Entity

Time filter

Source Type


Al-Hartomy O.A.,King Abdulaziz University | Al-Hartomy O.A.,University of Tabuk | Al-Ghamdi A.,King Abdulaziz University | Dishovsky N.,University of Chemical Technology and Metallurgy of Sofia | And 3 more authors.
Journal of Elastomers and Plastics | Year: 2013

In this study, the influence of hybrid combination of fillers (carbon black in concentrations from 0 to 100 phr and conducting nickel (Ni) or cobalt particles in concentration 10 phr on the dielectric (dielectric permittivity and dielectric loss angle tangent)) and microwave (reflection coefficient, attenuation coefficient, and shielding effectiveness) properties of chloroprene rubber composites has been investigated in the wide frequency range (1-12 GHz). The results achieved showed that the hybrid combination of Ni powder and active furnace carbon black gives an opportunity of considerable increase in the dielectric permittivity and also a possibility for its adjustment varying carbon black content. The comparison in the behavior of prepared composites can be explained by the differences in some characteristics of two metals and influence of these differences on the real and imaginary parts of the complex dielectric permittivity and magnetic permeability. © The Author(s) 2012. Source


Al-Hartomy O.A.,King Abdulaziz University | Al-Hartomy O.A.,University of Tabuk | Al-Ghamdi A.,King Abdulaziz University | Dishovsky N.,University of Chemical Technology and Metallurgy of Sofia | And 4 more authors.
Fullerenes Nanotubes and Carbon Nanostructures | Year: 2014

In this study, the influence of carbon nanotubes (CNT) in concentrations from 2 to 10 phr on the dielectric (dielectric permittivity, dielectric loss angle tangent) and microwave (reflection coefficient, attenuation coefficient, shielding effectiveness) properties of nanocomposites on the basis of natural rubber has been investigated in the wide frequency range (2-12 GHz). Some additional investigations on the morphology and microstructure of the CNT used and studied composites have been carried out by transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The results achieved allow recommending carbon nanotubes as filler for natural rubber based composites to afford specific dielectric and microwave properties. © 2014 Copyright Taylor & Francis Group, LLC. Source


Al-Hartomy O.A.,King Abdulaziz University | Al-Hartomy O.A.,University of Tabuk | Al-Ghamdi A.A.,King Abdulaziz University | Al-Salamy F.,King Abdulaziz University | And 4 more authors.
Plastics, Rubber and Composites | Year: 2012

Natural rubber (NR) based nanocomposites containing a constant amount (50 phr) of standard furnace carbon black and carbon nanotube (CNT) at a concentration from 1 to 5 phr have been prepared. Their dielectric (dielectric permittivity and dielectric loss) and microwave properties (coefficients of absorption and reflection of the electromagnetic waves and electromagnetic interference shielding effectiveness) have been investigated in the 1-12 GHz frequency range. The results achieved allow recommending CNTs as second filler for NR based composites to afford specific absorbing properties. © Institute of Materials, Minerals and Mining 2012. Source


Al-Hartomy O.A.,King Abdulaziz University | Al-Hartomy O.A.,University of Tabuk | Al-Ghamdi A.,King Abdulaziz University | Al-Salamy F.,King Abdulaziz University | And 5 more authors.
Advanced Composite Materials | Year: 2013

In this study, the effect of carbon nanotubes (CNT) and graphene nanoplatelets (GNP) at various weight ratios between them on the dielectric (dielectric permittivity, dielectric loss angle tangent) and microwave (reflection coefficient, attenuation coefficient, shielding effectiveness) properties of nanocomposites on the basis of natural rubber has been investigated in the wide frequency range (1-12 GHz). Some additional investigations on the morphology and microstructure of the graphene particles and CNT used have been carried out by transmission electron microscopy and selected area electron diffraction. The results achieved reveal how by using the selected combinations between CNT and GNP the microwave and dielectric properties of natural rubber nanocomposites can be tailored depending on the need for real practical application. © 2013 Japan Society for Composite Materials, Korean Society for Composite Materials and Taylor & Francis. Source


Al-Hartomy O.A.,University of Tabuk | Al-Hartomy O.A.,King Abdulaziz University | Al-Solamy F.,University of Tabuk | Al-Ghamdi A.,King Abdulaziz University | And 3 more authors.
International Journal of Polymer Science | Year: 2011

In this paper, the dielectric and microwave properties of carbon black/siloxane rubber-based nanocomposites have been investigated in the frequency range from 1 GHz till 12GHz according to the content of carbon black and the frequency. It has been established that the increasing frequency and filler content lead to an increase in the relative permittivity and tangent of dielectric loss angle. At higher filler content, the effects become more pronounced, especially those upon dielectric loss. It has been also established that there are two well-distinguished areas in all dependences of microwave properties on frequency and filler content increasing. The first is between 1 and 8 GHz wherein the reflection and attenuation of microwaves do not change considerably with frequency and filler content alternation while shielding effectiveness worsens. The second area is between 8 and 12 GHz wherein the reflection and attenuation of microwaves increase drastically with the increasing frequency and filler content. Shielding effectiveness improves, too. It has been established that in all cases the degree of correlation between dielectric and microwave properties evaluated on the basis of the coefficients of correlation calculation is perfect. Copyright © 2011 Omar A. Al-Hartomy et al. Source

Discover hidden collaborations