Abstract: Poly(ether sulfone)s (PES) containing 25-75 mol % valeric acid were prepared with bisphenol A, bis(4-chlorophenyl)sulfone and 4,4-Bis(4-hydroxylphenyl)valeric acid using potassium carbonate in DMAc (dimethylacetamide) at 160 °C. Copolymers containing carboxylacid group were reduced to hydroxy group by BH3 solution 1M in THF and NaBH4 co-catalyst. Sulfonated poly(ether sulfone)s (S-PES) were obtained by reaction of 1,3-propanesultone and the reduced copolymer (PES-OH) with potassium t-butoxide. Composite membranes were prepared with copolymers and SiO2 nanoparticles(20 nm, 4-10 wt%). The composite membranes were cast from DMSO.A series of composite membranes were studied by 1H-NMR spectroscopy, differential scanning calorimetry (DSC), and thermo gravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol.
Abstract: The influences of preparing conditions on mechanical properties of the white mud (WM) / Konjac glucomannan (KGM) composite film (MKG) were investigated by orthogonal experiments. Zeta potential analysis and DSC were used to characterize the properties of WM and MKG. The results show that the mechanical properties of MKG films can be enhanced through proper modification. Optimized processing parameters of MKG film are described as following: the ratio of KGM, WM, benzoic acid, sodium dodecyl benzene sulfonate(LAS) and stearic acid was 100:14:2:0.24:0.14. 1.00 (wt) % of KGM powder was swelled in deionized water with WM modified by stearic acid, benzoic acid and LAS, stirred for 1.5 hour at 60°C and then paved on plate and dried at 40°C for 15 h to form the MKG film.
Abstract: Poly(ethersulfone)s carrying pendant sulfonated imide side group. The first step in the preparation involved nitration of poly(ethersulfone) (ultrason®-S6010), with ammonium nitrate and trifluoroacetic anhydride resulting in the nitrated poly(ethersulfone) (NO2-PES). In the second step, the nitro groups on polymer were reacted with tin(II)chloride and sodium iodide as reducing agents for creating the amino poly(ethersulfone) (NH2-PES). The imide-poly(ethersulfone)s (IPES) were obtained by reaction of phthalic anhydride and the amino-poly(ethersulfone) with triethyl amine. The sulfonated imide-poly(ethersulfone)s (SIPES) were prepared by chlorosulfonic acid. The different degrees of sulfonated imide units of poly(ethersulfone) were successfully synthesized by an optimized condition. The Sulfonated imide-poly(ethersulfone)s (SIPES) were studied by FT-IR, 1H-NMR spectroscopy and thermo gravimetric analysis(TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water. The ion exchange capacity (IEC) and proton conductivity of SIPES membranes were evaluated with increase of degree of sulfonation. The water uptake of synthesized SIPES membranes exhibit 30 ~ 65 % compared with 28 % of Nafion 211®. The SIPES membranes exhibit proton conductivities (25 °C) of 1.21 ~ 2.62´10-3 S/cm compared with 3.37´10-3 S/cm of Nafion 211®.
Abstract: Lead-free bismuth sodium zirconate powder with formula Na0.5Bi0.5ZrO3 was prepared by conventional mixed oxide method. Bismuth sodium zirconate (BNZ) powder with 10wt%Na2CO3 was calcined at 800 °C for 2 h dwell time. Investigation of the effects of re-calcination and dwell time on phase formation of powders was also carried out. The results revealed that re-calcination significantly affected the formation of single-phase BNZ powder. Phase characteristics were checked by X-ray diffraction (XRD). Powder Cell software was employed to simulate crystal structure of BNZ powder. It was found that BNZ powder most likely possessed an orthorhombic structure. SEM result showed its average particle size was 0.47 mm and composition measured EDX correlated with theoretical composition of BNZ.
Abstract: This work considers the CuO/La2O3/CeO2 nano-rare earth composite materials were synthesized by coprecipitation method with aqueous solutions of copper nitrate, lanthanum nitrate and cerium nitrate. The performance of the selective catalytic oxidation of ammonia to N2 (NH3-SCO) over a CuO/La2O3/CeO2 nano-rare earth composite materials in a tubular fixed-bed reactor (TFBR) at temperatures from 423 to 673 K in the presence of oxygen was reported. The catalytic redox behaviors were determined by cyclic voltammetry (CV). Further, cell cytotoxicity and the percentage cell survival were determined by using MTS assay on human fetal lung tissue cell (MRC-5). The experimental results show that the CuO/La2O3/CeO2 nanocomposite particles only minor cause cytotoxicity effect in cultured human cells.
Abstract: The La0.56Sr0.4Co0.2Fe0.8O3-δ (LSCF) perovskite cathode, substituted by Sr and Fe at the A and B sites, respectively, is a good candidate for intermediate temperature solid oxide fuel cell (IT-SOFC) applications. The powders were prepared by sol-gel method using various metal nitrates as starting materials. The adipic acid was used as a chelating agent and ethylene glycol as a dispersant. The gel precursor was heated at 700 °C for 4 h to obtain LSCF cathode powders. X-ray diffraction pattern showed the single phase of the perovskite structure. The microstructure of LSCF materials was observed by scanning electron microscopy which was loosely aggregated and could be ground easily into fine powders. The average particle size of the powders was found to be around 80-200 nm. TGA/DTA techniques exhibited the weight loss after high temperature process. It was found that no weight loss after 550 °C suggests the completion of combustion process.
Abstract: The transesterification in acetylated konjac glucomannan/ethylene vinyl acetate (AKGM/EVA) melting blend system with the presence of dibutyltin oxide (DBTO) catalyst was investigated by means of a torque rheometer during compounding. The characteristics of the products were evaluated by DSC and FT-IR. The glass transition temperature at about 179.4 °C was found in the DSC curve of AKGM-EVA, the equilibrium torque of AKGM/EVA with 0.25 wt% DBTO was lower than that without DBTO. The results showed that the transesterification took place in the AKGM/EVA blend system.
Abstract: Co4-xFexSb12-ySny skutterudites were synthesized by mechanical alloying and hot pressing, and thermoelectric properties were examined. The carrier concentration increased by doping and thereby the electrical conductivity increased compared with intrinsic CoSb3. Every specimen had a positive Seebeck coefficient. Fe doping caused a decrease in the Seebeck coefficient but it could be enhanced by Fe/Sn double doping possibly due to charge compensation. The thermal conductivity was desirably very low and this originated from ionized impurity-phonon scattering. Thermoelectric properties were improved remarkably by Fe/Sn doping, and a maximum figure of merit, ZT = 0.5 was obtained at 723 K in the Co3FeSb11.2Sn0.8 specimen.
Abstract: Half-Heusler alloys are one of the potential thermoelectric materials for medium to high temperature range application. As a part of fundamental study to establish processing route and to observe thermoelectric properties in undoped state, ZrCoSb was selected, processed and evaluated. In an attempt to produce a half-Heusler thermoelectric materials having ultra fine grain structures, ZrCoSb was synthesized by mechanical alloying of stoichiometric elemental powder compositions, and consolidated by vacuum hot pressing. Phase transformations during mechanical alloying and hot consolidation were investigated using XRD, SEM and EDS. Single-phase, half-Heusler was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. Thermoelectric properties as functions of temperature were evaluated in terms of Seebeek coefficient, electrical conductivity, thermal conductivity and the figure of merit for the hot pressed specimens. Mechanically alloyed half-Heusler phase, ZrCoSb, appeared to have a great potential as a thermoelectric materials in this study.
Abstract: The adsorption of Cd(II) ions from aqueous solution by sodium hydroxide-treated bamboo powder（STB） was studied in a batch adsorption system. Characteristics of STB were investigated by scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS). Factors influencing adsorption such as pH of the solution, adsorbent dosage, cadmium concentration and temperature have been studied. The adsorption process was relatively fast and equilibrium was achieved after 120 min, and the maximum adsorption of Cd(II) ions occurred at around pH 6.5. The equilibrium data were fitted using Langmuir, Temkin and Freundlich isotherm models to calculate isotherm constants. And the adsorption isotherm fitted well Langmuir isotherm, and the maximum adsorption capacity was 8.987 mg/g.