Some Aspects of Nanoparticle Assembly and Polymer Dynamics in Rubber Systems.
Résumé
Rubber-based nanocomposites prepared by solid-phase mixing with precipitated silica nanoparticlesare typically strongly aggregated systems with different levels of spatial organization. The strategy thatwe developed several years ago to investigate such systems is based on the study of simplifiedindustrial samples with ingredients limited to a strict minimum. On the scale of a micrometricsimulation box, tens of thousands of nanoparticles are embedded in the matrix, and their dispersionstrongly affects the mechanical properties of the material – and which is reflected in the scatteredintensity. A statistical method based on a reverse Monte Carlo solution of this many-parameterproblem will be presented, showing that some key features like percolation can be described. [1]Another key feature of rubber nanocomposites refers to the influence of the filler surfaces on thepolymer dynamics, and some recent progress – including incoherent neutron spin-echo measurements– will be discussed. [2] Such results may be confronted to dielectric spectroscopy measurements whichin some cases are not conclusive due the impossibility to correctly resolve the α-relaxation in presenceof strong interfacial polarization processes. An original application of dielectric spectroscopy with asurprising measurement of the adsorption isotherm of coating agents onto silica buried in the polymermatrix will also be discussed. [3][1] Musino D, Genix A-C, Chauveau E, Bizien T, Oberdisse J, Nanoscale 2020, 12:3907.[2] Musino D, Oberdisse J, Farago B, Alegria A, Genix A-C, ACS Macro Letters 2020, 9:910.[3] Musino D, Oberdisse J, Sztucki M, Alegria A, Genix A-C, Macromolecules 2020, 53:8083.