4 results
Search Results
Now showing 1 - 4 of 4
Article Citation - WoS: 44Citation - Scopus: 54Preparation and Photocatalytic Activity of G-c3n4< Heterojunctions Under Solar Light Illumination(Elsevier Sci Ltd, 2020) Gundogmus, Pelin; Park, Jongee; Ozturk, AbdullahThe solar light sensitive g-C3N4/TiO2 heterojunction photocatalysts containing 20, 50, 80, and 90 wt% graphitic carbon nitride (g-C3N4) were prepared by growing Titania (TiO2) nanoparticles on the surfaces of g-C3N4 particles via one step hydrothermal process. The hydrothermal reactions were allowed to take place at 110 degrees C at autogenous pressure for 1 h. Raman spectroscopy analyses confirmed that an interface developed between the surfaces of TiO2 and g-C3N4 nanoparticles. The photocatalyst containing 80 wt% g-C3N4 was subsequently heat treated 1 h at temperatures between 350 and 500 degrees C to improve the photocatalytic efficiency. Structural and optical properties of the prepared g-C3N4/TiO2 heterojunction nanocomposites were compared with those of the pristine TiO2 and pristine g-C(3)N(4 )powders. Photocatalytic activity of all the nanocomposites and the pristine TiO2 andg-C3N4 powders were assessed by the Methylene Blue (MB) degradation test under solar light illumination. g-C3N4/TiO2 heterojunction photocatalysts exhibited better photocatalytic activity for the degradation of MB than both pristine TiO2 and g-C3N4. The photocatalytic efficiency of the g-C3N4/TiO2 heterojunction photocatalyst heat treated at 400 degrees C for 1 his 1.45 times better than that of the pristine TiO2 powder, 2.20 times better than that of the pristine g-C3N4 powder, and 1.24 times better than that of the commercially available TiO2 powder (Degussa P25). The improvement in photocatalytic efficiency was related to i) the generation of reactive oxidation species induced by photogenerated electrons, ii) the reduced recombination rate for electron-hole pairs, and iii) large specific surface area.Article Citation - WoS: 63Citation - Scopus: 70Processing and Properties of Boron Carbide (b4c) Reinforced Ldpe Composites for Radiation Shielding(Elsevier Sci Ltd, 2020) Avcioglu, Suna; Buldu, Merve; Kaya, Figen; Ustundag, Cem Bulent; Kam, Erol; Menceloglu, Yusuf Ziya; Kaya, CengizIn the present work, boron carbide (B4C) particles were synthesized with sol-gel technique following with heat treatment at 1500 degrees C in an argon atmosphere. 3-(Triethoxysilyl)-propylamine, a silane coupling agent, was doped on to the surface of synthesized B4C particles. The surface modified B4C particles were embedded in LDPE matrix in order to obtain flexible, lightweight and environmentally friendly shielding materials. The effect of surface functionalization and concentration of boron carbide on its distribution characteristics in the polymer matrix and its effects on the mechanical and neutron shielding properties of the composites are examined. The results showed that high purity-fully crystalline B4C powders with polyhedral-equiaxed morphology in the size range of 20 nm-500 nm were produced. It was found that even the very low amount (0.6-1.7 wt%) of incorporated nano/sub-micron B4C particles in LDPE matrix improved the neutron shielding (up to 39%), tensile strength (9.3%) and impact resistance (8%) of the composites.Conference Object Citation - WoS: 3Citation - Scopus: 4Production of Ultra-High Molecular Weight Polyethylene-Granite Composite Films by Gelation/Crystallization(Springer, 2016) Efe, Gozde Celebi; Ozaydin, Fevzi; Ucisik, Hikmet; Bindal, Cuma; Liang, HongThe present study reports on film of ultra-high molecular weight polyethylene (UHMWPE) containing 1 mass% granite composite produced by gelation/crystallization technique at 150 A degrees C from decalin solution. The morphology of UHMWPE-granite composite film was determined by using optical and scanning electron microscope, differential scanning calorimetry and Raman. Uniform dispersion of granite particles within ultra-high molecular weight polyethylene solution was the first step to achieve ultra-high molecular weight polyethylene-granite sheet samples with excellent properties. In differential scanning calorimetry analysis 50.1 % crystallinity of ultra-high molecular weight polyethylene-1 mass% granite composite was calculated from the endothermic peak area occurred around 142 A degrees C which correspond to melting point of composite. Mechanical property of ultra-high molecular weight polyethylene-1 mass% granite composite was tested with tensile test and shown to possess unique properties, in particular an increase of over 2.5 times in Young's modulus in comparison with pure ultra-high molecular weight polyethylene.Article Citation - WoS: 57Citation - Scopus: 68Mechanical Properties of B4c-sic Composites Fabricated by Hot-Press Sintering(Elsevier Sci Ltd, 2020) So, Sung Min; Choi, Woo Hyuk; Kim, Kyoung Hun; Park, Joo Seok; Kim, Min Suk; Park, Jongee; Kim, Hyung SunWe fabricated boron carbide-silicon carbide (B4C-SiC) composites by hot-press sintering without additives and evaluated the crystal phase, relative density, microstructure, and mechanical properties of the sintered body. When B4C and SiC were uniformly dispersed in the composite, crystal growth was inhibited, and a sintered body with a fine and uniform microstructure, with improved mechanical properties, was fabricated. The relative density of B4C-SiC composites sintered at temperatures lower than 2000 degrees C and 40 MPa of pressure exceeded 99.8%, and the bending strength and Vickers hardness at B4C 50 wt% were 645 MPa and 30.6 GPa, respectively.
