Advanced Materials Research Vol. 717

Abstract: Poly (ethylene terephthalate)(PET)/Al₂O₃ nanocomposites via in situ polymerization were studied. The nanoparticle loading was varied from 0.3 to 1 wt.%. From the DSC results, no significant differences were recorded for melting temperatures. However, simple added PET/Al₂O₃ nanocomposites slightly changed to the lower melting temperature. Morphology of the nanocomposites has been examined by SEM. From the SEM results revealed that dispersed Al₂O₃ nanoparticles in the EG (ethylene glycol) during the polymerization can be well dispersed in PET matrix.

Abstract: Nanostructures materials were prepared from rice husk ash by carbon charcoal assisted. The rice husk ash mixed with coconut shell charcoal and Cu-Sn powder as the source materials. The mixtures materials were heated at 1100 °C under atmosphere of nitrogen with flow rate of 1 L/min. After the temperature was cool down, the prepared products were characterized by the stereo microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). The SEM images showed nanostructures materials such as nanoparticles, nanorods and nanowires. The XRD patterns indentified that the consisted of nanostructures materials were SiO₂-CuO phase.

Abstract: Duplex stainless steel are good combination of economy, weldability and toughness and are often selected where both strength and corrosion properties are crucial. The research was study the effect of post weld aging parameter on mechanical properties. The specimen was duplex stainless steel UNS31803 grade sheet of 10 mm thickness. This experimental study aims at 2³ factorial design optimizing various post weld aging parameters including solution temperature at 900 and 1,050 °C, post weld aging temperature at 650 and 850 °C and post weld aging time were set at 4 and 8 hour. The welded specimens were tested by hardness testing in heat affected zone and tensile strength testing. The result showed that both of solution temperature, post weld aging temperature and post weld aging time interaction on hardness and tensile strength at 95% confidential (P value < 0.05). Factors affecting the optimum were solution temperature 1050 °C, PWA temperature 850°C and PWA time 4 hr. at hardness optimum of 282.36 HV and tensile strength optimum of 109.37 kN. This research can bring information to the foundation in choosing the appropriate post weld aging parameters to duplex stainless steel welds.

Abstract: The influences of microporosity morphology on the flow stress behavior of 6063 alloy were investigated by isothermal compression test at 300°C-500°C and strain rate of 0.01-10s^-1. After 60% compression, the area fraction of microporosity of sample having lage microporosity decreases obviously. The flow stress increases with increasing strain rate and decreasing temperature. The flow stress stress behavior of 6063 alloy during hot compression can be described by a Zener-Hollomon parameter including Arrhenius item. The increasing of area fraction of microporosity decreases the deformation activiation energy Q.

Abstract: The article specifically deals with the compression molding technology and new possibilities to bring the whole technology to higher level in innovation. Identifies the methods and describe the best possible method to increase the productivity. Article introduces the compression molding technology, and how the preheated material can affect the compression time. The unreasonable higher the compression time is the less is the productivity. From measurements have been made conclusions, and the processed result are shown in charts and tables.

Abstract: The purpose of this research was to study phase transformation and photocatalytic properties of TiO₂ powders. TiO₂ powders were prepared by microwave-assisted sol-gel method. The prepared powders were refluxed at 18 W to 450 W for 1 h and dried at 180 W for 1 h by a conventional microwave oven. The phase transformations of powders were characterized by XRD and photocatalytic activities of powders were evaluated by UV-Vis spectrophotometer. The results show all samples reveal that only the anatase phase and has the crystallite size is 13.8, 10.3 and 9.2 nm when the refluxed at 180, 300 and 450 W. It was found that TiO₂ powders refluxed at 450 W were found to give the highest photocatalytic efficiency is about 90.06% under UV irradiation for 6 h.

Abstract: The surface properties of plasma-sprayed partial Y₂O₃ stabilized ZrO₂ coatings with different travel speed and powder-feeder rate of sprayed gun on aluminum substrates have been reported. Several coatings analytical parameters were studied and these factors affecting coating properties were carried out in the plasma-sprayed experiments. Experimental results have shown that the structure of the sprayed coatings that makes relatively diverse in texture for most of the coatings was examined by a SEM. The hardened strength with a low level of a slant of powder-feeder rate became significantly weaker as the travel speed was decreased. Interestingly, the structure of the specimens for the travel speed of 30mm/s is more homogenous than that of the others, indicating a coating with good homogenous structures, while the interfaced structure of the specimens for the powder-feeder rate of 25 mm/s is more homogenous than that of the others, indicating a coating with good adhesive structures. The tendency of the effect of travel speed of sprayed gun on the hardened surface of coatings at powder feeder rate of sprayed gun varied to 30g/min from 20g/min seems to be apparent.

Abstract: In this report, the chains of poly (aminophenylbornoic acid) (PAPBA) were grafted onto the surface of silica nanoparticles to obtain Si-g-PAPBA. Si-g-PAPBA was characterized through field emission scanning electron microscopy (FESEM), fourier transform infrared (FTIR) spectroscopy, UV-Vis spectroscopy and thermogravimetric analysis (TGA). Grafting of PAPBA chains onto silica surface was confirmed by TGA and FTIR spectroscopy.

Abstract: The comparative experiments for removing humic acid as environmental pollutant were conducted by adsorption on iron oxide, photooxidation in the presence of titanium dioxide catalyst and combined adsorption-photooxidation by iron-titanium mixed metal oxides, where all these active components were immobilized on polypropylene granules. The main purpose of the work was the combination of adsorption and photocatalytic oxidation processes to remove humic acid. The granules with iron-titanium mixed oxide for treating humic acid gave much better results with 1.2~3 times higher removal rates comparing to the other two single coated oxides at certain pH values. And the order of removal efficiency according to pH was the same as for single iron oxide-coated granules. The ratio 1:2 of iron oxide/titanium dioxide was found optimal for maximal decolorization of humic acid solution. The total organic carbon decrease of humic acid in each experiments, when it was pre-equilibrated with mixed oxides-coated granules in the dark for 30 min and without pre-equilibration, was very similar. The results suggested that the mechanism of humic acid removal may be not only a respectively combined adsorption and photooxidation by iron oxide and titanium oxides, but an enhanced photooxidation reaction as a result of concentrating humic acid on titanium oxide surface by iron oxide.

Abstract: Titanium dioxide was coated onto buoyant polypropylene granules. Titanium dioxide coated polypropylene granules (TCPG) had high mechanical and attritional stability as well as appreciable photocatalytic activity under solar irradiation. Chosen model pollutant, Methylene Blue (MB) could be totally decolorized and partially mineralized within 3 h of treatment. TCPG might successfully be applied as suspended in the column flow-through system. Degradation rates depended strongly on pH, initial dye concentration, and optimal media dosage, following pseudo-first-order kinetic model.