Hybrid material for electromagnetic absorption

Patent (2012)

The present invention relates to a hybrid material (10) for absorbing electromagnetic radiation (60) and a method for making such a material. The hybrid material (10) comprises at least one grid panel (20 ... [more ▼]

The present invention relates to a hybrid material (10) for absorbing electromagnetic radiation (60) and a method for making such a material. The hybrid material (10) comprises at least one grid panel (20) of thickness t 1 having holes (25) traversing said thickness t 1 , at least one polymer composite material (30) of thickness t 2 filling at least partially the holes (25) of the at least one grid panel (20), said at least one polymer composite material (30) including a polymer matrix (40) and conductive particles (50) dispersed into said polymer matrix (40), characterized in that the internal surface of the holes (25) of the at least one grid panel (20) is metallic. [less ▲]

Process for preparing electromagnetic interference shileding materials

Patent (2012)

The present invention relates to a process for preparing an electromagnetic interference shielding material, or a precursor thereof, comprising a first polymer matrix and carbon conductive loads, said ... [more ▼]

The present invention relates to a process for preparing an electromagnetic interference shielding material, or a precursor thereof, comprising a first polymer matrix and carbon conductive loads, said process comprises the steps of: (a) Forming a reaction mixture comprising carbon conductive loads and a polymerizable medium said polymerizable medium comprising one or more monomers dissolved in a solvent, (b) Exposing the reaction mixture to polymerization conditions to polymerize said polymerizable medium and thus form a polymer, and (c) Forming a precipitate or an agglomerate of an electromagnetic interference shielding material made of less than 50 wt.% carbon conductive loads dispersed in the first polymer matrix formed in step (b), characterized in that, said polymer is insoluble in said solvent and in that a fraction of the polymer chains thus formed are grafted on part of the surface of the carbon conductive loads. [less ▲]

A convenient route for the dispersion of carbon nanotubes in polymers: Application to the preparation of electromagnetic interference (EMI) absorbers

in Polymer (2012), 53(1), 169-174

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates ... [more ▼]

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates and entraps all the CNTs. Thanks to the establishment of a suitable CNTs dispersion, this method promotes much higher electrical conductivity in the resulting nanocomposite than more conventional techniques, i.e. melt-mixing and co-precipitation. Moreover, the quantity of solvent required is much lower than in the co-precipitation method that makes this process industrially viable. One potential application of these nanocomposites has been demonstrated by the preparation of foams using the supercritical CO2 technology that present very high electromagnetic interference (EMI) absorbing properties since more than 90% of the incoming power being absorbed in the foam. [less ▲]

Foaming in CO2 sc medium as an efficient way to produce electromagnetic interference shielding materials

Conference (2011, June 30)

PMMA/carbon nanotube nanocomposites foams for EMI shielding application

Conference (2011, June 27)

Multifunctional hybrids for electromagnetic absorption

in Acta Materialia (2011), 59(8), 3255-3266

Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over ... [more ▼]

Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management. [less ▲]

PMMA/carbon nanotube nanocomposites foams for EMI shielding application

in PMSE Preprints (2011), 105

Routes for the preparation of advanced polymer/carbon nanoparticles based materials

Poster (2010, November 29)

Locating carbon nanotubes (CNTS) at the suface of polymer microspheres using poly(vinyl alcohol) grafted CNTS as dispersion co-stabilizers

Poster (2010, May 25)

Polymer composite material structures comprising carbon based conductive loads

Patent (2010)

The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 wt % to 6 wt % carbon ... [more ▼]

The present invention provides a polymer composite material structure comprising at least one layer of a foamed polymer composite material comprising a foamed polymer matrix and 0.1 wt % to 6 wt % carbon based conductive loads, such as e.g. carbon nanotubes, dispersed in the foamed polymer matrix. The polymer composite material structure according to embodiments of the present invention shows good shielding and absorbing properties notwithstanding the low amount of carbon based conductive loads. The present invention furthermore provides a method for forming a polymer composite material structure comprising carbon based conductive loads. [less ▲]