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Structure, vibration, relaxations dans les systèmes désordonnés
(39) Production(s) de l'année 2017
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Poroelastic Theory Applied to the Adsorption-Induced Deformation of Amorphous Silica 
Auteur(s): Weigel C., Polian Alain, Kint M., Rouquette Jérome, Haines Julien, Foret M., Vacher R., Ruffle B., Coasne Benoit
Ouvrage: (2017) 14-19
Ref HAL: hal-01909090_v1
DOI: 10.1061/9780784480779.003
Exporter : BibTex | endNote
Résumé: Under a high pressure of helium, the volume change of amorphous silica is much smaller than expected from its elastic properties. This is due to helium insertion in the free volume of the glass network. Here, we report spectroscopic experiments using either helium or neon as penetrating pressurizing media and molecular simulation that indicate a relationship between the amount of gas adsorbed and the strain of the network. A generalized poromechanical approach, describing the elastic properties of microporous materials upon adsorption, is shown to successfully describe the physics of deformation of such silica glasses in which the free volume exists only at the sub-nanometer scale.
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Impact of formulation on multi-scale structure and segmental dynamics in simplified industrial nanocomposites
Auteur(s): Musino D. , Genix A.-C., Chaussée Thomas, Meissner Natalia, Bizien Thomas, Alegria Angel, Oberdisse J.
(Affiches/Poster)
European Colloid and Interface Society Conference 2017 (ECIS) (Madrid, ES), 2017-09-03
Ref HAL: hal-01876982_v1
Exporter : BibTex | endNote
Résumé: In recent years, materials with enhanced mechanical properties have attracted both fundamental and industrial interest. The present study concerns nanocomposites (NCs) made by dispersion of silica nanoparticles in a soft polymer matrix of styrene/butadiene (SB), which is commonly used in car tires. We work on both a simplified industrial system (solid mixing with millimetric silica pellets) and we developed a model system (solvent casting with surface-modified colloidal silica). The NC characteristics may be tuned by the grafting of silane coating agents (SCAs) which differ in the length of their alkyl groups (different hydrophobicity). These agents may influence filler dispersion via different polymer/filler and filler/filler interactions. The investigation of NC materials is essential for many industrial applications, in particular for the improvement of tire performances from an energetical and climatical point of view.
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Structure of chains and filler in nanocomposites: Impact of small beads and small molecules
Auteur(s): Genix A.-C.
(Séminaires)
Oak Ridge National Laboratory (ORNL) (Oak Ridge, US), 2017-09-08 |
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Structuring polymer gels via catalytic reactions
Auteur(s): Hugouvieux Virginie, Kob W.
(Article) Publié:
Soft Matter, vol. 13 p.8706-8716 (2017)
Texte intégral en Openaccess : 
Ref HAL: hal-01837825_v1
DOI: 10.1039/C7SM01814B
WoS: 000416556000005
Exporter : BibTex | endNote
2 Citations
Résumé: We use computer simulations to investigate how a catalytic reaction in a polymer sol can induce the formation of a polymer gel. To this aim we consider a solution of homopolymers in which freely-diffusing catalysts convert the originally repulsive A monomers into attractive B ones. We find that at low temperatures this reaction transforms the polymer solution into a physical gel that has a remarkably regular mesostructure in the form of a cluster phase, absent in the usual homopolymer gels obtained by a quench in temperature. We investigate how this microstructuring depends on catalyst concentration, temperature, and polymer density and show that the dynamics for its formation can be understood in a semi-quantitative manner using the interaction potentials between the particles as input. The structuring of the copolymers and the AB sequences resulting from the reactions can be discussed in the context of the phase behaviour of correlated random copolymers. The location of the spinodal line as found in our simulations is consistent with analytical predictions. Finally, we show that the observed structuring depends not only on the chemical distribution of the A and B monomers but also on the mode of formation of this distribution.
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