Advanced Materials Research Vols. 560-561

Abstract: Hyperbranched poly(diethynylbenzene-silane) (hb-PDEBS) was synthesized through polycondensation reaction of diethynylbenzene Grignard reagent (A₂) and trichlorosilane (B₃), and its structure was characterized by FT-IR, ¹H-NMR, GPC and Elemental Analysis. The degree of branching of hb-PDEBS was defined by ²⁹Si-NMR and calculated to be about 0.68. The curing behavior of hb-PDEBS was investigated by DSC. Thermal stability of cured hb-PDEBS was examined by TGA, and its residue at 1000°C under nitrogen was 80.6%. Hb-PDEBS displayed a strong absorption due to π-π^* transition and exhibited the most intensity structured emission with a maximum around 500 nm.

Abstract: Boron-silicon-containing arylacetylene polymer (PBSA) was synthesized through polycondensation reaction among diacetylenebenzene Grignard reagent, boron trichloride and dimethyldichlorosilane, and its structure was characterized by Infrared spectroscopy (FT-IR), Nuclear Magnetic Resonance spectroscopy (¹³C-NMR). The cure behavior of PBSA was investigated by using Differential Scanning Calorimetry (DSC), and the thermal and oxidative stability of cured PBSA were studied by Thermogravimetric Analysis (TGA) under nitrogen and air, respectively, the results indicated that ceramics derived from PBSA offer high thermal and oxidative stability.

Abstract: The kinetics of epoxidation of vegetable oils by traditional route (formic acid) or novel routes (peroxophosphatotungstate, methyltrioxorhenium) with hydrogen peroxide (H2O2, 30 wt. %) were investigated. The mathematical models describing the kinetics of epoxidation were developed. Using a linear fit method, kinetic parameters were estimated by fitting experimental data. The activation energy of the epoxidation reaction decreased in the following order: peroxophosphatotungstate > formic acid > methyltrioxorhenium. Other oils were also investigated under the same conditions. Results showed that the activation energy of epoxidation was in the order; rapeseed oil < fatty acid methyl ester < soybean oil < sunflower oil. Thermodynamic parameters of the epoxidation of vegetable oils were also obtained.

Abstract: Using one simple microwave synthesis method, take silver nitrate and vanadium(V) oxide as raw meterial to synthesize Silver Vanadate. The photocatalytic degradation of methyl orange under visible light irradation showed that the photocatalytic activities of microwave synthetic samples were better than those of samples produced by conventional hydrothermal technique. This experiment is to discuss the impact of these factors upon the catalyst performance through the control of the calcine temperature, the quantity of hydrogen peroxide, pH, the concentration of methyl orange and the quantity of catalyst. When the catalyst was calcined at 500 °C ,0.1 g, and 0.5 mL hydrogen peroxide joinded as well as pH was 2.0, the degradation ratio of Ag3VO4 for methyl orange of 100 mL 5 mg/L reached 91.49％ in 40 min.

Abstract: The procedure is described for the purification of acetonitrile to a level suitable for spectroscopic and chromatographic work. Rectification of chemical pretreated acetonitrile was performed on glass vacuum-jacketed column, filled with spiral-prismatic packing.

Abstract: A new approach for studying complex feedstock conversion with a hydrocracking catalyst is proposed in this work. The reaction was carried out in a batch reactor. Vapor and liquid samples were taken at different reaction times, both at operating conditions and after cooling to room temperature. Two-dimensional gas chromatography was used to characterize in detail the composition of condensed vapor and of liquid phases, while gas samples were analyzed by conventional gas chromatography. From room temperature conditions data, vapor fraction of the hydrocarbon mixture and compositions of each phase at reaction condition were calculated and validated. Following this methodology then allows a simple tracking technique for the study of complex hydrocarbon mixture reactions in liquid and vapor phases.

Abstract: To obtain new fine chemical and intermediate of functional polymer material, the acylation of acenaphthene with benzoyl chloride to 5-acetylacenaphthene catalyzed by silica-supported phosphotungstic heteropoly acid (PW/SiO2) was investigated. Pure 5-acetylacenaphthene was obtained and its structure was identified by GC/MS, FT-IR and 1H NMR spectra. The effects of experimental parameters on the catalytic acylation reaction and the possibility of reusability of PW/SiO2 catalyst were studied. Under optimun conditions, the yield and the selectivity of 5-acetylacenaphthene were up to 81.3 % and 93.6 %, respectively. PW/SiO2 shows well catalytic activity after running for 5 times. The experimental results indicate that PW/SiO2 is a recyclable and environmentally benign catalyst in the synthesis of 5-acetylacenaphthene.

Abstract: Anion exchange membranes based on poly(aryl ether oxadiazole)s (FPAEO) were prepared by quaternization of bromomethylated FPAEO with N-methyl imidazole. The structures of the obtained polymers were characterized and confirmed with 1H-NMR measurement. The physical and electrochemical properties of anion exchange membranes were also studied. The conductivity of FPAEO-xMIM membranes were almost higher than 10−2 S/cm at room temperature. In addition, TGA revealed that the AEMs based on imidazolium salts have excellent thermal stability. The experimental results suggested that the obtained AEMs may be potential membranes for anion exchange membrane fuel cells

Abstract: The solution behavior of aromatic polysulfonamide (PSA) in dimethylformamide (DMF) with the addition of CaCl₂ was studied by rheology and viscosity measurements. It is shown that no maximum in its intrinsic viscosity as a function of CaCl₂ concentration was observed and the relationship between η_sp and PSA concentration c is consistent with the predicted scaling of θ solvent for both DMF and DMF/4% CaCl₂. However, the intrinsic viscosity, zero shear-rate viscosity and specific viscosity of PSA/DMF/4% CaCl₂ were found larger than that of PSA/DMF, which could be related to the extending of PSA chain in solution due to the increase of the interaction between the PSA macromolecules and solvent with addition of CaCl₂.

Abstract: The composition and antioxidant activities of two polysaccharides PFCAⅢ and PFCCⅠ, isolated from Fructus corni, have been investigated. The monosaccharide components of PFCAⅢ were found to be rhamnose, arabinose and glucose in a molar ratio of 13.74: 50.54: 35.72, whilst PFCCⅠ was found to consist of xylose and glucose in a molar ratio of 18.8: 81.2. The weight-average molecular weights of PFCAⅢ and PFCCⅠwere 1.74×10⁴ and 7.57×10⁴ respectively. The polysaccharides showed potential antioxidant activity by scavenging superoxide anion (O₂⁻∙) and hydroxyl free radicals (OH∙) and this was confirmed by their ability to inhibit oxidation of axunge and gingili. The concentrations required to scavenge 50% of hydroxyl free radicals (EC₅₀) of PFCAⅢ and PFCCⅠ were 430μg/ml and 80μg/ml respectively, and the extents of scavenging O₂⁻∙ by 500μg PFCAⅢ and PFCCⅠwere 15.9% and 68.0% respectively. The polysaccharide PFCCⅠ shows much more significant antioxidant activity than PFCAⅢ. PFCCⅠ was mainly linked with β(1→4)-D-glucosyl with side chains including 1-linked β-D-Glc, 1,6-linked β-D-Glc and 1,4-linked β-D-Xyl with branching points at C-6 of 1,4-linked Glc in main chain. It had the potential to be exploited by the food and pharmaceutical industries in the future with further research on this polysaccharide.