References of "Alexandre, Michaël"
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See detailPreparation and properties of layered silicate nanocomposites based on ethylene vinyl acetate copolymers
Alexandre, Michaël ULg; Beyer, Günter; Henrist, Catherine ULg et al

in Macromolecular Rapid Communications (2001), 22(8), 643-646

(Nano)composites based on ethylene vinyl acetate copolymers (EVA) and montmorillonite modified by various alkylammonium cations were processed by mechanical kneading. Polymer intercalation and filler ... [more ▼]

(Nano)composites based on ethylene vinyl acetate copolymers (EVA) and montmorillonite modified by various alkylammonium cations were processed by mechanical kneading. Polymer intercalation and filler exfoliation were evidenced by X-ray diffraction and transmission electron microscopy, respectively. Nano-composites tensile properties showed that Young's modulus increases significantly even at very low content of the organo-modified filler while preserving high ultimate elongation and tensile stress. The matrix thermal stability in air was increased by 40°C and, interestingly, the obtained nanocomposites present flame retardant properties. TEM micrograph of the nanocomposite based on EVA3 filled with 5 wt.-% of Mont-2CN2C18. [less ▲]

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See detailPolymerization-filling technique: an efficient way to improve the mechanical properties of polyethylene composites
Alexandre, Michaël ULg; Martin, Eric; Dubois, Philippe ULg et al

in Chemistry of Materials (2001), 13(2), 236-237

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See detailPoly(e-caprolactone) layered silicate nanocomposites: effect of clay surface modifiers on the melt intercalation process
Pantoustier, Nadège; Alexandre, Michaël ULg; Degée, Philippe et al

in e-Polymers (2001), (9), 1-9

Nanocomposites based on biodegradable poly(e-caprolactone) (PCL) and layered silicates (montmorillonite) modified by various alkylammonium cations were prepared by melt intercalation. Depending on whether ... [more ▼]

Nanocomposites based on biodegradable poly(e-caprolactone) (PCL) and layered silicates (montmorillonite) modified by various alkylammonium cations were prepared by melt intercalation. Depending on whether the ammonium cations contain non-functional alkyl chains or chains terminated by carboxylic acid or hydroxyl functions, microcomposites or nanocomposites were recovered as shown by X-ray diffraction and transmission electron microscopy. Mechanical and thermal properties were examined by tensile testing and thermogravimetric analysis. The layered silicate PCL nanocomposites exhibited some improvement of the mechanical properties (higher Young's modulus) and increased thermal stability as well as enhanced flame retardant characteristics as result of a charring effect. This communication aims at reporting that the formation of PCL-based nanocomposites strictly depends on the nature of the ammonium cation and its functionality, but also on the selected synthetic route, i.e. melt intercalation vs. in situ intercalative polymerization. Typically, protonated w-aminododecanoic acid exchanged montmorillonite allowed to intercalate e-caprolactone monomer and yielded nanocomposites upon in situ polymerization, whereas they exclusively formed microcomposites when blended with preformed PCL chains. In other words, it is shown that the formation of polymer layered silicate nanocomposites is not straightforward and cannot be predicted since it strongly depends on parameters such as ammonium cation type and functionality together with the production procedure, i.e., melt intercalation, solvent evaporation or in situ polymerization [less ▲]

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See detailUse of metallocenes in the polymerization-filling technique with production of polyolefin-based composites
Alexandre, Michaël ULg; Martin, Eric; Dubois, Philippe ULg et al

in Macromolecular Rapid Communications (2000), 21(13), 931-936

In an updated version of the polymerization-filling technique, the surface of particulate fillers has been activated by metallocenes. Homogeneously filled polyolefins have accordingly been produced by the ... [more ▼]

In an updated version of the polymerization-filling technique, the surface of particulate fillers has been activated by metallocenes. Homogeneously filled polyolefins have accordingly been produced by the in situ copolymerization of ethylene and α-olefins, e.g., 1-octene and 1,9-decadiene. Different fillers have been successfully used, including inorganic particles with either an acidic surface (kaolin, glass beads, silica) or a basic surface (magnesium hydroxide, wollastonite), graphite and nickel particles. Hydrogen has proved to be efficient in reducing the molecular weight of the produced polymers. [less ▲]

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See detailPolymer-layered silicate nanocomposites: preparation, properties and uses of a new class of materials
Alexandre, Michaël ULg; Dubois, Philippe ULg

in Materials Science & Engineering. R: Reports (2000), R28(1-2), 1-63

A review with 115 refs. This review aims at reporting on very recent developments in syntheses, properties and (future) applications of polymer-layered silicate nanocomposites. This new type of materials ... [more ▼]

A review with 115 refs. This review aims at reporting on very recent developments in syntheses, properties and (future) applications of polymer-layered silicate nanocomposites. This new type of materials, based on smectite clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation, may be prepd. via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymn. and melt intercalation. The whole range of polymer matrixes is covered, i.e., thermoplastics, thermosets and elastomers. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfoliated nanocomposites where the sepd., individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filler level, usually inferior to 5 wt.%, such as increased Young's modulus and storage modulus, increase in thermal stability and gas barrier properties and good flame retardancy. [on SciFinder (R)] [less ▲]

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See detailPolyolefin-based composites by polymerization-filling technique
Dubois, Philippe ULg; Alexandre, Michaël ULg; Hindryckx, François et al

in Journal of Macromolecular Science - Reviews in Macromolecular Chemistry and Physics (1998), 38(3), 511-565

Dispersions of inorganic fillers within polymers are commonly designated as polymer-based composites. The properties of these materials are isotropic or anisotropic, depending on the geometry of the ... [more ▼]

Dispersions of inorganic fillers within polymers are commonly designated as polymer-based composites. The properties of these materials are isotropic or anisotropic, depending on the geometry of the filler particles and the effect of the processing conditions on their orientation. Fillers are used to improve some physicomechanical properties of the polymer, the material processability, or decrease the final cost. As a typical example, highly filled composites in which the filler concentration approaches the maximum packing fraction are known for their use in the shaping of ceramic articles. [less ▲]

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