monitoring human vital signs and treating wounds in cold outdoor settings, thus offering broad applications in the realms of wound management and dressing for cold outdoor sports.

Optimization of Metal-Support Cooperation for Boosting the Performance of Supported Gold Catalysts for the Borylation of C-O and C-N Bonds.

The cooperation of multiple catalytic components is a powerful tool for intermolecular bond formation, specifically, cross-coupling reactions. Supported metal catalysts have interfacial sites between metal nanoparticles and their supports where multiple catalytic elements can work in cooperation to efficiently promote intermolecular reactions. Hence, the establishment of novel guidelines for designing active interfacial sites of supported metal catalysts is indispensable for heterogeneous catalysts which enable efficient cross-coupling reactions. In this article, we performed kinetic and theoretical studies to elucidate the effect of metal-support cooperation for the borylation of C-O bonds by supported gold catalysts and revealed that the Lewis acid density of the supports determined the number of active sites at which metal nanoparticles (NPs) and Lewis acid at the surface of the supports work in cooperation. Furthermore, DFT calculations revealed that strong adsorption of diborons at the interface between Au NPs and supports and a decrease in the LUMO level of adsorbed diboron were responsible for efficient C-O bond borylation. Supported Au catalysts with the optimized metal-metal oxide cooperation sites, namely, Au/α-Fe2O3 catalyst, showed excellent activity for C-O bond borylation, and also enabled the synthesis of organoboron compounds by using continuous-flow reactions. Furthermore, Au/α-Fe2O3 showed high activity for direct C-N bond borylation without the transformation of amino groups to ammonium cations. The results described herein suggest that the optimization of metal-metal oxide cooperation is beneficial for taking full advantage of the potential performance of supported metal catalysts for intermolecular reactions.

Rational Tuning the Proton Conductivity and Stability of Hydrogen-Bonded Organic Frameworks.

In the development of proton conductors, it is crucial to regulate proton conduction pathways and enhance structural stability. In this study, we designed and constructed three hydrogen-bonded organic frameworks (HOFs), namely, NKM-HOF-9, NKM-HOF-10, and NKM-HOF-11, with different dimensional hydrogen-bonding pathways using 4,4'-sulfonyldibenzoic acid and various bases. They are cost-effective and easy to synthesize, allowing for their large-scale production at room temperature. By purposefully altering the ammonium ions, we achieved enhancements in the conductivity and stability of these HOFs. Proton conductivity studies at different humidities and temperatures revealed that at 85 °C and 98% relative humidity, the proton conductivity of NKM-HOF-10 reached 1.7 × 10-3 S cm-1, surpassing that of NKM-HOF-9 by 1 order of magnitude. This improvement was accomplished by increasing the number of proton donors from the base, which resulted in a transition of the hydrogen bond network from discontinuous to continuous, thereby enhancing the proton conduction performance. Moreover, stability tests showed that raising the base's pKa could improve the stability of these frameworks. NKM-HOF-11, which features the highest pKa, demonstrated superior stability by maintaining its structural integrity even at 450 °C.

Magnetic biochar conjugated quaternary ammonium salt-constructed hemoperfusion adsorbent for viral removal with rapid and high-performance

Due to variations in virus structures and their high variability, treating viral infections remains challenging. Moreover, developing vaccines and medications for newly emerged viruses demands a significant time investment. Efficient methods are required to prevent dangerous infections caused by unknown pathogens. Hemoperfusion, with its low cost, can effectively remove toxins from the blood quickly, thus achieving therapeutic effects. The core of the hemoperfusion technology lies in the adsorbent. Therefore, the development of a viral adsorbent aiming to combat viruses through hemoperfusion was envisioned, following general principles to effectively save lives and buy time for the research and development of vaccines and medications. Towards this goal, a facile, green, and low-priced magnetic biochar/quaternary ammonium salt (Fe3O4/C-2) was constructed using the hydrothermal carbonization (HTC) method. HIV lentiviruses were used as a model pathogen to quantify the adsorption capacity and elucidate the adsorption mechanism. Benefiting from a macroporous structure and electrostatic interactions, fabricated Fe3O4/C-2 has a high adsorption capacity (965 ng g−1) and strong suppression of infectious activity (99.99%). Moreover, a low hemolysis ratio (<2%), high cell viability (>100%), high activated partial thromboplastin time (APTT) (67.29 s), and low protein adsorption (<5%) indicate outstanding biocompatibility and good anticoagulant activity. Therefore, Fe3O4/C-2 is expected to serve as a simple and efficient pathogen sorbent for viral diseases treatment.

Air-Stable Boranes and Borinanes Encapsulated in Organogels for Anionic Ring-Opening (Co)Polymerization.

Organoborane reagents play a pivotal role as Lewis acids in acid-base pairs used in anionic polymerization and in other reactions; yet their high sensitivity to oxygen and moisture necessitates effective stabilization to prevent their oxidation and thus maintain their catalytic activity. In this study, we present novel encapsulation methods employing a cost-effective hexatriacontane (C36H74, C36) organogel to stabilize sensitive organoborane reagents, including triethyl borane (TEB) and a borinane-based ammonium salt (B3NBr). These organoboranes encapsulated in stable, self-standing organogel blocks enable their safe handling in open laboratory environments without the need for a glovebox. Upon heating such borane-containing organogel blocks organoboranes could be freed from the organogel and used to mediate both the homopolymerization of propylene oxide (PO) and the copolymerization of PO with CO2. Furthermore, efficient recovery of the C36 gelator from polymerization mixtures is achieved, with mass recovery ranging from 70 % to 90 %. This encapsulation method offers a practical and efficient solution for stabilizing, storing, and handling highly reactive organoborane reagents, thereby broadening their applicability and utilization in various chemical transformations.

Biphasic Production of 5-hydroxymethylfurfural (HMF) in a Recyclable Deep Eutectic Solvent-based System Catalyzed by H4SiW12O40.

The reaction with in situ extraction to yield 5-hydroxymethylfurfural (HMF) from Fru was investigated using a biphasic system based on a self-consuming deep eutectic solvent (DES) as reaction phase. The significance of choline chloride (ChCl), a cost-effective and safe quaternary ammonium salt, was evident in enhancing 5-HMF yield through fructose dehydration and concurrently suppressing side reactions. The DES system demonstrated fast reactions with high selecivities and recyclability across five cycles. The observed decline in H4SiW12O40 activity, primarily due to proton leaching, was successfully restored with the addition of HCl. Furthermore, ChCl exhibited ease of recrystallization in the presence of acetonitrile. This research proposes an environmentally friendly approach for 5-HMF production through a reusable-biphasic process. The presented reaction system suppresses completely the formation of levulinic and formic acid leading to HMF yields of up to 84% of selectivities of up to 88% after 30 minutes at 80 °C. The system was recycled over 16 runs and after an initial slight loss of activity the system in the run 0-5, run 6-15 has shown a constant HMF output as in the first recycling run.

Atmospheric NH3 in urban Beijing: long-term variations and implications for secondary inorganic aerosol control

Abstract. Ammonia (NH3) has major effects on the environment and climate. In situ measurements of NH3 concentrations taken between June 2009 and July 2020 at an urban site in Beijing were analyzed to study its long-term behavior, responses to meteorological conditions, and influences on the formation of secondary inorganic aerosols (SIAs). The 11-year average NH3 mixing ratio was 26.9±19.3 ppb (median 23.5 ppb). The annual average NH3 mixing ratio increased from 2009 to 2017 by 50 % and then decreased by 49 % from 2017 to 2020. Notably, the long-term trend for NH3 at the ground level did not align with the trends derived from satellite observations and emission estimates. The NH3 concentration exhibited a stronger correlation with the daily variation in water vapor (H2O) concentration than with air temperature. Thermodynamic modeling revealed the nonlinear response of SIAs to NH3, with increased sensitivity when its concentration was reduced to 40 % of the initial level. Although reducing NH3 concentrations can improve air quality during winter, controlling acid gas concentrations has a greater effect than controlling NH3 concentrations on reducing SIA concentrations, until NH3 and acidic gas concentrations are reduced below 80 % of their current levels. Nevertheless, the increased mass proportion of ammonium salts in SIAs during the observation period indicates that future control measures for NH3 concentrations may need to be prioritized in Beijing.

Fabrication of Cross‐Linked Polyimide Hollow Microspheres With Lightweight, Thermal Resistance and Controllable Size

AbstractPolyimide (PI) hollow microspheres possess lightweight and excellent thermal resistance, which are widely used in microreactors, catalysis, adsorption separation, high‐temperature insulation, and so on. In this manuscript, PI hollow microspheres are fabricated by constructing a crosslinked structure combined with gradient heating. The formation of PI hollow microspheres includes gas nucleation, expansion, and imidization. The PI hollow microspheres size is controlled by adjusting polyester ammonium salts size, and microspheres size is distributed in 309–956 µm. PI hollow microspheres have lightweight, excellent heat resistance and carbonization performance, bulk density, initial decomposition temperature, and weight residue at 800 °C is 87.3–178.6 kg m−3, 533.6 °C and 59.8%. The PI hollow microspheres have potential applications in high‐temperature resistant and multifunctional composite materials preparation. Moreover, this method is simple, efficient, and highly operable, which can be used for large‐scale production of PI hollow microspheres.

Application Properties of Gemini Quaternary Ammonium Salt with Quadra‐cationic Sites and Sodium Fatty Alcohol Polyoxyethylene Ether Carboxylate Mixed Systems

AbstractThe application properties such as foam property, electrolyte tolerance, antibacterial activity and antistatic performance of the mixed systems of a novel Gemini quaternary ammonium salt with quadra‐cationic sites (TC‐GS) and sodium fatty alcohol polyoxyethylene ether carboxylate (AE9CNa) at various molar fraction of TC‐GS (αTC‐GS), were investigated systematically. Results show that TC‐GS/AE9CNa mixed systems with different ratios form a homogeneous and transparent solution, which exhibits excellent foam stability and antibacterial activity. The foam volume of the mixed system remains nearly constant from 400 s to 1000 s, and even when TC‐GS is 10 mg/L in the mixed systems, the antibacterial rates against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) for 2 min. are all exceeded 99 %. The mixed systems of TC‐GS/AE9CNa at various αTC‐GS also demonstrate the superior electrolyte tolerance, their maximum tolerance of NaCl, CaCl2 and MgCl2 is severally beyond 270 g/L, 180 g/L and 180 g/L. In addition, both TC‐GS solution and the mixed systems have good antistatic properties, which can reduce the surface resistance of polyester fabric to ≤1010 Ω.