Melt-Processable Nanocomposites Grafting-From Platelet Surfaces by Vapor-Assisted Surface Polymerization

One issue accompanying the melt-processing polymer/clay nanocomposites is the reaggregation of silicate platelets, which induces decreases in advantages of nanocomposites. To address this issue, vapor-assisted surface polymerization (VASP) method was applied with an initiator-attached and copolymerizable surfactant moiety-bound A-C18/C6MMT to obtain the exfoliated and intercalated nanocomposites using methylmethacrylate and styrene as vinyl monomers, respectively. The melt processing of the nanocomposites was carried out by a melt-compression molding method at 200°C. From XRD measurements, the C18/C6MMT-based nanocomposites showed no change in d-spacing even after melt processing, indicating the maintenance of the exfoliation and intercalation states. This maintenance must result from polymer chains grafting from the silicate layer surfaces, thus clearly confirming the anchoring effect of the copolymerizable surfactant moiety units

Effects of Deposition Parameters on the Electrochemical Behaviour of ZnO Thin Film

In this work, the electrochemical deposition of zinc oxide (ZnO) thin film on indium tin oxide (ITO) glass substrate from aqueous zinc nitrate was studied. Among the deposition parameters employed were deposition temperature, deposition potential, and deposition time. The morphology of the ZnO thin film was studied via FESEM.The electrochemical behaviour of the deposited ZnO thin flim was studied via cyclic voltammetry (CV) experiments. The deposition parameters lead to significant influence on the morphology and electrochemical behaviour of the thin films. The coverage area of the nanorods increased with the increase of temperature. Irregular structures of ZnO were obtained at lower deposition temperature at 60 °C. However, as the temperature increased to 90 °C, hexagonal shaped nanorods could be observed. As for the deposition potential, as the potential becomes more negative, more nucleation centers are activated and the rods are more vertical. The surface coverage is small, and increases with the deposition time. The compactness of the ZnO deposited is the highest with hexagonal rods covering the substrate at higher deposition time. The optimum electrochemical behavior of ZnO modified electrode was obtained from the deposition temperature of 60 °C using a deposition potential of -0.9 V for 900 seconds

Auto-Drawing and Functionalization by Vapor-Phase Assisted Polymerization on Solid Surface

Formation of two- and three-dimensional micro architectures with chemical functions was verified by photo-vapor phase assisted surface polymerization (VASP) of functional monomer vapors combined with an auto-drawing system manipulated by prescribed programs. The surface modification by the photo-VASP of styrene vapor progressed rapidly, and a fine lines-pattern of photo-mask was transcribed as the corresponding polymer accumulations on poly(methyl methacrylate) (PMMA) substrate surfaces. Substrate surface modified by photo-VASP of acrylic acid showed reversible changes in hydrophilic/hydrophobic properties according to repeating external chemical stimuli. The successive auto-drawing by photo-VASP of three kinds of monomer vapors was examined under spot illumination from a fine optical fiber on an X-Y stage manipulated by a prescribed program, resulting in the production of a pre-designed functional structure by successful accumulations of corresponding polymers on the substrate surface

Green polymer blends compatibilized with biomass derived-agents

The effect of soybean lecithin (SOLE) and acrylated epoxidized soybean oil (AESO) as biomass-based compatibilizer agents was studied for the purpose of enhancing the compatibility of environmentally friendly thermoplastic/elastomeric blend of poly (lactic acid) (PLA) and synthetic rubber (PI). PI was melt mixed 25:75 into PLA with and without compatibilizer agents by a twin-screw extruder. The content of compatibilizer agents was kept at 0.5 and 2%, rrespectively. The compatibility of SOLE and AESO was investigated with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and tensile test. From the thermal degradation and morphologic analysis, it was observed that SOLE was more effective in improving compatibility of PLA/PI blend in comparison with AESO. The inclusion of 0.5% SOLE into the blend system led to increment in the thermal stability, approximately, 10°C. Furthermore, a reduction of the size of PI islands distributed homogenously in the PLA matrix with the help of SOLE was observed, indicating the enhancement of interfacial adhesion. In other words, partially compatibilization took place resulting in the minimization of the dispersed PI island size

腎部分切除後に発生した腎偽性動脈瘤の1例

Although intraoperative hemorrhage is a well-recognized complication of open partial nephrectomy, postoperative hemorrhage caused by a renal artery pseudoaneurysm (RAP) after open partial nephrectomy is rare. We presented a case of RAP occurring in an 84-year-old man 3 weeks after right open partial nephrectomy for renal cell carcinoma. The pseudoaneurysmal branch was successfully identified and selectively embolized using percutaneous renal arterial angiography.腎偽性動脈瘤は腎生検, 腎外傷, 腎移植などに起因することが多いが, 腎部分切除術後に発生することは1%以下と稀である。われわれは腎部分切除術後3週間目に発生した, 腎偽性動脈瘤の1例を経験したので若干の文献的考察を加えて報告する。(著者抄録

Preparation of nanostructured TiO2 photoelectrode for flexible dye-sensitized solar cell applications

Nanocrystalline titanium dioxide (TiO2) thin film was successfully prepared by simple electrodeposition method from alkaline aqueous solution containing potassium titanium oxalate and hydroxylamine. Surface characterization of the electrodeposited films indicates the formation of crystalline TiO2. The dye solar cell constructed from dye-modified electrodeposited TiO2 film achieved an overall light-to-electricity conversion efficiency of 2.1 % under 1 sun illumination, indicating its high potential as a photoelectrode material for the DSCs

Effect of Ultrasonic-Assisted Extraction on Phenolic Content of Avocado

This study evaluate the effect of ultrasonic application in the extraction process on total phenolic content (TPC) of Hass avocado (Persea americana Mill) pulp. In this study, the solid/ solvent ratio of 1/30 (wt/ vol) and extraction temperature of 40 degree Celsius gave higher TPC value. This ratio and temperature was applied in the ultrasonic-assisted extraction (UAE) of avocado pulp. This study then compared the TPC obtained from the avocado pulp extract without involving ultrasonic and the TPC obtained from the UAE. Results showed that the TPC value of avocado pulp was significantly higher in the UAE (235.77 mg GAE/ 100g dried sample) compared to the TPC in the non-UAE (166.32 mg GAE/ 100g dried sample). The increase in the TPC was between ∼31 % and ∼41 % when 5 to 20 min of ultra sonication applied in the extraction. Ultra sonication duration of 15 min gave the highest TPC where the value was significantly higher compared to the other duration