References of "Urbanczyk, Laetitia"
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See detailSupercritical CO2 and polycarbonate based nanocomposites: A critical issue for foaming
Monnereau, Laure; Urbanczyk, Laetitia; Thomassin, Jean-Michel ULg et al

in Polymer (2014), 55(10), 2422-2431

Supercritical carbon dioxide readily induced foaming of various polymers. In that context, supercritical CO2 was applied to carbon nanotubes based polycarbonate nanocomposites to ensure their foaming ... [more ▼]

Supercritical carbon dioxide readily induced foaming of various polymers. In that context, supercritical CO2 was applied to carbon nanotubes based polycarbonate nanocomposites to ensure their foaming. Surprisingly, efficient foaming only occurs when low pressure is applied while at high pressure, no expansion of the samples was observed. This is related to the ability of supercritical carbon dioxide to induce crystallization of amorphous polycarbonate. Moreover, this behaviour is amplified by the presence of carbon nanotubes that act as nucleating agents for crystals birth. The thermal behaviour of the composites was analysed by DSC and DMA and was related to the foaming observations. The uniformity of the cellular structure was analysed by scanning electron microscopy (SEM). By saturating the polycarbonate nanocomposites reinforced with 1 wt% of MWNTs at 100 bar and 100 °C during 16 h, microcellular foams were generated, with a density of 0.62, a cell size ranging from 0.6 to 4 μm, and a cellular density of 4.1 × 1011 cells cm−3. The high ability of these polymeric foams to absorb electromagnetic radiation was demonstrated at low MWNT content as the result of the high affinity of the polycarbonate matrix for MWNTs, and therefore to the good MWNTs dispersion. [less ▲]

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See detailHybrid material for electromagnetic absorption
Detrembleur, Christophe ULg; Molenberg, Isabel; Huynen, Isabelle et al

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 ▲]

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See detailHybrid material for electromagnetic absorption
Detrembleur, Christophe ULg; Huynen, Isabelle; Thomassin, Jean-Michel ULg et al

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 ▲]

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See detailMorphology and mechanical properties of bisphenol A polycarbonate/poly(styrene-co-acrylonitrile) blends based clay nanocomposites
Lin, Demiao; Boschetti-de-Fierro, Adriana; Alexandre, Michaël ULg et al

in Composites Science & Technology (2011), 71(16), 1893-1897

Two organic modified clays (Cloisite®30B (CL30B) and PCL/Cloisite®30B masterbatch (MB30B)) were used to improve the mechanical properties of polycarbonate (PC)/poly (styrene-co-acrylonitrile) (SAN) blends ... [more ▼]

Two organic modified clays (Cloisite®30B (CL30B) and PCL/Cloisite®30B masterbatch (MB30B)) were used to improve the mechanical properties of polycarbonate (PC)/poly (styrene-co-acrylonitrile) (SAN) blends. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements of the melt blended nanocomposites revealed that partially exfoliated and partially degraded structure was obtained and the clay platelets were located mostly in the SAN phase and at the two-phase boundary. Dispersion of the clay platelets is better when MB30B were used. The mechanical properties of the clays filled nanocomposites vary accordingly and when MB30B is used better mechanical properties can be achieved. Tensile strength increases 41% at maximum as the CL30B loading is 5 wt.%, while elongation at break decreases dramatically. Impact strength can be improved up to 430% compared to the pure blend when 1 wt.% MB30B was used. [less ▲]

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See detailMultifunctional hybrids for electromagnetic absorption
Huynen, Isabelle; Quievy, N.; Bailly, Christian et al

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 ▲]

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See detailExtrusion foaming of poly(styrene-co-acrylonitrile)/ clay nanocomposites using supercritical CO2
Urbanczyk, Laetitia; Alexandre, Michaël ULg; Detrembleur, Christophe ULg et al

in Macromolecular Materials and Engineering (2010), 295(10), 915-

Supercritical CO2 has been used as a blowing agent to foam poly(styrene-co-acrylonitrile)-based materials in a single screw extruder specially adapted to allow fluid injection. The cellular morphology ... [more ▼]

Supercritical CO2 has been used as a blowing agent to foam poly(styrene-co-acrylonitrile)-based materials in a single screw extruder specially adapted to allow fluid injection. The cellular morphology depends on foaming temperature, more regular cells being obtained with decreasing extrusion temperature. In a second step, a natural and an organomodified nanoclay have been added for the purpose of imparting some flame resistance to the foamed material. The filler efficiency in reducing sample combustion rate appeared to be dependent on its delamination level inside the matrix and better results were obtained when the organomodified clay was first delaminated in the polymer in an efficient twin screw extruder using water assistance, prior to foaming in the single screw extruder. [less ▲]

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