Facile Synthesis and Assemblies of Flowerlike SnS2 and In3+-Doped SnS2: Hierarchical Structures and Their Enhanced Photocatalytic Property

Novel flowerlike SnS2 and In3+-doped SnS2 hierarchical structures have been successfully synthesized by a simple hydrothermal route using biomolecular L-Cysteine-assisted methods. The L-cysteine plays an important role both as assistant and as sulfur source. Experiments with various parameters indicate that the pH values have a strong effect on the morphology of the assembly. Based on the experiments, a growth mechanical process was proposed. The synthetic samples were characterized by XRD, SEM, TEM (HRTEM), BET measurement, TGA, and XPS in detail.

Novel hybrid periodic mesoporous organosilica material grafting with Tb complex: Synthesis, characterization and photoluminescence property

A novel periodic mesoporous organosilica (PMO) material was synthesized through one-step co-condensation of 1,2-bis(triethoxysilyl)ethane (BTESE) and benzoic acid-functionalized organosilane (BA-Si) using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent under basic conditions. The materials were fully characterized by FTIR, XRD, N-2 adsorption-desorption isotherms and FESEM. FTIR spectra proved that BA-Si was successfully incorporated into the PMO materials (PMOs) via benzyl group as a linker. XRD and N-2 adsorption-desorption isotherms revealed the characteristic mesoporous structure with highly uniform pore size distributions. FESEM confirmed that the morphology of the PMOs was significantly dependent cri the molar ratio of two organosilica precursors.

Synthesis, characterization and optical property of flower-like indium tin sulfide nanostructures

We report a simple method for novel flower-like In4SnS8 nanostructure synthesis. A flower-like In4SnS8 nanostructure was synthesized via a one-pot hydrothermal route using the biomolecule L-cysteine as a sulfur source. The structure was characterized using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption analysis and photoluminescence spectra. This flower-like structure consists of crosslinked nanoflakes and possesses good thermostability and a high BET surface area.

Preparation and photovoltaic property of a new polyfluorene derivative/ZnO nanoparticles hybrid composites

A new kind of polyfluorene copolymers, poly(2,7-(9,9-dioctyl-fluorene)-alt-5,5 -(4',7'-di-2-thienyl-2',1',3',-benzothiadiazole) (PFDTBT), was prepared. The introduction of ZnO nanoparticles with perfect wurtzite crystal character into PFDTBT makes the resulted single-layer photovoltaic device to perform a significant photovoltaic response. Among the tested devices, the best performance is observed for that containing 60 wt% of ZnO nanoparticles, which has a photocurrent density of 1.17 mu A/cm(2), an open circuit voltage of 0.81 V. a fill factor of 0.09 and a power conversion efficiency of 0.009%. The results show that the polyfluorene derivatives/ZnO nanoparticles hybrid composites are excellent fluorescence and photovoltaic materials.

Integrated processing-structure-property analysis on rubber in-mold vulcanization

On the basis of the quantitative relationship among rubber processing, structure and property, the methodology of the integrated processing-structure-property analysis on rubber in-mold vulcanization is presented, and then the temporal evolution and spatial distribution characteristics of silicone rubber hot processing parameters, crosslinking structure parameters and mechanical property parameters are obtained by means of the finite element method. The present work is helpful for optimizing curing conditions, and then the design of rubber vulcanization processes according to certain requirements can be done.

Hot-corrosion behaviors of overlay-clad yttria-stabilized zirconia coatings in contact with vanadate-sulfate salts

A dense clad overlay with chemical inertness was achieved on top of the plasma-sprayed YSZ thermal barrier coatings by laser in order to protect them from hot-corrosion attack. The Al2O3-clad YSZ coating exhibited good hot-corrosion behavior in contact with salt mixture of vanadium pentoxide (V2O5) and sodium sulfate (Na2SO4) for a longtime of 100 h at 1173 K. The LaPO4-clad YSZ coating showed corrosion resistance inferior to the Al2O3-clad one. Yttria was leached from YSZ by reaction between Y2O3 and V2O5, which caused progressive destabilization transformation of YSZ from tetragonal (t) to monoclinic (m) phase. The chemical inertness of the clad layers and the restrained infiltration of the molten corrosive salts by the dense clad layers were primary contributions to improvement of the hot-corrosion resistances.

Influence of laser-glazing on hot corrosion resistance of yttria-stabilized zirconia TBC in molten salt mixture of V2O5 and Na2SO4

Plasma-sprayed 8YSZ (zirconia stabilized with 8 wt% yttria)/NiCoCrAlYTa thermal barrier coatings (TBCs) were laser-glazed using a continuous-wave CO2 laser. Open pores within the coating surface were eliminated and an external densified layer was generated by laser-glazing. The hot corrosion resistances of the plasma-sprayed and laser-glazed coatings were investigated. The two specimens were exposed for the same period of 100 h at 900 degrees C to a salt mixture of vanadium pentoxide (V2O5) and sodium sulfate (Na2SO4). Serious crack and spallation occurred in the as-sprayed coating, while the as-glazed coating exhibited good hot corrosion behavior and consequently achieved a prolonged lifetime. The results showed that the as-sprayed 8YSZ coating achieved remarkably improved hot corrosion resistance by laser-glazing.

Chemical bond characteristics, thermal expansion property and compressibility of AR(2)O(4) (A = Ca, Sr, Ba; R = rare earths)

Theoretical researches were performed on the CaFe2O4-type binary rare earth oxides AR(2)O(4) (A = Ca, Sr, Ba; R = rare earths) by using chemical bond theory of dielectric description. The chemical bond properties of these crystals were explored, and then the thermal expansion property and compressibility were studied. The theoretical values of linear thermal expansion coefficient (LTEC) and bulk modulus were presented. The calculations revealed that the LTECs and the bulk moduli do have linear relationship with the ionic radii of the rare earths. In the cases of Sc and Y, both the LTEC and bulk modulus values are larger than the lanthanide series. We attribute this to the difference in the electronic configuration between Sc (Y) and lanthanide series. For SrY2O4 and BaY2O4 crystals, the theoretical values of LTEC and bulk modulus agree well with experimental ones.

Synthesis and property of a novel sulfonated poly(ether ether ketone) with high selectivity for direct methanol fuel cell applications

Bisphenol monomer 4-carboxylphenyl hydroquinone (4C-PH) containing carboxyl groups was synthesized by diazotization reaction of p-aminobenzoic acid and 1,4-benzoquinone and subsequent reductive reaction. Copolymerization of bisphenol A, 4C-PH, sodium 5,5'-carbonylbis(2-fluorobenzene-sulfonate) and 4,4'-difluorobenzophenone at various molar ratios through aromatic nucleophilic substitution reaction resulted in a new sulfonated poly(ether ether ketone) containing pendant carboxyl groups (C-SPEEK). The structures of the monomer 4C-PH and copolymers were confirmed by FT-IR and H-1 NMR. Flexible and transparent membranes with sulfonic and carboxylic acid groups as the proton conducting sites were prepared. The dependence of ion-exchange capacity (IEC), water uptake, proton conductivity and methanol permeability on the degree of sulfonation has been studied.

Oligoaniline-Functionalized terpyridine ligands and their ruthenium(II) complexes: synthesis, spectroscopic property and redox behaviors

A series of oligoaniline-functionalized mono- and bis-topic terpyridine ligands, i.e. C6H5[N(R)C6H4](n)TPY (R = H, butyl, tert-butyloxycarbonyl; n = 1-4; TPY = 2,2':6',2"-terpyridyl) and TPYC6H4[N(R)C6H4](m)TPY (R = H, tert-butyloxycarbonyl; m = 2, 4), and the corresponding monoand bis-nuclear ruthenium(II) complexes have been synthesized and verified. The spectroscopic results indicate that two kinds of pi-pi* transitions from TPY and oligoaniline fragments of ligands strongly shift to lower energy, and the metal-to-ligand charge-transfer transition ((MLCT)-M-1) bands of all obtained complexes are considerably red-shifted (Delta lambda(max) = 22-64 nm) and their intensities become much more intense (approximately 4-6 times), compared with those of the reported complex [Ru(TPY)(2)](2+). Moreover, the spectroscopic properties of the ligands and complexes with longer oligoaniline units (n = 3, 4) are markedly influenced by the external stimulus, such as the oxidation and proton acid doping.

Synthesis and Characterization of Hyperbranched Poly(ether amide)s with Thermoresponsive Property and Unexpected Strong Blue Photoluminescence

A facile and efficient strategy for the syntheses of novel hyperbranched poly(ether amide)s (HPEA) from multihydroxyl primary amines and (meth)acryloyl chloride has been developed. The chemical structures of the HPEAs were confirmed by IR and NMR spectra. Analyses of SEC (size exclusion chromatography) and viscosity characterizations revealed the highly branched structures of the polymers obtained. The resultant hyperbranched polymers contain abundant hydroxyl groups. The thermoresponsive property was obtained from in situ surface modification of abundant OH end groups with N-isopropylacrylamide (NIPAAm). The study oil temperature-dependent characteristics has revealed that NIPAAm-g-HPEA exhibits an adjustable lower critical solution temperature (LCST) of about 34-42 degrees C depending on the grafting degree. More interestingly, the work provided an interesting phenomenon where the HPEA backbones exhibited strong blue photoluminescence.

Research on various factors influencing the moisture absorption property of sodium polyacrylate

Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties of moisture absorption, such as monomer concentration, dosage of initiator, and reaction temperature were systematically investigated. The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material, such as silica gel, and molecular sieve. The best reaction condition and formula are based on the orthogonal experiment design. The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g. The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis. The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency, followed by monomer concentration and reaction temperature, while other factors have less influence.

Effect of yttrium-rich misch metal on the microstructures, mechanical properties and corrosion behavior of die cast AZ91 alloy

Die cast AZ91-xYmm (x = 0-0.8 wt.%) magnesium alloys with excellent tensile properties and corrosion resistance behavior were successfully prepared by a simple addition of yttrium-rich misch metal (Ymm) to AZ91. Influences of Ymm on the microstructure, mechanical properties and corrosion behavior of AZ91 were investigated. The results showed that addition of Ymm to die cast AZ91 alloy could re. ne the microstructure including primary alpha-Mg and eutectic beta-Mg17Al12. When the content of Ymm reached 0.8 wt.% a small quantity of Al2Y phase would form. The tensile properties were improved greatly with addition of Ymm to AZ91. The creep rate of the AZ91-Ymm alloys, tested at 150 degrees C/50MPa, was one order of magnitude lower than that of AZ91. When addition of Ymm was more than 0.3 wt.%, the salt-spray corrosion resistance of AZ91-Ymm alloys could be 30-40 times of that of AZ91. The improvement of corrosion resistance with addition of Ymm was confirmed by the results of electrochemical polarization experiments. Mechanism of the improvement of mechanical properties and corrosion behavior caused by Ymm was also discussed.

Microstructures, mechanical properties and corrosion behavior of high-pressure die-cast Mg-4Al-0.4Mn-xPr (x=1, 2, 4, 6) alloys

Mg-4Al-0.4Mn-xPr (x = 1, 2, 4 and 6 wt.%) magnesium alloys were prepared successfully by the high-pressure die-casting technique. The microstructures, mechanical properties, corrosion behavior as well as strengthening mechanism were investigated. The die-cast alloys were mainly composed of small equiaxed dendrites and the matrix. The fine rigid skin region was related to the high cooling rate and the aggregation of alloying elements, such as Pr. With the Pr content increasing, the alpha-Mg grain sizes were reduced gradually and the amounts of the Al2Pr phase and All, Pr-3 phase which mainly concentrated along the grain boundaries were increased and the relative volume ratio of above two phases was changed. Considering the performance-price ratio, the Pr content added around 4 wt.% was suitable to obtain the optimal mechanical properties which can keep well until 200 degrees C as well as good corrosion resistance. The outstanding mechanical properties were mainly attributed to the rigid casting surface layer, grain refinement, grain boundary strengthening obtained by an amount of precipitates as well as solid solution strengthening.