Electromagnetic shielding properties

M. A. Soto-Oviedo, O. A. Aradjo, R. Faez, M. C. Rezende, and M.-A. DePaoh, Antistatic coating and electromagnetic shielding properties of a hybrid material based on polyanihne/ organoclay nanocomposite and EPDM rubber, Synth. Met, 156, 1249-1255 (2006). 

More recently, as pointed out earlier, doped PAn and blends of doped PAn have become commercially available in large quantities. They show superior electromagnetic shielding properties compared with previous materials [100,101]. The blends are easier to process than metal flake or fibre-filled polymers, and are non-abrasive. They also exhibit uniform and higher conductivities than is possible with carbon black fillers. It seems very likely that polythiophene blends that are currently being developed [102,103] may be used for similar purposes. 

The MWCNT-filled polystyrene composites have good electromagnetic interference shielding properties (Snow and Perkins, 2005). The shielding effectiveness of MWCNT-filled composites was frequency independent, and increased with the... 

Lazzeretti and coworkers175 calculated nuclear electric and electromagnetic shielding tensors for 1 and oxirane. These properties are related to atomic polar tensors and atomic axial tensors used by infrared and VCD spectroscopists. The authors demonstrated that they could obtain fairly accurate sum rules for atomic polar tensors and atomic axial tensors with relatively little computational effort. 

BB-102 Electromagnetic Shielding and Physical Property Test Experiments on Structural Foam Plastic Equipment Enclosures. 

Electroless deposition offers an attractive way of producing various fillers with a conductive surface or desirable magnetic properties, which can further be used in the production of composite materials with dielectric matrices for electromagnetic shielding. 

Material science interest focuses on potential applications of its specific electronic and band structure. Metal-like conductivities, semiconductor properties, photoconductivity and the nonlinear optical features of URPAC samples suggest devices for electromagnetic shielding, energy storage, microelectronics, optoelectronic and optooptical communication or optical computing. 

The references noted well demonstrate the ability to utilize polymer blend technology to achieve the desired balance of mechanical properties and conductivity. The promise of electrical conductive polymers with lower cost, processability, and mechanical durability can thus be envisioned for applications such as electrical dissipative coatings, printable circuits, electromagnetic shielding, resistive heating, conductive sheathing, battery applications, elastomeric conductors, fuses, electronic uses, sensors, specialty electrical devices for corrosive atmospheres, photovoltaic devices, catalysts, optical switches, and semiconductor devices. 

J. D. Sudha, S. Sivakala, R. Prasanth, V. L. Reena, and P. Radhakrishnan Nair, Development of electromagnetic shielding materials from the conductive blends of polyaniline and polyaniline-clay nanocomposite-EVA Preparation and properties. Compos. Sci. Technol., 69, 358-364 (2009). 

In addition, there is also the possibility of tailoring the properties of plain composites further by adding particles (such as metallic fillers [29,30], carbon nanotubes [31] or urea formaldehyde [32]) to the composite layers to create multifunctional and self-healing materials, von Klemperer and Maharaj [29] added copper and aluminium powder fillers to carbon fibre epoxy laminates to improve the electromagnetic shielding capacity of the composite panels. Blast tests on the laminates [30] showed that the laminates with filler particles outperformed their plain composite counterparts, although the margin was small. 

Other fibers may be used in POs, though some of these may be chosen more for their special properties. Basalt mineral fibers or Kevlar can provide extreme reinforcement for ballistics applications other fibers include metal fibers for electromagnetic shielding purposes (discussed in Chapter 6). However, as in the case of stainless steel fibers, just because an additive is in fiber form does not necessarily mean it provides meaningful mechanical property reinforcement, but it may provide the opposite of what is wanted [6-4, 7-57]. 

The synthesis of polyaniline can be carried out in aqueous HCI solution, by electrochemical oxidation, or in the presence of a chemical oxidant such as ammonium persulfate. The different forms of polyaniline can then be obtained by altering the current or the pH of the solution. The ability to tailor the process increases the potential for commercial application where the unique properties of a certain polyaniline are desired. Polyanilines are used as corrosion inhibitors and in the electromagnetic shielding of circuits, where they can protect against electrostatic discharge. 

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