Carbon foam decorated with silver particles and in situ grown nanowires for effective electromagnetic interference shielding

Abstract

Carbon foam filled with silver particles was fabricated by a powder molding process using polyurethane as pore former, novolac resin as binder, coal-tar pitch as densification additive, and silver foils as a filler. High-temperature treatment at 1200°C, transformed the silver into spherical particles covered with in situ grown Ag nanowires. Their microstructure, electromagnetic interference (EMI) shielding effectiveness (SE), and shielding mechanism was investigated. It was found that the micron-sized silver foils converted into particles during heat treatment and strongly bonded in carbon matrix. The addition of silver significantly enhanced both conductivity and SE. Carbon foam containing 1.5 wt% silver exhibited very impressive total SE and dielectric loss tangent owing to the more conductive network of silver particles providing fast electron-transport channels. A maximum specific EMI SE value of 58.21 dB g -1 cm 3 at 12 GHz was achieved in the carbon foam at 1.5 wt% Ag loading. The dominant mechanism was absorption with only 6-10 % reflectance, resulting from the multiple reflections at interfaces inside the foam. Due to controlled attachment of silver particles and in situ reactions, this novel substrate has unique opportunities for future surface tailoring required in various commercial and aerospace fields.

Conformational changes on PMMA induced by the presence of TiO2 nanoparticles and the processing by Solution Blow Spinning

“…It is very well known that a wide range of properties can be tailored by the simple way of mixing different materials for which at least one of them had nanoscale dimensions. Among the different possibilities, polymers filled with different nanoparticles are very promising materials since, in many cases, apart from the easy procesability they present unique properties, such as the ones required for several specific applications like electrical or magnetic shielding or UV resistance [1][2][3][4][5][6], and coatings or adhesives with reduced coefficient of thermal expansion [7,8]. In general, these particular properties are due to the presence of the nanoparticles, where the polymer is acting as the matrix (also with its own properties) in which those particles are dispersed which, in addition, provides, in general, more consistency to the material.…”

Enhancement in graphitization of coal tar pitch by functionalized carbon nanotubes

“…The main reason of weakness of the (100) peak is due to the fact that the carbon atoms are joined by the strong covalent bonding in a graphene sheet. [30][31][32] In addition, it is clear that CTP coke has an amorphous structure at 1000 C by the position and width of the X-ray diffraction peaks. It can be deduced that the in-plane graphitic structure has ameliorated, and this specic structure developed by increasing the temperature.…”

In Situ Coating of Needle-like NiCo2O4 Magnetic Nanoparticles on Lightweight Reticulated Vitreous Carbon Foam toward Achieving Improved Electromagnetic Wave Absorption

“…Carbon foam, often termed as reticulated vitreous carbon (RVC), is a low-density, highly porous, glassy, electrically conducting (10–100 S m –1 ) material. It comprises predominantly of carbon as a major constituent (>95%).…”