Research Article
Morphology and structure study of polygon ZnO nanorods: Biomedical applications
In this study, zinc oxide (ZnO) nanoparticles (NPs) were first synthesized using co-precipitation method in the presence of Zn(NO3)2.6H2O precursor and calcined at different temperature of 450 oC and 1000 oC. Samples were then characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The XRD study revealed the hexagonal wurtzite structure for annealed samples. SEM images showed tthat he morphology of the ZnO NPs changed from sphere-like shape to polygon shape by increasing temperature. The exact size of NPs were measured by TEM analysis about 40 nm for as-prepared samples. The EDS analysis demonstrated an increasing level of Zn element from 28.5 wt% to 50.8 wt% for as-synthesized and annealed samples, respectively.
Study of α-Fe₂O₃@ZnO nanoleaves: Morphological and optical study
In this paper, α-Fe2O4@ZnO nanoparticles (NPs) were synthesized by coprecipitation method in the presence of PVP and EG surfactants. The samples were charactrized by x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and fourier transform infrared spectroscopy (FTIR). The XRD results exhibited rhombohedral α-Fe2O3 and wurtzite structure of ZnO. The SEM images showed that the NPs changed from rod-shape to nanoleaves particles after heat treatment. The TEM studies displayed the formation of Fe2O3@ZnO core-shell of as-synthesized NPs. The stretching vibrations peaks in FTIR in the wavenumber of 532 cm-1 and 473 cm-1 ascribed to the Fe and Zn groups. The XRF data indicated decreasing of the Fe weight percent from 22 %Wt. to 25 %Wt., after heat treatment.
Heat treatment effect on the distribution of organic clay in polymer nanocomposites
In this paper, the effects of heat treatment temperature on the degree of exfoliation of organic clay under different compatibilizers were tested by using organic clay 93A, high density polyethylene (HDPE) and compatibilizer (PE-g-MA), polyethylene maleic anhydride copolymer (PEMA), maleic anhydride and polyethylene blend (MA/PE). The proportion of organic clay is 5 wt%, HDPE is 90 wt% and compatibilizer is 5 wt%. Temperature ranged from 210oC to 250oC, the position of [001] peak in the sample was determined, FESEM, TGA, FTIR and XRD was used to analyze the influence of temperature on the distribution behavior of clay in polymer system. The results are very significant for the industrial production of clay composite materials.
Development of advanced high strength steels using hydrogen quench continuous annealing technology
By using hydrogen quench continuous annealing technology, Stelco Inc. has developed a suite of Advanced High Strength Steel (AHSS) grades with tensile strength greater than 1000 MPa to meet standard automotive specifications and for unique customer requirements. These grades were optimized by correlating chemical composition and processing parameters with microstructures and mechanical properties. Dual-Phase 980 (Stelco trademarked STELMAXTM 980 DP), Multi-Phase 1180 (STELMAXTM 1180 MP), Martensitic Steel 1300 (STELMAXTM 1300 M) and 1500 (STELMAXTM 1500 M) products met strength and formability requirements with excellent flatness and surface quality. Hydrogen quench continuous annealing technology not only ensures all developed AHSS grades have consistent mechanical properties across the entire strip length (from strip head to tail) and width (from edge to edge), but also produces high product yield compared with other continuous annealing processes.
Jute fiber (hessian cloth)-reinforced unsaturated polyester matrix composites (50 wt% fiber) were fabricated by hand lay-up technique. Tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM), elongation at break (Eb%), and impact strength (IS) of the composites were found to be 42 MPa, 2.7 GPa, 36 MPa, 2.1 GPa, 3%, and 21 kJ/m2, respectively. On the other hand, TS, TM, BS, BM, and Eb% of E-glass mat reinforced unsaturated polyester resin (UPR) composite were found to be 70 MPa, 3.8 GPa, 80 MPa, 2.5 GPa, and 5%, respectively. Then E-glass/UPR based composites (50 wt% fiber) were fabricated and the mechanical properties were compared with those of the Jute/UPR based composites. It was observed that E-glass fiber-based composites showed almost double mechanical properties as compared to jute composites. The interfacial shear strength of the jute and E-glass fiber-based systems was investigated and found to be 21 kJ/m2 and 21.56 kJ/m2, respectively, measured using the single-fiber fragmentation test. After flexural testing, fracture sides of both types of the composites were studied by scanning electron microscope (SEM) and the results showed that poor fiber-matrix adhesion for Jute/UPR based composites when it compared to that of the E-glass fiber composites. However, it was found that the E-glass fiber based composite has better strength as compared to jute fiber composite.