Abstract: A series of hybrid materials involving cage-like octaaminopropyl polyhedral oligomeric silsesquioxane and Polyvinyl alcohol(OAPS/PVA) were prepared via solution blending method. The hybrid systems were characterized by FT-IR, scanning electronic microscopy(SEM), energy dispersive X-ray(EDS), differential scanning calorimetry(DSC), thermogravimetry analysis(TGA) and tensile test. The results show that hydrogen bond interactions are formed between OAPS and PVA and OAPS has a good dispersion in PVA matrix. The glass transition temperature(Tg) of OAPS/PVA increases from 53 °C to 61 °C, while the melting temperature(Tm) decreases from 180 °C to 173 °C with increasing OAPS content from 0 % to 12 %. The thermal stability of PVA main chain is improved by the addition of OAPS and the residue ratio also increases. The tensile strength of OAPS/PVA decreases from 39 MPa to 16 MPa, while the elongation at break of hybrid films increases from 148 % to 351 %.
Abstract: Photodegradation emerged as an effective technology for elimination of phenol and phenolic compound contaminants. In this paper, we developed an facile and scaled-up synthesis method for production of nanoscaled titanium dioxide (TiO2) photocatalysts doped with inorganic metallic ions of Sn, Zn, Fe, Cr, Mo, W, V, Ce, Au, Ag, Pt, and Pd. The obtained photocatalysts show relatively small sizes around 10 nm with highly crystallinity and narrow size distribution, and their efficiencies for photocatalytic degradation of phenol are greatly enhanced by doping the metallic ions. The photocatalytic efficiencies of nanoscaled TiO2 photocatalysts for phenol degradation could be improved to 93.6%, 89% and 98% by doping 2 wt.% Cr, 10 wt.% Ce, and 10 wt.% Pd, respectively, compared with that of the undoped nanoscaled TiO2 photocatalysts around 42.5%. The doped nanoscaled TiO2 photocatalysts may find potential application in treatment of phenol and phenolic compounds contaminants in industrial waste water.
Abstract: Inhalation administration requests the microparticles with appropriate average diameters and narrow diameter distribution. In this paper, the tetracycline microparticles suitable for inhalation administration were prepared successfully by Supercritical anti-solvent (SAS) process developed in recent years. A continuous SAS process had been adopted to prepare the micro-particles of tetracycline using ethanol as solvent and supercritical CO2 as anti-solvent. The effects of pressure, temperature, solution concentration and nozzle diameter on the morphology, size and size distribution of the particles were investigated. The results showed that tetracycline micro-particles with diameters range of 20nm to 40nm could be obtained by SAS continuous process when ethanol was used as organic solvent at the experimental operation parameters of the pressure of 15MPa, the temperature of 35°C, the solution concentration of 5mg/ml and the nozzle diameter of 75µm. The nano-particles of tetracycline prepared by the above continuous SAS process can be used for alveolus targeting drug delivery and the preparation of sustained-releases micro-spheres
Abstract: Bismuth selenide (Bi2Se3) hexagonal nanosheet crystals with uniform size were successfully prepared via a solvothermal method at 160°C for 22 h using bismuth trichloride(BiCl3) and selenium powder(Se) as raw materials, sodium bisulfite(NaHSO3) as a reducing agent, diethylene glycol(DEG) as solvent, and ammonia as pH regulator. Various techniques such as X-ray diffraction (XRD), field-emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HRTEM), and selected area electron diffraction (SAED) were used to characterize the obtained products. Results show that the as-synthesized samples are pure Bi2Se3 hexagonal nanosheet crystals. A possible growth mechanism for Bi2Se3 hexagonal nanosheet crystals is also discussed based on the experiment.
Abstract: The Co–B alloy can be prepared facilely by a solid-solid reaction of CoCl2•6H2O and KBH4 powders at room temperature. Various characterizations, such as the chemical analysis, inductively coupled plasma-atomic emission spectroscopy (ICP), powder X-ray diffraction, electron diffraction and TEM have been performed. The results indicate that the Co-B alloy obtained by the solid-solid reaction is amorphous nanoparticles. The composition of the alloy is Co1.36B. The average diameter of the Co–B alloy nanoparticles is 30nm–50nm. The room temperature solid-solid reaction is mainly a surface reaction. The direct solid solid reaction between the borohydride and some metal-salts is thermodynamically possible. This simple preparation method may also be used for the large-scale production of the amorphous nanoparticles of some metal-boron alloys.
Abstract: The two-step anodization process was adopted for the preparation of Al/Al2O3 (AAO) template with about 100 nm porous diameter. Then, the semi-terminated silica nanotubes were synthesized with the AAO template by the sol-gel method. The AAO template and semi-terminated silica nanotubes were observed by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The results showed that the porous diameter was increased with the increasing of the electrolyte concentration, the electrolysis temperature and the anodic oxidation voltage, respectively. The formation of semi-terminated silicon nanotubes might be important relationship with the method of embedding silane sol into the porous, drying temperature and drying time of AAO template with the sol-gel silica precursor.
Abstract: This study used carbon aerogels (CA) and phenolic resin in fixed proportations to produce nano high polymer resin, and used poly ehtylene oxide (PEO) as the modifying agent for phenolic resin to improve the mechanical properties of phenolic resin and promote the surface conductivity. The prepared nano high polymer resin and carbon cloth were made into nano-prepreg by using ultrasonic impregnation method, and a nano-prepreg composite material was prepared by using hot compacting and cut to test pieces to measure its mechanical properties and surface conductivity as well as the influence of temperature-humidity environment (85°C/168hr and 85°C/85%RH/168hr) on mechanical properties. The result showed that the surface conductivity increased by 64.55%, the tensile strength at room temperature increased by 35.7%, the flexural strength increased by 18.4%, and the impact strength increased by 101%. In hot environment (85°C/168hr), the tensile strength decreased by 23.8%, the flexural strength increased by 3.1%, and the impact strength increased by 84.6%. In high temperature-high humidity environment (85°C/85% RH/168hr), the tensile strength decreased by 29.6%, the flexural strength decreased by 17%, and the impact strength increased by 95.7%.Introduction
Abstract: Investigation on the antifeedant activity and toxicity of Catunaregam Spinosa (Rubiaceae) fruits revealed that the n-butanol fraction from methanolic extract of Catunaregam Spinosa fruits showed effective antifeedant activity and toxicity against the larvae of Pieris rapae and Plutella xylostella. Continued chemical investigation on the n-butanol fraction yielded five triterpenoids. Use of NMR, MS and sugar analysis gave structures of three triterpenoid saponins with branched monosaccharide chain as 3-O-[β-D-glucopyranosyl-(1→3)-β-D-6-O-methyl-glucuronopyranosyl oxy]-2β-hydroxy-olean-12-en-28-oic acid (1), 3-O-[β-D-glucopyranosyl-(1→2)-β-D-glucopyran -osyl]-olean-12-en-28-oic acid (2), 3-O-[β-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl- (1→2)-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl]-12-en-28-oic acid (3), and along with triterpenoids as Oleanolic acid (4), 3β,23-dihydroxy-olean-12-ene-28-oic acid (5), respectively.
Abstract: Carbon nanotubes is a current subject of intense research for their special structures, good conductivity, well mechanic and semicondcutor property. But the lack of solubility and the difficult manipulation in any solvents and aqueous have imposed great limitations to the use of carbon nanotubes. The chemical functionalization of can solved these problem, can be grouped into covalent modification and noncovalent modification. we review their researching progress in these and summarize their application.
Abstract: Silver plamitate was prepared with double jet method using palmitic acid, sodium hydroxide, silver nitrate as raw materials and PVP as surfactant. Effects of experimental conditions such as reaction system, reaction temperature and amount of PVP were investigated. The morphology of silver palmitate was characterized by scanning electron microscopy (SEM). Results show that the optimum reaction parameters are that the ratio of water to alcohol is 2:1, the reaction temperature is 75°C and the amount of PVP is 0.07g.