Enhancement of Microwave Absorption Properties of Epoxy by Sol–Gel-Synthesised ZnO Nanoparticles (original) (raw)
Related papers
Chemistry Central Journal, 2015
Background Carbon nanotube (CNT) characteristics, besides the processing conditions, can change significantly the microwave absorption behavior of CNT/polymer composites. In this study, we investigated the influence of three commercial multi-walled CNT materials with various diameters and length-to-diameter aspect ratios on the X-band microwave absorption of epoxy nanocomposites with CNT contents from 0.125 to 2 wt%, prepared by two dispersion methods, i.e. in solution with surfactant-aiding and via ball-milling. Results The laser diffraction particle size and TEM analysis showed that both methods produced good dispersions at the microscopic level of CNTs. Both a high aspect ratio resulting in nanotube alignment trend and good infiltration of the matrix in the individual nanotubes, which was indicated by high Brookfield viscosities at low CNT contents of CNT/epoxy dispersions, are important factors to achieve composites with high microwave absorption characteristics. The multi-walle...
Materials Research-ibero-american Journal of Materials, 2018
The current research shows the effect of structural and morphological differences of multilayer carbon nanotubes (CNT) on radar absorbing materials (RAM) performance. Two CNT samples, from different manufacturers, had their morphological and structural aspects investigated by XRD, SEM and SEM-FEG analyses. CNT/epoxy resin based nanostructured composites were prepared and characterized by reflectivity measurements in the X-band. SEM results show the formation of agglomerates in the composites and the XRD patterns show structural differences between the two CNT samples. The best RAM performance (-25 dB) was determined for the nanocomposite based on the CNT with the smallest stacking layers (Lc = 26.9 Å) associated to the longest length of nanofilament (10-20 µm). This characteristic can have contributed to the formation of an interconnected network in the composite favoring electrical conductivity and dielectric properties, with the consequent increase of the wave attenuation.
Impact of ZnO nanoparticles on mechanical and dielectric properties of epoxy resin composites
Nucleation and Atmospheric Aerosols, 2023
The influence of nano filler content on the mechanical and dielectric properties of epoxy nanocompounds is investigated in this research. Epoxy is used as the matrix material. A different ratio of ZnO nanofiller was used (0.1,0.3,0.5,0 and 0.7 by weight), The test samples were prepared using an open die type, and tests were performed (three-point bending, stiffness, modulus of elasticity, and dielectric), and the mechanical and dielectric properties of the composite materials were determined and evaluated. With increasing the percentage of nanofiller material, the values of dielectric constant and loss factor decrease, while bending strength, flexural modulus, and stiffness increased, values It were before adding the nanofillers (1.05 MPa),(0.164 GPa),(79 N/mm 2) respectively, and after the reinforcement, they increased than they were to become (6.15 MPa),(1.636 GPa),(81 N/mm 2) respectively.
Journal of Physical Science
The MWCNT/ZnOw/epoxy composites have great potential as microwave absorbing material. The synthesis of ZnO whiskers (ZnOw) was carried out using precursors ZnSO 4 and Na 2 CO 3 via hydrothermal method with temperatures of 120°C, 160°C, 200°C, and 240°C. X-ray diffraction (XRD) and scanning electron microscope (SEM) were applied to find out the morphology and structure of ZnOw powder. The best results of the XRD and SEM-EDX at hydrothermal temperature of 160°C showed the best crystallinity of ZnO compound, that is at 2θ values of 31.
Journal of Materials Science: Materials in Electronics, 2018
The Mn:ZnO/epoxy nanocomposites (MZO-EP-NCs) resin samples are prepared using the ultrasonication method. This work deals with the systematic investigation of microstructural, optical and electrical properties of MZO fillers incorporating to the epoxy resin. These samples are characterized by scanning electron microscopy (SEM), X-ray diffraction and UV-Vis spectroscopy. SEM micrographs revealed that the as-prepared MZO nanocrystals are presented in the spherical clusters. X-ray diffraction indicates that the MZO-EP-NCs samples exhibit the presence of MZO nanocrystals peaks. Optical analyses showed a decrease in the band gap energy with increasing the MZO concentrations and a high UV-absorption of MZO-EP-NCs due to the light scattering due to the incorporating MZO particles in the epoxy. Such changes can be described by the shift of HOMO and LUMO band's transition in the studied samples. Our results support the correlation between structure and optical properties of the mentioned nanocomposites. At high electromagnetic waves, the dielectric permittivities are decreased linearly with the addition of MZO clusters compared to neat epoxy. The obtained optical parameters supporting the improvement of the UV shielding properties of MZO-EP-NCs samples.
Advances in Polymer Technology, 2015
The nanocomposite microwave absorbers are prepared from laminates of E glass/epoxy matrix with the incorporation of multiwalled carbon nanotubes (MWCNTs) and detonation nanodiamond (DND). Nanodiamond particles are used to effectively and uniformly disperse the carbon nanotubes in the polymer matrix, leading to a very homogenous mixture. The results showed that microwave absorption of nanocomposites increases with the increase in MWCNTs concentration in 11-17 GHz frequency range. The maximum loss of -28 dB was obtained at 14 GHz. The bandwidth corresponding to the reflection loss of −10 dB is 4.5 GHz. The mechanical properties are also improved after incorporating MWCNTs and DND in the composite. The tensile strength has been increased by ß113% after the addition of 1.0 wt% MWCNTs and 0.1 wt% DND. The morphological investigation demonstrated that coating of MWCNTs on the surface of the woven glass fibers in the presence of DND resulted in uniform dispersion of nanotubes throughout the matrix with the formation of connected networks that helps in electrical conduction and load transfer between the nanofillers and the matrix. The role of MWCNTs and DND particles in enhancing the electromagnetic absorption and mechanical properties of the nanocomposite laminates is explained. C
The influence of ZnO nanoparticles on the dielectric properties of epoxy resin
APPLIED PHYSICS OF CONDENSED MATTER (APCOM 2019)
Interesting electrical properties represent the epoxy nanocomposites, because the addition of nanofillers to a pure epoxy resin demonstrate several advantages opposite to pure epoxy resin without nanofillers. In the last 20 years, the dielectric properties (the complex permittivity and dissipation factor) of epoxy nanocomposites had been evaluated and the results clearly show that they are lower than that of base epoxy and microcomposites when insulating oxides were used as the fillers. Nowadays the epoxy and epoxy based composites are preferred insulating materials for many electrical applications. The influence of the various concentrations of ZnO nanoparticles in epoxy resin Vukol 022 on the changes of the complex permittivity and dissipation factor has been measured at the temperature range from 20 °C to 120 °C by a capacitance method in the frequency ranges from 1 mHz to 1 MHz. In this contribution, we present a study of the influence of 1,0 wt.% and 5,0 wt. % concentrations of ZnO nanofillers on the dielectric properties of the epoxy resin. From the frequency dependence of dissipation factor, α-relaxation process and its shift to lower frequencies with ZnO fillers were observed.
Comparison of Microwave Absorption Properties Between BaTiO3/Epoxy and NiFe2O4/Epoxy Composites
Microwave absorption properties of Epoxy/Nickel Fer- rite (NiFe2O4) and Epoxy/Barium Titanate (BaTiO3) composites were investigated and compared in the 1– 14 GHz. Epoxy/filler particles (NiFe2O4 and BaTiO3) composites were prepared with 85/15 mixture ratios via Ultrasonic Probe Sonicator method in solution. The complex permittivity (E0-E00) and permeability (l0-l00) of the composites have been measured at different microwave frequencies in 1–14 GHz via vector network analyzer (Keysight N9926A). The reflection loss (RL) of composites was calculated and evaluated from cam- plex permitivity and permeability. The obtained results show that both composites exhibit the large RL and broadband within the frequency range from 1 to 14 GHz for different thickness. Epoxy/BaTiO3 showed a better microwave absorption at the range of 6–7.2 GHz for 7 and 6 mm, at the range of 7.4–9.1 GHz for 5 mm. However, the Epoxy/NiFe2O4 exhibits the largest RL and the widest bandwidth than those obtained from Epoxy/BaTiO3 composite. POLYM. COMPOS., 00:000–000, 2017. VC 2017 Society of Plastics Engineers
ANALYSIS OF MICROWAVE ABSORBING PROPERTIES OF EPOXY MWCNT COMPOSITES
Progress In Electromagnetics Research Letters, 2014
In the ongoing search for new materials for microwave absorption applications, Carbon Nanotubes deserve a special consideration due to their outstanding properties. In this paper, microwave absorbing properties of epoxy resin based composites containing commercial Multi Walled Carbon Nanotubes used as fillers have been analyzed. The complex permittivity of the composites was measured in a wide frequency band (3-18 GHz). The absorbing properties of a single-layer absorber backed by a metallic plate considering several concentration of CNTs was simulated taking into account the measured permittivity.