Prsentation PowerPoint

Nanolatex based nanocomposites: control of the filler structure and reinforcement.

A. Banc1*, A-C. Genix1, C. Dupas, M. Chirat1, S.Caillol2, and J.Oberdisse11 Laboratoire Charles Coulomb, Universit Montpellier 2, Montpellier, France2 Institut Charles Gerhardt, Montpellier, France

1Mechanical reinforcement in nanocomposites?Microstructure

Filler networkDiluted regimeFFillerPercolation thresholdComposite properties Filler properties + Matrix propertiesMechanical properties

Jouault et al.Filler-filler interactions

Filler-matrix interactionsModel nanocomposites with tunable filler structuresi30 nmCollodal silica+DryingAnnealing

Water evaporationParticles deformationPolymer diffusionNanocompositeTUNABLE nanostructure: f(FSi, Si/ PEMA, Mw )PolyEthylMethacrylate (PEMA)Tg>TambNanolatexPEMA30 nm OR 200nmMw 20, 50 or 160 kg/mol3Effect of Rlatex/ RsiSmall Angle ScatteringI(cm-1)

kiksWave vector q= - kskilI(q)= f(F, Dr, P(q), S(q))F= Volume fractionDr=rScattering objects-rmatrixr=Scattering lengh densityP(q) = Form factorS(Q)= Structure factor

q(-1)P(q)S(q)I(q)Silica nanoparticles P(q)

=14 nm s=0,11

qmax

dP(q)*S(q)q-dfdf= fractal dimension5

0% 1% 3% 5% 10%

StructureRsilica~Rlatex~14 nmQ-2,4Colloidal solutions

Rsilica PEMA50 > PEMA160Rheological properties: nanocomposites

Two filler volume fraction regimes: -FFthreshold elastic material

Filler effect:-G at low frequency5%< Fthreshold Dynamical approaches of the mechanical reinforcementModel nanocomposites Various nanoparticle dispersions: well dispersed / fractal aggregates / porous network=> Novel structures with mixtures of latex bead sizesMechanical reinforcementMostly at low frequency aggregated filler reinforce better than the well dispersed oneQuantitative description of the filler structure :

Direct spaceReciprocal spaceTEMSAXSImage analysis + Simulation=> Behavior at large strains?