Magnetic and microwave absorbing properties of magnetite–thermoplastic natural rubber nanocomposites

Kong, Ing; Ahmad, Sahrim; Abdullah, Maimon; Hui, David; Yusoff, Ahmad Nazlim; Puryanti, Dwi

doi:10.1016/j.jmmm.2010.06.036

Cited by 231 publications

(129 citation statements)

References 20 publications

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“…All pastes used ordinary Portland cement as a binder and a water-to-cement ratio of 0.45. Three different mixtures were used [14], with different levels of nanomagnetite addition: a reference mixture and mixtures containing 0.5 wt% and 1 wt% Calculated in accordance with a formula: [15] using mixer. First, the dry material (cement and nanomagnetite powder) was placed in a bowl.…”

Section: Methodsmentioning

confidence: 99%

Influence of Magnetite Nanoparticles on Mechanical and Shielding Properties of Concrete

Lesbayev

Elouadi²,

Борботько

et al. 2017

Eurasian Chem. Tech. J.

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This paper presents an experimental study on the performance of shielding concrete with additives of magnetite nanoparticles. Two concretes with magnetite additives as well as one based concrete were tested. In order to achieve the high-performance concrete, all concrete mixes had a constant water/cement ratio of 0.45. In order to measure the mechanical properties, concrete samples were made in accordance with dimension such as 40 × 40 × 160 mm. But, for measurement of protective properties the concrete was made in accordance with dimension of rotary antennas such as 400 × 400 mm with a thickness of 10 mm. The nanoparticles Fe 3 O 4 were synthesized by chemical condensation method. XRD have shown the presence of cubic structure of Fe 3 O 4 spinel with crystallite size is equal to 130.0 Å. The TEM microphotograph shows that the Fe 3 O 4 nanoparticles are spherical, the range of sizes is 12-30 nm. The magnetic retardation suggests that the magnetite nanoparticles have superparamagnetic properties. This is explained by the fact that under the influence of external magnetic field, they are single-domain, in other words, they become uniformly magnetized throughout the volume. The additives of magnetite nanoparticles at a concentration of 0.5% mass have not a negative effect on flexural strength. The samples with additives of magnetite nanoparticles showed better shielding of microwave radiation in the frequency range from 0.7 GHz to 13 GHz. The maximum efficiency of suppression of electromagnetic disturbance is equal to 19.9 dB at a frequency of 1.5 GHz with a thickness of 10 mm.

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Section: Methodsmentioning

confidence: 99%

Influence of Magnetite Nanoparticles on Mechanical and Shielding Properties of Concrete

Lesbayev

Elouadi²,

Борботько

et al. 2017

Eurasian Chem. Tech. J.

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show abstract

“…As shown in Figures 9a and 10a, the real part of the permittivity of the specimens remained almost constant in the whole frequency range. The constancy means that there was a dominant polarization, in which the oscillation of the electric dipole moments was in phase or somewhat out of phase with the microwave frequencies [42]. Moreover, the atomic and electronic polarizations may take place within a period shorter than the period of a microwave signal.…”

Section: Electromagnetic Constitutive Parametersmentioning

confidence: 99%

“…That can introduce extra interfaces resulting in interfacial polarization. In addition, relaxation may occur at the MZF NPs/MWCNTs interfaces, which contributes to the dielectric loss [42]. The space-charge polarization can contribute an extra relaxation, resulting in an increase of the dielectric loss to some degree [43].…”

Section: Electromagnetic Constitutive Parametersmentioning

confidence: 99%

Manganese and Zinc Spinel Ferrites Blended with Multi-Walled Carbon Nanotubes as Microwave Absorbing Materials

et al. 2017

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Magnetic and dielectric materials can be blended to enhance absorption properties at microwave frequencies, although the materials may have relatively weak attenuation capabilities by themselves. The specific goal of this work is to enhance microwave absorption properties of materials with interesting dielectric behavior by blending them with magnetic materials based on transition metals. The synthesized Mn 1−x Zn x Fe 2 O 4 (x = 0.0 and 1.0) spinel ferrite nanoparticles (MZF NPs) were blended with commercial multi-walled carbon nanotubes (MWCNTs) in various proportions with a binder matrix of paraffin. This simple and efficient process did not cause a significant variation in the energy states of MWCNTs. MZF NPs were synthesized with a citric acid assisted sol-gel method. Their electromagnetic characteristics and microwave absorption properties were investigated. These properties were derived from the microwave scattering parameters measured via the transmission line technique by using a vector network analyzer (VNA) in conjunction with an X band waveguide system. The return loss (RL) values of the samples were obtained from the electromagnetic constitutive parameters (permittivity and permeability). The results indicate that the minimum RL value and the bandwidth change significantly with the amount of ferrite material in the blend. These results encourage further development of MWCNTs blended with ferrite nanoparticles for broadband microwave applications.

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“…Entre las principales problemáticas que pueden causar la EMI se encuentran la interrupción severa de dispositivos controlados electrónicamente o remotamente, generación de imágenes falsas (especialmente en radares náuticos y aéreos), degradación en la eficiencia, fiabilidad, tiempo de vida y seguridad de los equipos eléctricos, perturbación en canales de comunicación, reducción en el rendimiento de procesos automatizados, pérdida de energía, tiempo y recursos. Además, hoy en día es ampliamente discutido en todo el mundo los riesgos potenciales para la salud humana y los sistemas biológicos asociados con la exposición a campos electromagnéticos [2].…”

Section: Introductionunclassified

“…El blindaje puede lograrse reduciendo al mínimo la señal que pasa a través de un sistema, ya sea por la reflexión de la onda o por absorción y disipación de la radiación dentro del material [3]. Los parámetros que se deben tener en consideración para la producción de este tipo de materiales son: operatividad en una amplia banda de frecuencias, elevado coeficiente de absorción, baja reflectividad, bajo peso específico, pequeño espesor, así como adecuadas propiedades mecánicas y resistencia a la degradación ambiental [2,3]. De esta manera se pretende lograr dispositivos electromagnéticamente compatibles con su entorno, al evitar la interferencia electromagné-tica entrante y saliente [4,5].…”

Section: Introductionunclassified

Materiales compuestos de matriz polimérica usados para el blindaje de interferencia electromagnética

Posada

Téllez

Roa-Rojas

et al. 2017

Cien.Ing.Neogranadina

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<p>Este trabajo tiene como propósito revisar el estado del arte en la síntesis y caracterización de materiales de matriz polimérica reforzados con compuestos a base de carbón o ferritas para su uso como materiales atenuadores de interferencia electromagnética (EMI). Recientemente, este tipo de materiales han sido objeto de investigación debido a sus potenciales aplicaciones tecnológicas, economía y de ser además ambientalmente amigables, puesto que polímeros o cauchos reciclados se pueden utilizar para su fabricación. Estos compuestos pueden ser empleados en la producción de blindajes electromagnéticos, transductores, entrega focalizada de medicamentos, marcación de órganos, hipertermia magnética, etc. Para la fabricación de este tipo de materiales compuestos se usan refuerzos particulados, fibras o láminas y como matrices polímeros termoplásticos o termoestables, cauchos sintéticos o naturales. El método de producción de los compuestos (mezcla fundida, métodos químicos, etc.) influye en las propiedades eléctricas, magnéticas y electromagnéticas del material obtenido, debido a la relación de aspecto de los refuerzos: compuestos con elevada relación de aspecto de sus refuerzos tendrán mejores propiedades magnéticas, eléctricas y desempeño frente a la interferencia electromagnética. El blindaje electromagnético de estos materiales se cuantifica a través de la efectividad del blindaje (SE) o en otros casos a través de la pérdida reflectiva (RL). Una efectividad de blindaje de 30 dB corresponde a 99,9% de atenuación de la radiación electromagnética incidente. En todos los trabajos se comprueba que las propiedades del compuesto dependen de la cantidad y del tipo de refuerzo adicionado a la matriz.</p>

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Magnetic and microwave absorbing properties of magnetite–thermoplastic natural rubber nanocomposites

Cited by 231 publications

References 20 publications

Influence of Magnetite Nanoparticles on Mechanical and Shielding Properties of Concrete

Influence of Magnetite Nanoparticles on Mechanical and Shielding Properties of Concrete

Manganese and Zinc Spinel Ferrites Blended with Multi-Walled Carbon Nanotubes as Microwave Absorbing Materials

Materiales compuestos de matriz polimérica usados para el blindaje de interferencia electromagnética

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