Tailored interfaces in nanocomposites

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Rheological Properties of Organoclay Suspensions in Epoxy Network Precursors

This paper deals with the evolution of the state of dispersion of organically modified montmorillonites in epoxy or amine precursors. The epoxy prepolymer is a diglycidyl ether of bisphenol A (DGEBA) and the curing agent is an aliphatic diamine with a polyoxypropylene backbone (Jeffamine D2000). The clay dispersion is evaluated at the platelet scale (nanoscopic scale) from X-ray spectrometry [wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS)] and at the aggregates scale (microscopic scale) from rheological analysis. The organoclays used form gels in the monomers above the percolation threshold if no shear is applied and present a mechanical gel/sol transition when shear stress increases. Gel strength and viscosity at high shear rates are linked to the nanometric state of dispersion and reveal the existence of two different organizations depending on organoclay/monomer interactions: (i) When the clay shows good interactions with the monomer, a significant swelling of the clay galleries by the monomer is obtained. These swollen particles lead to formation of weak gels which after shearing give high relative viscosity fluids. (ii) When the clay develops poor interactions with the monomer, the clay tends to reduce its exchange surface with the monomer and leads to a strongly connected gel. Shear breaks down this physical network leading to a very low relative viscosity fluid composed of nonswollen particles keeping a high aspect ratio. (C) 2003 Elsevier B.V All rights reserved

Photopolymerization study and adhesive properties of self-etch adhesives containing bis(acyl)phosphine oxide initiator

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Evaluation of the versatile character of a nanoemulsion formulation

International audienc

A supramolecular ladderlike structure formed by the auto-assembly of benzene-1,3,5-triphosphonic acid

International audienceBenzene-1,3,5-triphosphonic acid 1, which is the phosphonic acid analogue of trimesic acid, forms a columnar packing in the solid state that is characterized by strong hydrogen bonds (contact distances O···O ranging from 2.55 to 2.60 Å) and π-stacking (d(Ar···Ar) = 3.89 and 3.69 Å) involving the aromatic rings, thus designing an organic supramolecular ladder structure by auto-assembly

Effect of two plasticizers on the physical aging of polylactide

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Hollow micropsheres-polypropylene blends : relationship between microsheres degradation and composites properties

International audienc

Kerosene flame behaviour of C/PEKK composite laminates: Influence of exposure time and laminates lay-up on residual mechanical properties

International audienc