Functionalized-CNT Polymer Composite for Microwave and Electromagnetic Shielding

In this research work, we studied the microwave properties of multi-wall carbon nanotube (MWCNT) surface functionalized with metallic oxides composites. Three different concentrations (5%, 10%, and 20%) of metallic oxides were used, namely cobalt, iron, and cobalt ferrite. The surface-decorated CNTS were impregnated into polyurethane (PU) matrix. The surface-decorated MWCNTs and the MWCNTs-PU composites were characterized using electron microscopy. The dielectric properties of the samples are studied using an open-ended coaxial probe technique in a wide frequency range of (5–50 GHz). The metallic oxide-decorated surface MWCNTs-PU composites demonstrated different microwave-frequency absorption characteristics depending on the concentration of the metallic oxides.

Production and Characterization of Amorphous Silica Nanoparticles from Coconut Shell and Coir

Silica has been produced from coconut coir and coconut shell because of the economic importance of coconut in India. The wastes are generated and disposed of indiscriminately while several are utilized for the energy source. The ash produced by burning them is usually discarded with a considerable amount of extractable silica present. Therefore, extraction of this silica was done using an environmentally friendly chemical approach to produce silica that could be used in several applications. The wastes were calcined at 700oC in a muffle furnace to get ash, treated with HCl to remove soluble metallic oxides, and after that sol-gelled to obtain silica gel. The gel was then dried at 65 oC for 24 hours and characterized using SEM, EDX, FT-IR, and XRD. Silica produced is amorphous with good absorbance potentials. The SEM micrographs show the particles in the Nano size range but with a high level of agglomeration.

The Calcination Temperature Effect on the Phase Formation of the PZT Ceramic: How the same Calcination Temperature, Result in Different Phase’s Formation

First, the metallic oxides of PbO, TiO2 and ZrO2 were mixed following (2, 1, 1) molar mass respectively. Then 4 samples were separated (S1, S2, S3 and S4). the first one S1 was subjected to calcination treatments at 600, 700 and 800 °C however, the S2 was treated at 700 °C only, the S3 at 800 °C and S4 at 850 °C. The X ray diffraction of the samples reveals important difference in the phases obtained, at 600 °C the quadratic riche phase of PbTiO3 was mainly observed on sample S1, after the treatment at 700 °C and 800°C, the same XRD patterns were obtained with the same peaks positions and the relative intensity. However the S2 revels different pattern from S1 at 700 °C relative to the formation of the Pb(Zr0.75, Ti0.25)O3 Rhombohedral riche phase. The S3 XRD results reveal also different pattern from S1 at 800 °C relative to the formation of Pb (Zr0.58, Ti0.42) O3 near the Morphotropic phase boundary (MPB) and the S4 confirm these finding. Thin films grown from the S1 and S4 used as target in the RF sputtering system, show important difference in the PZT stoichiometry obtained which is relative to Pb (Zr0.44, Ti0.56) located in the quadratic riche phase and Pb (Zr0.52, Ti0.48) O3 near the MPB respectively.

Green synthesis of nano-Al2O3, recent functionalization, and fabrication of synthetic or natural polymer nanocomposites: Various technological applications

Alumina nanoparticles (Al2O3 NPs) are one of the most extensively used nano-metallic oxides and nanofillers due to their fascinating properties in everyday applications. Furthermore, polymeric nanocomposites (PNCs) containing Al2O3 NPs...