RESUMO
Conductive polymer nanocomposites for electromagnetic interference (EMI) shielding are important materials that can be combat the increasingly dangerous radiation pollution arising from electronic equipment and our surrounding environment. In this work, we have synthesized polyaniline-copper nanoparticles (PANI-Cu NPs) by the copper salt based oxidative polymerization method at room temperature and then added with different concentration (0, 1, 3 and 5 wt%) in polystyrene polymer forming PS/ PANI-Cu nanocomposites films by means of the traditional solution casting technique. The formed PANI-Cu NPs were investigated by UV/Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM) and SEM/EDX elemental mapping techniques. On the other hand, the prepared PS/PANI-Cu nanocomposites films were evaluated by UV and SEM, the mechanical properties of the nanocomposites films were evaluated and showed an improvement by added PANI-Cu NPs up to 3 wt% and 50 kGy gamma exposure dose. The PS/PANI-Cu nanocomposites films were examined as electromagnetic interference shielding material. Electromagnetic shielding effectiveness of the produced nanocomposites were tested in the X-band of the radio frequency range namely from 8 to 12 GHz using the vector network analyzer (VNA) and a proper wave guide. All samples were studied before and after 50 kGy gamma-ray irradiation under the same condition of pressure and temperature. The results showed that the nanocomposites have improved shielding properties.
RESUMO
In the current work, cuprous oxide (Cu2O) nanoparticles coated with Tween 80 were successfully synthesized via the chemical reduction method. Nanocomposites composed of low-density polyethylene (LDPE) and different ratios of Cu2O nanoparticles were fabricated by the melt mixing process. 10% of ethyl vinyl acetate (EVA) as a compatibilizing agent was added to the molten LDPE matrix and the mixing process continued until homogenous nanocomposites were fabricated. To study the influence of ionizing radiation on the fabricated samples, the prepared species were exposed to 50 and 100 kGy of gamma rays. The synthesized Cu2O nanoparticles were investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). XRD and TEM analysis illustrated the successful formation of spherical Cu2O nanoparticles with an average size of 16.8 nm. The as-prepared LDPE/Cu2O nanocomposites were characterized via different techniques such as mechanical, thermal, morphological, XRD, and FTIR. Electromagnetic interference shielding (EMI) of the different nanocomposite formulations was performed as a promising application for these materials in practical life. The electromagnetic shielding effectiveness (SE) of the produced samples was measured in the X-band of the radio frequency range from 8 to 12 GHz using the vector network analyzer (VNA) and a proper waveguide. All the samples were studied before and after gamma-ray irradiation under the same conditions of pressure and temperature. The shielding effectiveness increased significantly from 25 dB for unirradiated samples to 35 dB with samples irradiated with 100 kGy, which reflects 40% enhancement in the effectiveness of the shielding.
RESUMO
Composites of polyvinyl chloride (PVC) with 2% calcium carbonate, 2% diethyl phthalate, 2% paraffin wax and 2% lead sulphate and different contents of antimony trioxide (Sb2O3) prepared by melting and irradiated with gamma ray have been considered. Assessment of the mechanical and thermal properties of the unirradiated and irradiated ï¬exible polyvinyl chloride (FPVC) were completed utilizing elasticity (TS), Elongation at break (Eb) and thermogravimetric analysis measurements. TS and thermal stability of FPVC displayed advanced improvement after addition of additives and this approach highlighted the efficiency of those ingredients on PVC. The compounding of FPVC with Sb2O3 in various extents was examined by FTIR, X-ray diffraction and scanning electron microscope methods. It is obvious that the presence of Sb2O3 begins impacting oxidative degradation, leading to a decrease in mechanical properties up to 10%. Moreover, a slight increase in the thermal stability of composites by exposure to ionizing radiation is apparently due to cross-linking of FPVC chains.
