Synthesis and characterization of quaternized poly(phthalazinone ether sulfone ketone)for anion-exchange membrane

Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone （NMP）, N,N-dimethylacetamide （DMAc） and chloroform. Quaternized poly（phthalazinone ether sulfone ketone） （QAPPESK） was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid （98%） and swollen in N,N-dimethylformamide （DMF）. The vanadium redox flow battery （V-RFB） using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.

Cytocompatibility with osteogenic cells and enhanced in vivo anti-infection potential of quaternized chitosan-loaded titania nanotubes

Infection is one of the major causes of failure of orthopedic implants. Our previous study demonstrated that nanotube modification of the implant surface, together with nanotubes loaded with quaternized chitosan （hydroxypropyltrimethyl ammonium chloride chitosan, HACC）, could effectively inhibit bacterial adherence and biofilm formation in vitro. Therefore, the aim of this study was to further investigate the in vitro cytocompatibility with osteogenic cells and the in vivo anti-infection activity of titanium implants with HACC-loaded nanotubes （NT-H）. The titanium implant （Ti）, nanotubes without polymer loading （NT）, and nanotubes loaded with chitosan （NT-C） were fabricated and served as controls. Firstly, we evaluated the cytocompatibility of these specimens with human bone marrow-derived mesenchymal stem cells in vitro. The observation of cell attachment, proliferation, spreading, and viability in vitro showed that NT-H has improved osteogenic activity compared with Ti and NT-C. A prophylaxis rat model with implantation in the femoral medullary cavity and inoculation with methiciUin-resistant Staphylococcus aureus was established and evaluated by radiographical, microbiological, and histopathological assessments. Our in vivo study demonstrated that NT-H coatings exhibited significant anti-infection capability compared with the Ti and NT-C groups. In conclusion, HACC-loaded nanotubes fabricated on a titanium substrate show good compatibility with osteogenic cells and enhanced anti-infection ability in vivo, providing a good foundation for clinical application to combat orthopedic implant-associated infections.

Preparation and antibacterial properties of polycaprolactone/quaternized chitosan blends

This article is a preliminary study on antibacterial blends of polycaprolactone,chitosan and quaternized chitosan by melt processing.Blends were characterized,mechanical test and antibacterial evaluation against Escherichia coli and Staphylococcus aureus,were conducted.Results showed that the antibacterial potential of chitosan was limited in blends and polycaprolactone/chitosan did not show significant antibacterial effect compared with neat polycaprolactone(PCL).Inhibition rates of polycaprolactone/quaternized chitosan were 39.2%99.9%against Escherichia coli,while inhibition rate was 40.9%99.9%against Staphylococcus aureus.When quaternized chitosan(QCTS)content was up to 20%,blends exhibited 99.9%inhibition rates against both two types of bacteria.

Electroneutral Quaternization/Sulfosuccination for Alleviating the Adverse Effect of Paste Aging on the Properties of Corn Starch Film

For the purpose of alleviating the adverse effect of paste aging on the properties of corn starch film, a series of electroneutrally quaternized/sulfosuccinylated starches（EQSS） with different degrees of substitution（DS） were synthesized via the quaternization/sulfosuccination of acid-thinned corn starch（ATS） by varying the amounts of N-（3-chloro-2-hydroxypropl） trimethylammonium chloride, maleic anhydride, and sodium hydrogen sulfite. The influence of paste aging on the properties of starch film cast from heat-induced starch paste was investigated and the properties were explored in terms of tensile strength, elongation, work at break, degree of crystallinity, and flex-fatigue resistance. The experimental results showed that the paste ageing generated adverse influence on the elongation, work at break, and flex-fatigue resistance of starch film. Further experiments showed that electroneutral quaternization/sulfosuccination of starch were able to alleviate the negative effect of paste ageing on the elongation, work at break, and flex-fatigue resistance, thereby obviously enhancing the elongation, work at break and flex-fatigue resistance, and thus reducing the drawback of brittleness. The enhancement depended on the amounts of the substituents introduced. With the increase in DS value, the elongation and work at break as well as flex-fatigue resistance continuously rose, whereas the tensile strength gradually reduced.

Homogeneous Synthesis and Characterization of Quaternized Cellulose Derivatives in NaOH-urea Aqueous Solutions

Quaternized cellulose( QC) derivatives were synthesized by reacting cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride( CHPTAC) in an aqueous solution of Na OH-urea. The chemical structures and physical properties of the obtained QC derivatives were characterized using nitrogen content analysis,Fourier transform infrared spectroscopy( FT-IR),~1H-nuclear magnetic resonance(1H-NMR),X-ray diffraction( XRD),and thermal gravity analysis( TGA). The FT-IR and ~1H-NMR results confirmed the successful introduction of cationic quaternary ammonium groups into the main chain of cellulose. A series of QC derivatives with the degree of substitution( DS) values ranging from 0. 33 to 0. 80 were derived by adjusting the molar ratio of CHPTAC to anhydroglucose unit( AGU) of cellulose,concentration of cellulose in the Na OH-urea solution,as well as reaction temperature and time. According to the DS values of the QC derivatives,the optimized synthetic conditions were as follows: 25℃ reaction temperature,3% cellulose in Na OH-urea solution,the molar ratio of etherification agent to glycosidic cellulose of 15∶ 1,and 12 h reaction time. The TGA and XRD results revealed that the crystalline structure was destroyed during etherification,and the thermal stability of the QC derivatives was lower than that of cellulose.

Immunostimulatory eff ect of quaternary degree and acetyl group of quaternized chitosan on macrophages RAW 264.7

Hydroxypropyltrimethyl ammonium chloride chitosan(HACC)and hydroxypropyltrimethyl ammonium chloride fully deacetylated chitosan(De-HACC)were synthesized with various degrees of substitution by altering the ratio of chitosan to glycidyl trimethyl-ammonium chloride(GTMAC).The effects of the quaternary ammonium degree and the acetyl group of these polymers on immunostimulatory activities were detected in RAW 264.7 cells.The expression levels of nitrogen oxide(NO),interleukin-6(IL-6)and tumor necrosis factor(TNF-α)were compared.Results show that the removal of acetyl groups in chitosan obviously improved the degree of substitution of quaternary ammonium salts.In addition,HACC and De-HACC were capable of promoting immunological activity in a substitution-dependent manner;HACC was positively correlated,and De-HACC was negatively correlated.Among tested ratios,HACC-30%and De-HACC-54%performed better than the others,and De-HACC-54%performed the best.Generally,quaternized chitosan possesses immunostimulatory activity,which is related to the degree of quaternization and the acetyl group.

Quaternized polymer binder for lithium-sulfur batteries:The effect of cation structure on battery performance

Lithium–sulfur (Li–S) batteries are great candidates for energy storage systems, but need to overcome theissues of low sulfur utilization and polysulfide shuttling for use in large-scale commercial applications.Recently, quaternized polymers have received much attention for their polysulfide trapping propertiesdue to electrostatic interaction. In this work, we report a series of polyarylether sulfone (PSF) binderswith different cation structures including imidazolium (Im), triethylammonium (Tr), and morpholinium(Mo). The ability of the these quaternized binders and the conventional poly(vinylidene fluoride) or PVDFbinder to capture polysulfide increases in the order of PVDF << PSF-Mo < PSF-Tr< PSF-Im. The delocalizedcharge on the imidazolium cation may promote the interaction between PSF-Im and polysulfide asindicated by an X-ray photoelectron spectroscopic study. The PSF-Im based cathodes showed the highestcapacity retention (77% at 0.2 C after 100 cycles and 84% at 0.5 C after 120 cycles), and the bestrate capability. This work demonstrates the importance of the cation structure in the design of efficientquaternized binders for high performance Li–S batteries.

The Adsorption Effect of Quaternized Chitosan Derivatives on Bile Acid

Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quatemized chitosan derivatives are favorable adsorbents for bile acid.

Synthesis of Chitosan Quaternary Ammonium Salts

A series of N-alkyl or N-aryl chitosan quaternary ammonium salts were prepared via Schiffs base intermediates. Quaternization of N-substituted chitosan derivatives was carried out using methyl iodide to produce water-soluble cationic chitosan quaternary ammonium salt. The products were characterized by IR, (HNMR)-H-1 and elemental analysis. The degree of substitution of chitosan quaternary ammonium salt was calculated by elemental analysis.

Synthesis and Characterization of Some New Cationic Derivatives of Biological Interest

A homologous series of cationic surfactants were synthesized and characterized by spectral studies, mass, IR, 1H NMR, 13C NMR, 2D NMR and elemental analysis. The surface activities of these amphiphiles were measured, including surface tension (γ), critical micelle concentration (CMC), effectiveness (pcmc), efficiency (PC20), maximum surface excess (Γmax) and minimum surface area (Amin) at 25℃. Adsorption and micellization free energies of these amphiphiles in their solutions showed a good tendency towards adsorption at the interfaces. The synthesized amphiphiles showed good antimicrobial activity.

Surface Properties and Compatibility with Blood of New Quaternized Polysulfones

The paper describes some properties of new quaternized polysulfones obtained by quaternization of chloromethylated polysulfone with different tertiary amines - N,N-dimethylethylamine and N,N-dimethyloctylamine. Hydrophilic/hydrophobic properties, morphological aspects and compatibility with red blood cells and platelets are affected by the alkyl radicals and by history of the formed films. The results obtained are useful in biomedical applications, including evaluation of bacterial adhesion to the surfaces, or utilization of modified polysulfones as semipermeable membranes.

Nuclear-Chemical Synthesis of 1,4-Diazine Quaternary Salts

Ion-molecular reactions of nucleogenic phenyl cations with the nucleophilic centers of 1,4-diazines have been investigated for the first time. Previously unknown tritium labeled N-phenyl quaternary derivatives of pyrazine and quinoxaline, which are potential radioactive biomarkers, have been obtained by nuclear-chemical method.

A dural substitute based on oxidized quaternized guar gum/porcine peritoneal acellular matrix with improved stability, antibacterial and anti-adhesive properties

Trauma and neurosurgery often result in dural defects and are followed by serious complications or even death, finding suitable dural replacement materials to repair the defective dura has important clinical significance. Porcine peritoneal acellular matrix(PPAM) is a promising alternative material, but its poor stability makes it difficult to meet the various needs of dural reconstruction. In this work, we developed a novel antibacterial cross-linking agent oxidized quaternized guar gum(OQGG) and used it for the first time to stabilize PPAM to construct a dural mater substitute(OQGG-PPAM). The results showed that 1.5%OQGG-PPAM presented suitable mechanical property as well as good thermal stability and resistance to enzymatic degradation. It also exhibited good antibacterial activity and good anti-leakage ability. Furthermore, 1.5% OQGG-PPAM not only exhibited excellent cell compatibility but also significantly stimulated the secretion of b FGF and VEGF from seeded cells which was convenient for dural remodeling. In vivo experiment, it also exhibited the excellent histocompatibility and good anti-adhesion property. This study showed that OQGG can be used as a novel antibacterial cross-linking reagent for crosslinking natural tissues and 1.5% OQGG-PPAM was a potential candidate material for dura mater substitute.

Enhanced phosphate removal using zirconium hydroxide encapsulated in quaternized cellulose

Zirconium-based materials are efficient adsorbent for aqueous phosphate removal.However,current zirconium-based materials still show unsatisfied performance on adsorption capacity and selectivity.Here,we demonstrate a zirconium hydroxide encapsulated in quaternized cellulose(QC-Zr) for the selective phosphate removal.Zirconium hydroxide nanoparticles were simultaneously generated in situ with the QC framework and firmly anchored in the three-dimensional(3D) cross-linked cellulose chains.The maximum P adsorption capacity of QC-Zr was 83.6 mg P/g.Furthermore,the QC-Zr shows high P adsorption performance in a wide pH range,generally due to the electrostatic effects of quaternized cellulose.The enhanced adsorption of P was also achieved in the presence of competing anions(including Cl^-,NO3^-,SO4^2-,SO4^4-) and humic acid(HA) even at a molar ratio up to 20 levels.The column adsorption capacity of QC-Zr reached 4000 bed volumes(BV) at EBCT=0.5 min as the P concentration decreased from 2.5 to 0.5 mg/L.Mechanism study revealed that both-N^+(CH3)3 groups and zirconium hydroxide were involved in phosphate adsorption via electrostatic interactions between -N^+(CH3)3 and phosphate,and the formation of zirconium hydrogen phosphate(Zr(HPO4)x).The 31 P nuclear magnetic resonance(NMR) study implied that P surface-precipitated and inner-sphere complexed with zirconium hydroxide at a ratio of 3:1.

De novo strategy with engineering a multifunctional bacterial cellulose-based dressing for rapid healing of infected wounds

The treatment and healing of infected skin lesions is one of the major challenges in surgery.To solve this problem,collagen I(Col-I)and the antibacterial agent hydroxypropyltrimethyl ammonium chloride chitosan(HACC)were composited into the bacterial cellulose(BC)three-dimensional network structure by a novel membrane-liquid interface(MLI)culture,and a Col-I/HACC/BC(CHBC)multifunctional dressing was designed.The water absorption rate and water vapor transmission rate of the obtained CHBC dressing were 35.78±2.45 g/g and 3084±56 g m^(-2)⋅day^(-1),respectively.The water retention of the CHBC dressing was significantly improved compared with the BC caused by the introduced Col-I and HACC.In vitro results indicated that the combined advantages of HACC and Col-I confer on CHBC dressings not only have outstanding antibacterial properties against Staphylococcus aureus(S.aureus)compared with BC and CBC,but also exhibit better cytocompatibility than BC and HBC to promote the proliferation and spread of NIH3T3 cells and HUVECs.Most importantly,the results of in vivo animal tests demonstrated that the CHBC dressings fully promoted wound healing for 8 days and exhibited shorter healing times,especially in the case of wound infection.Excellent skin regeneration effects and higher expression levels of collagen during infection were also shown in the CHBC group.We believe that CHBC composites with favorable multifunctionality have potential applications as wound dressings to treat infected wounds.

Antibacterial Behaviour of Quaternized Poly(vinyl chloride)-g-Poly(4-vinyl pyridine) Graft Copolymers

Amphiphilic graft copolymers consisting of poly（vinyl chloride）（PVC） main chains and poly（4-vinyl pyridine）（P4VP） side chains were synthesized via atom transfer radical polymerization（ATRP） using direct initiation of chlorine atoms. The successful synthesis of PVC-g-P4 VP graft copolymers was confirmed by Fourier transform infrared spectroscopy（FTIR） and proton nuclear magnetic resonance（1H-NMR）. Transmission electron microscope（TEM） and small angle X-ray scattering（SAXS） analysis showed that PVC-g-P4 VP exhibited microphase-separated, ordered structure with 37.6 nm of domain spacing, which was not observed in neat PVC. For antibacterial applications, the tertiary nitrogen atoms of PVC-gP4 VP was quaternized using 1-bromohexane, as confirmed by FTIR measurements. Bacteria including Escherichia coli（E. coli）, Staphylococcus aureus（S. aureus）, Bacillus cereus（B. cereus）, and Pseudomonas aeruginosa（P. aeruginosa） were completely killed in 24 h on the quaternized PVC-g-P4VP（46% grafting） surface, indicating its excellent antibacterial behavior while it showed to be cytotoxic to mammalian cell.

Comparison of Hair Fatty Alcohols by N-Alkylpyridinium Isotope Quaternization and Matrix-assisted Laser Desorptionl ionization Mass Spectrometry for Drug Abuse Monitoring

Based on our previous report on N-alkylpyridinium isotope quaternization （NAPIQ） for the analysis of alcoholic and α,β-unsaturated ketone compounds, we have further applied NAPIQ method in the screening of hair lipids in drug abusers. Relative isotopic quantification was used for comparison of fatty alcohols between normal and drug abuse group, The NAPIQ strategy was proven to be a high-throughput method in the metabolic comparison studies of different group samples. The attached N-cationic pyridinium significantly improved the detection sensitivity for these fatty alcohols in matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric （MALDI-FTMS） analysis. The experimental results showed that the levels of fatty alcohols in the hair of heroin abuse group decreased significantly compared with the normal groups, which may be the results of the inducing of peroxidation enzyme. NAPIQ was proven to be an effective and alternative method in the research of fatty alcoholic metabolism for drug abuse monitoring.

Quaternized chitosan-assisted in situ synthesized CuS/cellulose nanofibers conductive paper for flexible electrode

Cellulose nanofibers(CNF)are considered to be a potential substrate of energy material for energy storage devices due to the foldable,lightweight,recyclable and environmentally friendly feature.However,the energy materials tend to distribute unevenly or fall off from CNF easily,resulting in the decrease of the devices’overall performance.Here,for the first time,we used quaternized chitosan(QCS)as stabilizer and adhesive to in situ synthesize and deposite copper sulfide nanocrystals(CuS-NCs)on CNF and further obtained the conductive paper for flexible supercapacitors.In the presence of QCS,CuS-NCs deposited in situ on CNF can be capped and stabilized by the QCS molecular chains for uniform distribution,which is conducive to the capacitive behavior and electrochemical stability of composite paper.The result shows that the specific capacitance of the composite paper was as high as 314.3 F/g at a current density of 1 A/g,a high rate capacitance of 252.6 F/g was achieved even at a high current density of 10 A/g.It reveals that the composite paper exhibited better electrochemical performance than many other CuS-based electrode materials for supercapacitor.More importantly,the composite paper performed well in various folding state without changing much electrochemical performance.Therefore,this work provides a novel strategy to in situ fabricate paper-based electrode for nextgeneration flexible energy-storage system.

Biocompatible and antibacterial soy protein isolate/quaternized chitosan composite sponges for acute upper gastrointestinal hemostasis

Innovative biomedical applications have high requirements for biomedical materials.Herein,a series of biocompatible,antibacterial and hemostatic sponges were successfully fabricated for the treatment of acute upper gastrointestinal bleeding(AUGB).Quaternized chitosan(QC)and soy protein isolate(SPI)were chemically cross-linked to obtain porous SPI/QC sponges(named SQS-n,with n¼30,40,50 or 60 corresponding to the weight percentage of the QC content).The chemical composition,physical properties and biological activity of SQS-n were investigated.SQS-n could support the adhesion and proliferation of L929 cells while triggering no obvious blood toxicity.Meanwhile,SQS-n exhibited good broad-spectrum antibacterial activity against both grampositive bacteria(Staphylococcus aureus)and gram-negative bacteria(Escherichia coli).The in vivo hemostatic effect of SQS-n was evaluated using three different bleeding models.The results revealed that SQS-50 performed best in reducing blood loss and hemostatic time.The overall hemostatic effect of SQS-50 was comparable to that of a commercial gelatin sponge.The enhanced antibacterial and hemostatic activities of SQS-n were mainly attributed to the QC component.In conclusion,this work developed a QC-functionalized hemostatic sponge that is highly desirable for innovative biomedical applications,such as AUGB.

Highly conductive and robust composite anion exchange membranes by incorporating quaternized MIL-101(Cr)

With well-defined channels and tunable functionality, metal-organic frameworks （MOFs） have inspired the design of a new class of ion-conductive compounds. In contrast to the extensive studies on proton- conductive MOFs and related membranes attractive for fuel cells, rare reports focus on MOFs in preparation of anion exchange membranes. In this study, chloromethylated MIL-101 （Cr） was prepared and incor- porated into chloromethylated poly （ether ether ketone） （PEEK） as a multifunctional filler to prepare imidazolium PEEK/imidazolium MIL-101（Cr） （ImPEEK/ImMIL-101（Cr）） anion exchange membrane after synchronous quaternization. The successful synthesis and chloromethylation of MIL-101（Cr） were veri- fied by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy while the enhanced performance of composite membranes in hydroxide conductivity, mechanical strength and dimensional stability were evaluated by alternating-current impedance, electronic stretching machine and measurement of swelling ratio. Specifically, incorporating 5.0wt% ImMIL-101（Cr） afforded a 71.4% increase in hydroxide conductivity at 20℃, 100% RH. Besides, the composite membranes exhibited enhanced dimensional stability and mechanical strength due to the rigid framework of ImMIL- 101（Cr）. At room temperature and the ImM1L-101（Cr） content of 10wt%, the swelling ratio of the ImPEEK/lmMIL-101（Cr） was 70.04% lower while the tensile strength was 47.5% higher than that of the pure membrane.