Synthesis and Electrochemical Performance of Spheroid LiNi<Subscript>1/3</Subscript>Co<Subscript>1/3</Subscript>Mn<Subscript>1/3</Subscript>O<Subscript>2</Subscript> in the Electrolyte Modified by Ethylene Sulfate and Methylene Methanedisulfonate

In this study, spheroid LiNi_1/3Co_1/3Mn_1/3O₂ (NCM111) cathode material were synthesized using LiOH with Ni_0.5Co_0.2Mn_0.3(OH)₂ precursor by a simple solid-state reaction, and characterized by X-ray diffraction and scanning electron microscopy. Electrochemical behavior of NCM111 was investigated by electrochemical impedance spectroscopy (EIS) combining with cyclic voltammogram (CV) and charge/discharge test in the 1 M LiPF₆-EC:EMC electrolyte with ethylene sulfate (DTD) and methylene methanedisulfonate (MMDS) additives either singly or in combination with high cutoff voltage of 3.0–4.5 V at room temperature of 25 °C or elevated temperature of 55 °C. It was found that DTD additive can increase the initial coulombic efficiency of NCM111, and the spheroid NCM111 can obtain the maximum initial discharge capacity of 177.81 mAh/g with the 2 wt% DTD, and keep 92.29% capacity retention after 80 cycles. The MMDS additives would decrease the initial discharge capacity of the NCM111, and enhance significantly long cycle life of the NCM111 with the capacity retention of 99.23% over 80 cycles at high voltage of 4.5 V. The additive combination 2 wt% DTD?+?1 wt% MMDS was an optimal additive combination, demonstrating the 102.2% capacity retention over 80 cycles at room temperature and the 94.2% capacity retention over 70 cycles at elevated temperature of 55 °C. EIS results revealed that the additive blend of 2 wt% DTD?+?1 wt% MMDS can drastically lower the kinetics impedance and suppress the growth rate of R _ct for the NCM111 electrode.     

Poly(vinyl alcohol)/CaCO3‐diacid nanocomposite: Investigation of physical and wetting properties and application in heavy metal adsorption

Poly(vinyl alcohol) (PVA) nanocomposite and modified CaCO₃ nanoparticles (NPs) were fabricated by ultrasound agitation method with particle content altering from 3, 5, and 8 wt %. The CaCO₃ surface was successfully treated by 10 wt % of bioactive dicarboxylic acid (DA). The influences of loading modified NPs on the thermal, mechanical, adsorption, contact angle, and physical properties of the poly(vinyl alcohol) nanocomposite films were thoroughly studied. The results showed that incorporation of modified CaCO₃ into the PVA matrix had better performance than the pure PVA. Meanwhile, tensile strength, Young's modulus, and thermal stability are enhanced from 33.36 MPa, 1.26 GPs, and 242.918C (neat PVA) to 81.7 MPa, 4.81 GPa, and 312.95 °C (PVA/CaCO₃‐DA NC 5 wt %), respectively. Also, the adsorption capacity of the PVA/CaCO₃‐DA NCs 5 and 8 wt % revealed that the NC films could act as an appropriate absorbent for the removal of Cd(II) ions with maximum adsorption capacity of about 20.70 and 25.19 mg g^?1 for Cd(II), respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45414.     

Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles coated by new functionalized tetraaza-2,3 dialdehyde micro-crystalline cellulose: synthesis,characterization, and catalytic application for degradation of Acid Yellow 17

In this study, we developed an original approach for preparing cellulose-coated magnetite nanoparticles (NPs). Two novel Schiff bases (PDA-g-DAC) and [Bz-(PDA-g-DAC)] were synthesized via condensation reactions of periodate oxidized micro-crystalline cellulose (DAC) with o-phenylene diamine (PDA) to obtain its azomethine derivative with 85% yield. Subsequently, the functionalization of (PDA-g-DAC) with benzil (Bz) yields the tetraaza macrocycle [Bz-(PDA-g-DAC)]. The physicochemical characterization of the condensation products was performed using ¹³CNMR, FTIR, ATG, DSC, and X-ray diffraction techniques. Magnetic nanomaterial-based Schiff base cellulose was successfully prepared using in situ chemical co-precipitation of coordinated ferric and ferrous ions in cellulose Schiff base matrix under optimized conditions, and then, its magnetic properties were characterized. The results demonstrated that the Fe₃O₄ NPs coated with [Bz-(PDA-g-DAC)] were homogeneously coated in the matrix under ultrasonic irradiation with the saturation magnetization of 69.50 emu g^?1. In addition, XRD line broadening analysis showed that the average particle size of the NPs was 37.3 nm. Furthermore, FTIR spectra demonstrated that [Bz-(PDA-g-DAC)] concavity was anchored to magnetite Fe₃O₄ NPs through azomethine groups. Vibrating sample magnetometry (VSM) of [Bz-(PDA-g-DAC)@Fe₃O₄] magnetic nanocomposite samples showed the typical behavior of ferromagnetism. This study provided a green and facile method to inhibit magnetic nanoparticle aggregation. Activity results revealed that the prepared [Bz-(PDA-g-DAC)@Fe₃O₄] catalyst shows the maximum activity for degradation of Acid Yellow 17 (AY17) compared to other prepared catalysts. After degradation reaction, the [Bz-(PDA-g-DAC)@Fe₃O₄] catalyst was recovered from the reaction mixture via an external magnet and used for further five consecutive cycles with excellent catalytic activity, successively, which was comparable to the fresh catalyst. The catalyst degradation efficiency and its easy separation exhibited that [Bz-(PDA-g-DAC)@Fe₃O₄] catalyst is a promising material for the removal of AY17 from aqueous solutions in green chemistry perspectives.     

Synthesis of polyamine-grafted chitosan and its adsorption behavior

The development of new environment-friendly and efficient adsorbents has attracted a great interest in recent years. In this study, ethylene diamine-grafted chitosan copolymer (CS–MAA–EN) and triethylene tetramine-grafted chitosan copolymer (CS–MAA–TN) were synthesized to remove heavy metal ions from water. The influence of pH, adsorbents dosage and initial metal concentration were investigated to study the adsorbing effect of CS–MAA–EN and CS–MAA–TN for the removal of Cu²⁺ from aqueous solutions. The equilibrium adsorption capacities of CS–MAA–EN and CS–MAA–TN were 85.91 and 102.67 mg/g, respectively. The adsorption process was fitted better by the Langmuir isotherm model (R ² = 0.9993, 0.9991) than the Freundlich isotherm model (R ² = 0.8781, 0.8775). The adsorption kinetics confirmed that the adsorption mechanism could be better described by the pseudo-second-order equation. Two adsorbents showed excellent desorption efficiency (D _e) and reuse ratio (R _u). D _e and R _u of CS–MAA–EN were evaluated as 95.2 and 89.35 %, respectively, and those values of CS–MAA–TN were 92.73 and 83.25 %. The competitive adsorption results of the two adsorbents indicated that the rate sequence was Fe³⁺ > Cu²⁺ > Cr⁶⁺ > Ni²⁺ > Zn²⁺.     

Synthesis,characterization and adsorption of cationic dyes by CS/P(AMPS-<Emphasis Type="Italic">co</Emphasis>-AM) hydrogel initiated by glow-discharge-electrolysis plasma

In this work, a novel chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic amide) (CS/P(AMPS-co-AM)) hydrogel was successfully prepared by a simple one-step method using glow-discharge-electrolysis plasma (GDEP) initiated copolymerization, in which N,N′-methylenebisacrylamide was used as a cross-linking agent. A copolymerization mechanism of AMPS and AM onto CS initiated by GDEP was proposed. The structure, thermal stability and morphology of CS/P(AMPS-co-AM) hydrogel were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), TG/DTG, and scanning electron microscope (SEM). This hydrogel was employed as an absorbent for the removal of methylene blue (MB) and malachite green (MG) from aqueous solutions. The effects of pH, contact time and equilibrium concentration on the dye adsorption were investigated batchwise. FTIR and XRD indicated that AM and AMPS were grafted onto the CS backbone successfully, forming copolymer. TG/DTG suggested that grafted AMPS and AM onto CS could change the thermal stability of the CS. SEM showed a unique three-dimensional porous structure for the CS/P(AMPS-co-AM) hydrogel. The optimum pH for the removal of cationic dyes was 5.8, and time of adsorption equilibrium was achieved in 90 min. The CS/P(AMPS-co-AM) hydrogel exhibited a very high adsorption potential, and its adsorption capacities calculated based on the Langmuir isotherm for MB and MG were 1,538.5 and 917.4 mg g^?1, respectively. The dye adsorption data fitted well to the pseudo-second-order model and Langmuir model at 25 °C with pH 5.8.     

Reusability and selective adsorption of Pb<Superscript>2+</Superscript> on chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-<Emphasis Type="Italic">co</Emphasis>-acrylic acid) hydrogel

Reusability and selective adsorption toward Pb²⁺ with the coexistence of Cd²⁺, Co²⁺, Cu²⁺ and Ni²⁺ ions on chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic acid) [CS/P(AMPS-co-AA)] hydrogel, a multi-functionalized adsorbent containing –NH₂, –OH, –COOH and –SO₃H groups was studied. The CS/P(AMPS-co-AA) was prepared in aqueous solution by a simple one-step procedure using glow discharge electrolysis plasma technique. The reusability of adsorbent in HNO₃, EDTA-2Na and EDTA-4Na was investigated in detail. The competitive adsorption of the metal ions at the initial stage was compared between their equal mass concentration and equal molar concentration. In addition, the adsorption mechanism of the adsorbent for adsorption of Pb²⁺ was also analyzed by XPS. The results showed that the optimum pH of adsorption was 4.8, and time of adsorption equilibrium was about 180 min. Adsorption kinetics fitted well in the pseudo second-order model. The equilibrium adsorption capacities of Pb²⁺, Cd²⁺, Co²⁺, Cu²⁺, and Ni²⁺ at pH 4.8 were obtained as 673.3, 358.3, 176.7, 235.0 and 171.7 mg g^?1, in their given order. The adsorbent displayed an excellent reusability using 0.015 mol L^?1 EDTA-4Na solution as the eluent, and the desorption ratio could not correctly reflect the true characteristics of adsorption/desorption process. Moreover, the adsorbent showed good adsorption selectivity for Pb²⁺. The molar adsorption capacity at the initial stage with equal molar concentration was more reliable than the mass adsorption capacity during the study of selective adsorption. According to the XPS results, the adsorption of Pb²⁺ ions by the CS/P(AMPS-co-AA) absorbent could be attributed to the coordination between N atom and Pb²⁺ and ion-exchange between Na⁺ and Pb²⁺.     

Synthesis and characterization of maleylated cellulose-<Emphasis Type="Italic">g</Emphasis>-polyacrylamide hydrogel using TiO<Subscript>2</Subscript> nanoparticles under sunlight

Graft polymerization onto the cellulose is one way to produce semisynthetic copolymers and semiconductors were hardly used as initiators. Maleylated cellulose (MC) with different degree of carboxyl groups was synthesized and degree of carboxyl groups was determined using titration method. Then the graft copolymers of acrylamide (AM) on MC were synthesized by titanium dioxide semiconductor photoinitiator in aqueous suspension under sunlight. The effect of different parameters, such as the degree of carboxyl groups, degassing of atmosphere, reactor type, light source, MC/AM ratio, and initiator concentration, was evaluated in the synthesis of graft copolymers. MC with a high degree of carboxyl groups about 2.8 mmol g^?1 was selected for graft photopolymerization. Maximum monomer conversion (55%) for Maleylated cellulose-g-polyacrylamide (MC-g-PAM) was achieved with 0.5 mg TiO₂, MC/AM = 0.056, argon atmosphere, sunlight source, and double quartz tube reactor. The maximum amount of equilibrium swelling (41 g g^?1) was achieved for MC-g-PAM with 34% monomer conversion. The resulting graft copolymers were characterized by FT-IR, SEM, and TGA. Synthesis of MC-g-PAM using TiO₂ nanoparticles (NPs) as the initiator was done successfully that shows the TiO₂ NPs are useable in graft polymerization of acrylamide monomers onto the MC under sunlight.     

Adsorption characteristics analysis of CO<Subscript>2</Subscript> and N<Subscript>2</Subscript> in 13X zeolites by molecular simulation and N<Subscript>2</Subscript> adsorption experiment

The adsorption characteristics of CO₂ and N₂ in 13X zeolites have been studied by the molecular simulation and N₂ adsorption experiment. It is found that the simulation results by Dreiding force fields are in an agreement with the published data. The influence of the σ and ε parameters of O_Z and Na⁺ on the adsorption performance is discussed. Then the optimized force field parameters are obtained. Specific surface area (S _B ) is calculated by simulation and experiment. Its relative error is just only 4.3 %. Therefore, it is feasible that S _B of 13X zeolites is obtained by the simulation methods. Finally, the impacts of pressure and temperature on adsorption characteristics are investigated. At low pressure, CO₂ adsorption in 13X zeolites belongs to the surface adsorption. As the pressure increase, the partial multilayer adsorption appears along with the surface adsorption. N₂ adsorption in 13X zeolites is different from that of CO₂. At low temperature of 77 K, two primary peaks are caused by the surface adsorption and multilayer adsorption respectively regardless of pressure variation. When the temperature is 273 K, the energy distribution curve appears undulate at low pressures. Then it becomes stable with the pressure increase. The surface adsorption plays an important role at the relative high pressures. The results will help to provide the theory guide for the optimization of force field parameters of adsorbents, and it is very important significance to understand the adsorption performance of zeolites.     

Synthesis and structural refinement of fully dehydrated fully Zn<Superscript>2+</Superscript>-exchanged zeolite Y (FAU), |Zn<Subscript>35.5</Subscript>|[Si<Subscript>121</Subscript>Al<Subscript>71</Subscript>O<Subscript>384</Subscript>]-FAU

The single-crystal structure of |Zn_35.5|[Si₁₂₁Al₇₁O₃₈₄]-FAU per unit cell, a = 24.794(1), dehydrated at 673 K and 1 × 10^?6 Torr, has been determined by single-crystal X-ray diffraction techniques in the space group \( Fd\bar{3}m \) at 294(1) K. The structure was refined using all intensities to the final error indices (using the 930 reflections for which F _o > 4σ(F _o)) R ₁ = 0.0448 (based on F) and wR ₂ = 0.1545 (based on F ²). About 35.5 Zn²⁺ ions per unit cell are found at an unusually large number of crystallographic distinct positions, six. The 0.5 Zn²⁺ ion per unit cell is located at the center of double 6-ring (D6R, site I; Zn(I)-O(3) = 2.642(3) Å and O(3)-Zn(I)-O(3) = 81.23(12) and 98.77(12)°). Two different site-I′ positions (in the sodalite cavities opposite D6Rs) are occupied by 14 and 3 Zn²⁺ ions per unit cell, respectively; these Zn²⁺ ions are recessed 0.67 Å and 1.02 Å, respectively, into the sodalite cavities from their 3-oxygens plane (Zn(I′a)-O(3) = 2.094(3) Å, Zn(I′b)-O(3) = 2.23(5) Å, O(3)-Zn(I′a)-O(3) = 110.32(12)°, and O(3)-Zn(I′b)-O(3) = 100.9(30)°). Site-II′ positions (in the sodalite cavities opposite S6Rs) are occupied by 6 Zn²⁺ ions, each of which extends 0.63 Å into the sodalite cavities from their 3-oxygens plane (Zn(II′)-O(2) = 2.164(3) Å and O(2)-Zn(II′)-O(2) = 112.00(12)°). Twelve Zn²⁺ ions are found at two nonequivalent sites II (in the supercage) with occupancies of 7 and 5 ions, respectively; these Zn²⁺ ions are recessed 0.52 Å and 0.96 Å, respectively, into the supercage from their 3-oxygens plane (Zn(IIa)-O(2) = 2.138(12) Å, Zn(IIb)-O(2) = 2.28(4) Å, O(2)-Zn(IIa)-O(2) = 114.2(10)°, and O(2)-Zn(IIb)-O(2) = 103.7(25)°).     

Hydrolysis of Phosphatidylcholine-Isoprostanes (PtdCho-IP) by Peripheral Human Group IIA,V and X Secretory Phospholipases A<Subscript>2</Subscript> (sPLA<Subscript>2</Subscript>)

Biologically active F- and E/D-type-prostane ring isomers (F₂-IP and E₂/D₂-IP, respectively) are produced in situ by non-enzymatic peroxidation of arachidonic acid esterified to GroPCho (PtdCho-IP) and are universally distributed in tissue lipoproteins and cell membranes. Previous work has shown that platelet-activating factor acetylhydrolases (PAF-AH) are the main endogenous PLA₂ involved in degradation of PtdCho-IP. The present study shows that the PtdCho-IP are also subject to hydrolysis by group IIA, V and X secretory PLA₂, which also have a wide peripheral tissue distribution. For this demonstration, we compared the LC/MS profiles of PtdCho-IP of auto-oxidized plasma lipoproteins after incubation for 1–4 h (37 °C) in the absence or presence of recombinant human sPLA₂ (1–2.5 µg/ml). In the absence of exogenously added sPLA₂ the total PtdCho-IP level after 4 h incubation reached 15.9, 21.6 and 8.7 nmol/mg protein of LDL, HDL and HDL₃, respectively. In the presence of group V or group X sPLA₂ (2.5 µg/ml), the PtdCho-IP was completely hydrolyzed in 1 h, while in the presence of group IIA sPLA₂ (2.5 µg/ml) the hydrolysis was less than 25% in 4 h, although it was complete after 8–24 h incubation. This report provides the first demonstration that PtdCho-IP are readily hydrolyzed by group IIA, V and X sPLA₂. A co-location of sPLA₂ and the substrates in various tissues has been recorded. Thus, the initiation of interaction and production of isoprostanes in situ are highly probable.     

Sacrificial PSS-doped CaCO3 templates to prepare chitosan capsules and their deformation under bulk pressure

To prepare microcapsules composed of chitosan (CS), a templating method is developed using poly(styrene sulfonate) (PSS)-doped porous calcium carbonate (CaCO₃) templates as sacrificial templates. First, CS is absorbed onto PSS-doped porous CaCO₃ templates, and then the absorbed CS is covalently cross-linked with each other by using glutaraldehyde. Porous CaCO₃ templates are dissolved with disodium ethylenediaminetetraacetate dihydrate and the resultant CS capsules ranged from 2 to 5 μm in diameter. Nitrogen adsorption–desorption analysis are applied to characterize the porous CaCO₃ templates, the BET surface area and total pore volume are 220 m²/g and 0.36 cm³/g, respectively. Field-emission scanning electron microscopy and transmission electron microscopy were used to characterize the CS capsules morphology. Confocal laser scanning microscopy images reveal that the capsules have been labeled with green fluorescein isothiocyanate. The gradual deformation of capsule in response to bulk osmotic pressure created by CS solutions has also been discussed.     

Dielectric study of side-chain liquid crystalline polyazomethine/fullerene C<Subscript>60</Subscript> nanocomposite

For side-chain liquid crystalline polyazomethine/fullerene C₆₀ nanocomposite (C₆₀ loading is 0.25 wt%), both real and imaginary components of the dielectric permittivity were investigated in wide regions of temperature and frequency. Analysis of frequency dependent permittivity allowed finding three relaxations (α, β ₁ and β ₂) in the nanocomposite. They were attributed to specific modes of molecular mobility. β-relaxations were described with the Arrhenius equation, whereas α-relaxation was described with the Vogel-Fulcher-Tammann equation. Anti-plasticization effect of the C₆₀ doping was shown to be manifested as an increase of the glass transition temperature of the nanocomposite as compared with that of the neat polymer.     

Effect of Cu promoter and alumina phases on Pt/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> for propane dehydrogenation

We investigated the effects of different Cu weight ratio on θ or γ-Al₂O₃ which were impregnated with platinum in terms of catalytic activity for propane dehydrogenation and physicochemical properties. 1.5 wt% Pt, 0-10 wt% Cu catalyst supported on θ-Al₂O₃ or γ-Al₂O₃ was prepared by incipient wetness co-impregnation. Enhanced Pt dispersion by increasing Cu contents in γ-Al₂O₃ supported catalyst was confirmed via XRD and XPS. Pt and CuO was separated in Pt-Cu/θ-Al₂O₃, but Pt-Cu alloy was identified after reduction treatment. Also, adding Cu in Pt/Al₂O₃ makes catalyst’s acidity lower and this property led to increased propylene yield in propane dehydrogenation. However, Pt₃Cu was not good for yield of PDH, which was confirmed in Pt-10Cu/θ-Al₂O₃ through XRD.     

Trisilanolphenyl-POSS nano-hybrid poly(biphenyl dianhydride-<Emphasis Type="Italic">p</Emphasis>-phenylenediamine) polyimide composite films: miscibility and structure-property relationship

A partially condensed polyhedral oligomeric silsesquioxane (POSS) compound, trisilanolphenyl-POSS (TSP-POSS) was prepared via a modified two-step procedure with phenyltrichlorosilane as the starting material. The solubility of the TSP-POSS in polyimide (PI) solvents, including N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc) was first evaluated. TSP-POSS could be dissolved in the test solvents with a solid concentration higher than 50 wt% and the obtained solution was stable both at room temperatures and in refrigerator at -18 °C for more than 1 month. TSP-POSS was then physically blended with a poly(amic acid) (PAA) obtained from 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) and para-phenylenediamine (PDA) with various adding proportions of 0, 5, 10, 15, 20, and 25 wt% (TSP-POSS in total solids). The obtained clear and homogeneous PAA/TSP-POSS solution was then thermally imidized at elevated temperatures to afford six PI/TSP-POSS composite films (PI-BP-0~PI-BP-25). For comparison, analogous composite films were prepared by blending TSP-POSS with another PI matrix, poly(pyromellitic anhydride-oxydianiline) (PI_PMDA-ODA) at the same hybrid proportion (PI-0~PI-25). TSP-POSS exhibited quite different miscibility with these two PI matrixes. All of the composite films based on PI_PMDA-ODA and TSP-POSS showed homogeneous nature and the films were optically transparent even at the high POSS loading of 25 wt%; however, the PI_BPDA-PDA analogues showed poor compatibility with the POSS additive when the adding proportion was over 10 wt%. PI-BP-20 and PI-BP-25 films were thoroughly opaque with the haze values of 100%. In addition, the residual weight ratio of the composite films at 760 °C in nitrogen increased from 62.0 wt% (PI-BP-0) to 74.1 wt% (PI-BP-25).     

Effect of Potassium on the Physiochemical and Catalytic Characteristics of V<Subscript>2</Subscript>O<Subscript>5</Subscript>/TiO<Subscript>2</Subscript> Catalysts in <Emphasis Type="Italic">o</Emphasis>-Xylene Partial Oxidation to Phthalic Anhydride

Abstract

Vanadia species formed on the surface depend on the K/V atomic ratio. At small K/V ratios, Raman spectra show the formation of the K-doped and K-perturbed monomeric species. At K/V?=?1, kristalline KVO₃ is mainly present on the surface. In situ high temperature XRD-results exhibit a promoting effect on the anatase to rutile phase transformation in the presence of 0.03 and 0.21 wt% potassium. Large amount of K (3 wt%) provides thermal stability of V/Ti/O catalyst and no transformation is found up to 600?°C. Reduction of vanadia K-doped vanadia catalysts is moved to higher temperatures than for the catalyst without potassium. The catalyst having 0.21 wt% K possesses the highest activity in o-xylene oxidation. Furthermore, the K-doped monomeric vanadia species in this catalyst leads to a promoted adsorption or a prevented desorption of phthalide, resulting in a decreased selectivity towards phthalide and CO_x and a increased PA selecticity.

Graphical Abstract

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Mild-thermal fabrication and phase conformation of chopped glass fiber-reinforced low-density unsaturated polyester resin with NH<Subscript>4</Subscript>HCO<Subscript>3</Subscript>

Chopped glass fiber-reinforced low-density unsaturated polyester resin product (CFR-LDUPRP) was fabricated utilizing chopped glass fiber and ammonium bicarbonate through an innovative mild-thermal process featuring an ideal phase conformation. Based on the mild-thermal mechanism and preliminary experiments, an orthogonal experiment was conducted to obtain the optimal conditions of CFR-LDUPRP fabrication. The optimal fabrication temperature of 76.0 °C, 20.00 phr of 3 mm chopped glass fiber, 2.50 phr of NH₄HCO₃ and 1.50 phr of tert-butylperoxy benzoate (TBPB) comprised the optimal conditions for CFR-LDUPRP fabrication. Under this condition, the density (ρ), compressive strength (P), and specific compressive strength (P_s) of CFR-LDUPRP specimen were 0.63?±?0.02 g cm^??3, 24.29?±?0.73 MPa, and 38.56?±?1.02 MPa g^??1 cm³, in the given order. The analyses of nonisothermal DSC and semi-quantitative FTIR revealed that NH₄HCO₃ neutralized the residual acid in the resin, leading to an early polymerization of resin and a prolonged curing process of UPR. The endothermic decomposition of NH₄HCO₃ and the vaporization of water enabled a mild-thermal mechanism, which was beneficial for the growth of bubbles and for the distribution of chopped glass fiber in the resin. Proper phase conformation of the resin, bubbles, chopped glass fiber together with cracks and microvoids in the resin matrix, characterized by SEM and ¹H NMR, facilitated the polymerization of UPR and improved properties of CFR-LDUPRP. Bubbles diameter ranged from 0.27 to 0.61 mm without linking or destroyed bubbles.     

Novel amphiphilic temperature responsive graft copolymers PCL-<Emphasis Type="Italic">g</Emphasis>-P(MEO<Subscript>2</Subscript>MA-<Emphasis Type="Italic">co</Emphasis>-OEGMA) via a combination of ROP and ATRP: synthesis,characterization, and sol-gel transition

A series of well-defined novel amphiphilic temperature-responsive graft copolymers containing PCL analogues P(αClεCL-co-εCL) as the hydrophobic backbone, and the hydrophilic side-chain PEG analogues P(MEO₂MA-co-OEGMA), designated as P(αClεCL-co-εCL)-g-P(MEO₂MA-co-OEGMA) have been prepared via a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The composition and structure of these copolymers were characterized by ¹H NMR and GPC analyses. The self-assembly behaviors of these amphiphilic graft copolymers were investigated by UV transmittance, a fluorescence probe method, dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses. The results showed that the graft copolymers exhibited the good solubility in water, and was given the low critical temperature (LCST) at 35(±1) °C, which closed to human physiological temperature. The critical micelle concentrations (CMC) of P(αClεCL-co-εCL)-g-P(MEO₂MA-co-OEGMA) in aqueous solution were investigated to be 2.0 × 10^?3, 9.1 × 10^?4 and 1.5 × 10^?3 mg·mL^?1, respectively. The copolymer could self-assemble into sphere-like aggregates in aqueous solution with diverse sizes when changing the environmental temperature. The vial inversion test demonstrated that the graft copolymers could trigger the sol-gel transition which also depended on the temperature.     

Degradation Treatment of 4-Nitrophenol by <Emphasis Type="Italic">Moringa oleifera</Emphasis> Synthesised GO-CeO<Subscript>2</Subscript> Nanoparticles as Catalyst

A facile microwave-assisted reaction was used to synthesize graphene oxide with cerium oxide nanoparticles (GO-CeO₂ NPs) from water extracts of Moringa oleifera flower. The one step microwave synthesis treatment was used for reduction of ceria atom to cerium oxide nanoparticles along with the reduction of graphene oxide. The synthesized GO-CeO₂ NPs were analysed by various analytical instrumentation techniques and we found the size of nanoparticles as 50 nm with a spherical shape. Further, the green synthesized GO-CeO₂ NPs were employed as a catalyst to reduce 4-nitrophenol and achieved a degradation rate of 95.45%.     

A novel biosensor based on electro-co-deposition of sodium alginate-Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>-graphene composite on the carbon ionic liquid electrode for the direct electrochemistry and electrocatalysis of myoglobin

A novel biosensor based on electro-co-deposition of myoglobin (Mb), sodium alginate (SA), Fe₃O₄-graphene (Fe₃O₄-GR) composite on the carbon ionic liquid electrode (CILE) was fabricated using Nafion as the film forming material to improve the stability of protein immobilized on the electrode surface, and the modified electrode was abbreviated as Nafion/Mb-SA-Fe₃O₄-GR/CILE. FT-IR and UV–vis absorption spectra suggested that Mb could retain its native structure after being immobilized in the SA-Fe₃O₄-GR composite film. The electrochemical behavior of the modified electrode was studied by cyclic voltammetry, and a pair of symmetric redox peaks appeared in the cyclic voltammograms, indicating that direct electron transfer of Mb was realized on the modified electrode, which was ascribed to the good electrocatalytic capability of Fe₃O₄-GR composite, the good biocompatibility of SA and the synergistic effects of SA and Fe₃O₄-GR composite. The electrochemical parameters of the electron transfer number (n), the charge transfer coefficient (α) and the electron transfer rate constant (k _s) were calculated as 0.982, 0.357 and 0.234 s^?1, respectively. The modified electrode exhibited good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) with wide linear range from 1.4 to 119.4 mmol/L, low detection limit as 0.174 mmol/L (3σ), good stability and reproducibility.     

To prepared fluorescent chitosan capsules by in situ polyelectrolyte coacervation on poly(methacrylic acid)-doped porous calcium carbonate microparticles

To prepare hollow microcapsules composed of native chitosan (CS), a templating method is developed using poly(methacrylic acid) (PMAA)-doped porous calcium carbonate (CaCO₃) microparticles as sacrificial templates. At first, CS was adsorbed onto PMAA-doped porous CaCO₃ microparticles, and then the adsorbed CS was covalently cross-linked with each other by using glutaraldehyde. After the dissolution of the templates, the resultant CS capsules ranged from 2 to 5???m in diameter. Nitrogen adsorption?Cdesorption analysis are applied to characterize the porous CaCO₃ templates, the BET surface area and total pore volume are 160 and 0.50?cm³/g. The structure and morphology of the CS capsules are characterized by FESEM and TEM. Confocal laser scanning microscopy images reveal that the capsules have been labeled with green FITC. The gradual capsule invagination in response to bulk osmotic pressure created by CS solutions has also been discussed.