Preparation and Characterization of Copper Chromium Oxide Nanoparticles Using Modified Sol‐Gel Route and Evaluation of Their Microwave Absorption Properties

Abstract

In this study, simple, broadband, robust, and affordable microwave absorbing nanocomposites are prepared using CuCr2O4 nanoparticles as guests and silicone rubber or poly(vinylidene fluoride) (PVDF) as host. Firstly, the pristine and modified CuCr2O4 nanoparticles are obtained by the conventional citrate gel method in the absence and presence of sucrose as a novel capping agent in the experimental steps. X‐ray powder diffraction (XRD) patterns confirms that the CuCr2O4 nanoparticles are synthesized. Moreover, morphologies, chemical functional groups, and optical properties are studied using field emission scanning electron microscopy (FE‐SEM), Fourier transform infrared (FT‐IR), and diffuse reflection spectroscopy (DRS), respectively. The vibrating sample magnetometer (VSM) analysis reveals weak magnetic properties for the nanoparticles and confirms that the capping agent change the magnetic properties. Finally, bare and modified copper chromium oxide nanoparticles are separately molded with silicone rubber or PVDF to compare dipole and interfacial polarization. Besides, using a vector network analyzer (VNA) along the x and ku‐band frequency, novel organic precursor effects on their microwave absorption properties are examined. According to the obtained results, the maximum reflection loss of the modified CuCr2O4/PVDF is −65.57 dB at 14 GHz with 2 mm thickness and the CuCr2O4/PVDF nanocomposite absorbs a bandwidth of 7.73 GHz more than 10 dB with a thickness of 2 mm. Interestingly, novel one type filler lead to significant microwave absorbing properties as well as organic capping agent reinforced maximum microwave absorption also PVDF improves absorption bandwidth.

Preparation of modified SrAl 1.3 Fe 10.7 O 19 nanostructures and evaluation of size influence on its optical and magnetic properties

“…Not only the electrostatic interactions between the metallic cations and unpaired electron of the hydroxyl and ether groups existing along HAC diminish agglomeration of the synthesised NPs but also the interaction of the oxygen as the electronegative atoms can regulate the crystallite size of the fabricated structures. Besides, the hydrogen bonding between the hydroxyl functional groups of the HAC and the hydroxylated intermediate modify the structure of the architected NPs [4, 7, 8, 31, 32]. The structure was formally originated from M‐type hexaferrite by cationic substitution.…”

“…It can be seen that all of the notches ascribed to the HAC chemical structure have been eliminated after heat treatments. The observed peak at 2330 cm −1 is associated of the adsorbed CO 2 stretching vibration at heterojunction interfaces [7, 31].…”

“…The energy bandgaps were estimated based on the Kubelka–Munk theory [33–35], suggesting diverse energy bandgaps for the samples. It should be noted the energy bandgap of the modified NPs was different owing to the more over hanging bonds, supplying the more discretised energy levels for the electron jumping [31]. The more light absorption is originated from the more surface area to volume ratio of the NPs due to their smaller structure.…”

“…The more grain boundaries boost the magnetic dead layers at interfaces diminishing the magnetic characteristics. Accordingly, the lower magnetic parameters of the bare NPs can be derived by their smaller size [4, 7, 8, 31].…”

Synergistic effect between CuCr2O4 nanoparticles and plasticizer on mechanical properties of EP/PU/CuCr2O4 nanocomposites: Experimental approach and molecular dynamics simulation

“…[27] A variety of synthetic methods has been employed in the preparation of the CuCr 2 O 4 NPs such as co-precipitation, solid state reaction, solution combustion process, sol-gel, hydrothermal methods, and so on. [28][29][30] Among these methods, the sol-gel autocombustion technique has emerged as noteworthy for the production of mixed metal oxides due to its high purity, good chemical homogeneity, and a synthesis of highly defect-free materials. [23] Herein, the CuCr 2 O 4 spinel NPs are prepared by the sol-gel auto-combustion method to act as nanofillers.…”