Polymer-Titanium hybrids obtained by radical polymerization and Sol-Gel process

The possibility to prepare hybrids made by poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA) and/or poly(ethyl acrylate) (PEtA) with TiO₂ was studied. The processes of polymer formation-radical polymerization and sol-gel process for inorganic network —were achieved simultaneously. Due to a high reactivity of titanium isopropoxide (TIP) in the sol-gel process, a complexant comonomer, allyl acetoacetate (AlAcAc), was used. Covalent bonds between polymer and inorganic chains were obtained by addition of trialkoxysilane derivates with vinyl (VTES) or methacryloyl (MPTS) groups. The presence of TIP inhibits the radical polymerization of vinyl acetate (VAc). The PVAc-TiO₂ hybrids were produced by the sol-gel process of TIP in the presence of pre-obtained PVAc. Except for VTES and MPTS, trialkoxysilane derivates with methyl (MeTES), octyl (OTES) and phenyl (PTES) groups were used. The thermal stability of hybrids is strongly affected by TiO₂ presence and by the type of trialkoxysilane derivates. The thermal stability of PVAc hybrids decreases in the presence of TiO₂ inorganic network. The glass transition temperature of polymers increases in the presence of the inorganic network.     

Selective Acetylation of Alcohols and Amines with Ethyl Acetate in the Presence of H<Subscript>6</Subscript>[PMo<Subscript>9</Subscript>V<Subscript>3</Subscript>O<Subscript>40</Subscript>] as the Catalyst

Summary. Acetylation of various alcohols and benzyl amine was tested in the presence of H₆[PMo₉V₃O₄₀], a mixed addenda heteropolyacid, in ethyl acetate under reflux condition. Phenols and anilines are not affected under the reaction conditions. Selective transestrification of alcohols can be achieved in the presence of phenol and aniline derivatives using this method.     

Synthesis and Characterization of a Novel Biomaterial： Maleic Anhydride-modified Poly（dl-lactic acid）

A novel modified poly(dl-lactic acid) (PDLLA) was obtained by covalently grafting of maleic anhydride onto the backbone of PDLLA, attempting to improve PDLLA‘s hydrophilicity and cell affinity and to provide reactive groups for further chemical modification. FTIR, ^13 C NMR and DSC were used to characterize the maleic anhydride-modified PDLLA.     

The Preparation and Characterization of Highly Dispersed PdO over Alumina for Low‐temperature Combustion of Methane

PdO/Al₂O₃ catalysts prepared by glow discharge plasma treatment followed by thermal calcination show a much higher dispersion and a better catalytic activity for methane combustion at relatively low temperatures. The dispersion of palladium active species by such plasma prepared catalysts is 29.7%, 5.4 times higher than that of conventional catalysts. XPS analysis indicates that a surface enrichment of Pd active species (PdO) has been achieved after plasma treatment. The surface atomic composition of PdO of plasma prepared catalysts reaches 10.5%. XRD characterization also confirms a wellcrystallized PdO phase present on the plasma prepared catalyst. The lightoff temperature of the plasma prepared catalyst is 370°C, 50°C lower than that obtained from the conventional catalyst.     

Synthesis of the Biomimetic Polymer： Aliphatic Diamine and RGDS Modified Poly（d,l-lactic acid）

A novel poly（d, /-lactic acid） （PDLLA） based biomimetic polymer was synthesized by grafting maleic anhydride, butanediamine and arg-gly-asp-ser （RGDS） peptides onto the backbone of PDLLA, aiming to overcome the acidity and auto-accelerating degradation of PDLLA during degradation and to improve its biospecificity and biocompatibility. The synthetic copolymer was characterized by FTIR, ^13C NMR and amino acid analyzer （AAA）.     

Determination of imazalil by on-line coupled capillary isotachophoresis with capillary zone electrophoresis

A simple, rapid and reproducible capillary isotachophoretic on-line coupled with capillary zone electrophoresis (CITP-CZE) method for the determination of IMz in food packaging extracts and its residues in apples is described. A good separation of the IMZ from other sample constituents was achieved within 15 minutes without any sample clean up. Method characteristics (linearity, accuracy, intra-assay and detection limit) were determined. Less amount of time involved, sufficient sensitivity and low running cost are the important attributes of CITP-CZE method.     

Kinetic Determination of Microquantities of Rutin by Perturbation of the Bray-Liebhafsky Oscillatory Reaction in an Open System

A kinetic method is described for the microquantitative (microconcentration/microvolume) determination of rutin based on potentiometric monitoring of the concentration perturbations of the Bray-Liebhafsky (BL) oscillatory reaction being in a non-equilibrium stationary state close to a bifurcation point. The experiments are carried out in an open reactor. The response of the matrix system to perturbations by different concentrations of rutin ethanolic solutions is followed by a Pt-electrode. In the concentration range between 7.8×10^–8moldm^–3 and 9.1×10^–6mol dm^–3, we found a linear dependence of the maximal potential shift, E_m, on the logarithm of the rutin concentrations. The unknown concentrations can be determined from the calibration curve up to an accuracy of ±5%. The detection limit is 3.6×10^–8mol dm^–3. The amount of required sample can be as small as 10µL.     

Analysis of fatty oil in Semen Ziziphi Spinosae by capillary gas chromatography

A simple and fast capillary gas chromatographic (CGC) method with flame ionization detection is developed for the analysis of fatty oil in Semen Ziziphi Spinosae. After methyl-esterification, eight components are identified by gas chromatography-mass spectrometry. The derivatization condition is investigated in order to validate this method. Palmitic acid and stearic acid are quantitated simultaneously. The limits of detection are 5.024 microg/mL for palmitic acid and 6.957 microg/mL for stearic acid, respectively. The limits of quantitation are 16.76 microg/mL for palmitic acid and 23.19 microg/mL for stearic acid, respectively. The percent recoveries of palmitic and stearic acid are 97.4% and 96.6%. CGC is shown to be a quick and informative tool for the analysis of fatty oil in Semen Ziziphi Spinosae.     

Theoretical study on conformational conversion of 1,3-dioxane inside a capsular host

The conformational conversion of 1,3-dioxane guest encapsulated inside a cylindrical capsular host was investigated with PM3 method and single point energies were evaluated by B3LYP method. When entrapped in the capsule, the guest tumbles were slower than that in the free condition. The influences of the inner phase of the capsule on the guest conformational conversion were discussed in detail.