Papers by Virginie Boucher
Chemical Communications, 2012
Composites termoestables reciclables derivados de textiles de desecho
The idea of recycling waste materials from such different sectors as textile or automotive has... more The idea of recycling waste materials from such different sectors as textile or automotive has been popular for decades, but today's recycling methods often produce poor quality products that are difficult to reuse. In the specific case of thermoset composites the problem is even greater, since once the resin is cured its dissolution is not possible and therefore the recovery of the original fiber and resin becomes practically unfeasible. This work presents recyclable thermoset composites made with fabrics obtained from waste textiles and epoxy or polyurethane resins, whose crosslinking is based on reversible bonds, which confers them the ability to be dissolved in a specific agent, so that both the fiber and the resin can be recovered for subsequent reuse. Taking into account the particularities of the starting raw materials, the manufacturing parameters of the composites and the resin dissolution conditions have been studied and optimized. The work is part of the European p...
Remerciements L'ensemble des travaux présentés dans ce mémoire a été réalisé dans le laboratoire ... more Remerciements L'ensemble des travaux présentés dans ce mémoire a été réalisé dans le laboratoire LSPES (UMR
Polymer thin films as a route to access low energy glassy states
Resumen del trabajo presentado al APS March Meeting, celebrado en Baltimore, Maryland (USA) del 1... more Resumen del trabajo presentado al APS March Meeting, celebrado en Baltimore, Maryland (USA) del 14 al 18 de marzo de 2016.
Physical Chemistry Chemical Physics, 2017
By aging, we draw glassy polymer films to a thermodynamic state, the ideal glass, with the entrop... more By aging, we draw glassy polymer films to a thermodynamic state, the ideal glass, with the entropy of the crystal.
Preparation of polycarbonate transparent nanocomposites : structure/properties relationships
L'objet de cette étude est l'élaboration de matériaux polymères nanocomposites transparen... more L'objet de cette étude est l'élaboration de matériaux polymères nanocomposites transparents à matrice polycarbonate, pour des applications dans des domaines tels que la lunetterie ou le vitrage automobile. L'incorporation de nanoparticules au sein du polycarbonate a été envisagée afin de lui conférer certaines propriétés mécaniques telles qu'une plus grande rigidité, une meilleure stabilité dimensionnelle, une résistance à la rayure plus importante, tout en conservant sa transparence. Le maintien de la transparence du matériau passe d'une part par l'utilisation de particules nanométriques présentant un indice de réfraction proche de celui de la matrice et d'autre part par une trés bonne dispersion de ces particules au sein de la matrice polymère. Ainsi différents types de nanoparticules minérales ont d'abord été sélectionnés puis incorporés dans la matrice polycarbonate. L'évaluation des performances de ces nanocomposites en termes de transparence...
The Journal of Chemical Physics, 2017
We investigate the kinetics of enthalpy recovery in stacked glassy polystyrene (PS) films with th... more We investigate the kinetics of enthalpy recovery in stacked glassy polystyrene (PS) films with thickness from 30 to 95 nm over a wide temperature range below the glass transition temperature (T g). We show that the time evolution toward equilibrium exhibits two mechanisms of recovery, in ways analogous to bulk PS. The fast mechanism, allowing partial enthalpy recovery toward equilibrium, displays Arrhenius temperature dependence with low activation energy, whereas the slow mechanism follows pronounced super-Arrhenius temperature dependence. In comparison to bulk PS, the time scales of the two mechanisms of recovery are considerably shorter and decreasing with the film thickness. Scaling of the equilibration times at various thicknesses indicates that the fast mechanism of recovery is compatible with the free volume holes diffusion model. Conversely, the slow mechanism of recovery appears to be accelerated with decreasing thickness more than predicted by the model and, therefore, its description requires additional ingredients. The implications, from both a fundamental and technological viewpoint, of the ability of thin polymer films to densify in relatively short time scales are discussed.
Remerciements L'ensemble des travaux présentés dans ce mémoire a été réalisé dans le laboratoire ... more Remerciements L'ensemble des travaux présentés dans ce mémoire a été réalisé dans le laboratoire LSPES (UMR
Effect of silica particles concentration on the physical aging of PMMA∕silica nanocomposites
AIP Conference Proceedings, 2010
We have monitored the physical aging of poly (methyl methacrylate)(PMMA)∕ silica nanocomposites, ... more We have monitored the physical aging of poly (methyl methacrylate)(PMMA)∕ silica nanocomposites, namely the slow evolution occurring to the structure of glasses below the glass transition temperature (Tg), following the time evolution of the enthalpy as measured by differential scanning calorimetry (DSC). We have systematically varied the concentration of silica to provide insight about the influence of the ratio area of silica∕ volume of PMMA on the physical aging process. Our results clearly indicate that physical aging speeds up with ...
Soft Matter, 2012
Linear polystyrene (PS) from Polymer Source Inc. with the following molecular weights was employe... more Linear polystyrene (PS) from Polymer Source Inc. with the following molecular weights was employed: M w = 1408 kg/mol, M w /M n =1.17 and M w = 572 kg/mol, M w /M n =1.1. Toluene (99.8 %; Sigma-Aldrich) was used to dissolve PS. Freestanding PS films with thicknesses h ≥ 1µm were prepared by solvent casting PS solutions into freshly cleaned Petri dishes of varying sizes (Duran Group), placed on a horizontal bench under the fume hood. After casting of the PS solution, the samples were left at room temperature under the fume hood during at least 12 hrs before being transferred to an oil free vacuum oven at 433 K, where they were dried during 4 days. After annealing, the solvent casted films were removed from the Petri dishes by the floating on water method. The thickness of the so-prepared samples was verified by Scanning Electron Microscopy (SEM). Freestanding PS films with thicknesses h < 1µm were prepared by spin coating PS solutions onto ultraflat glass slips (18x24 mm; Menzel-Gläser), previously rinsed in acetone. Spin-coating was realized with a speed of 50 rpm, during 30 s, under the fume hood. The thickness of the films was controlled by varying polymer concentration. As-deposited PS films were annealed in vacuum at 433 K for 4 days in oil free oven to remove the solvent and the stress induced by spin coating. 1 The thickness of the so-prepared samples was checked by Atomic Force Microscopy (AFM), which also revealed no inhomogeneities at the surface of the films. After annealing, the dried thin films were removed from the glass substrates by floating on water. In all cases the thickness was determined with a precision of 10 %, on the base of measurements performed on several samples for each thickness.
Physical aging of polystyrene/gold nanocomposites and its relation to the calorimetric Tg depression
Soft Matter, 2011
The aim of this work is to study the effect of gold nanoparticles on the segmental dynamics, glas... more The aim of this work is to study the effect of gold nanoparticles on the segmental dynamics, glass transition (Tg) and physical aging of polystyrene (PS). To do so, PS/gold nanocomposite samples containing 5 and 15 wt% of 60 nm spherical gold nanoparticles, surface-treated with thiolated-PS, were prepared. The segmental dynamics of PS, as measured by means of broadband dielectric spectroscopy (BDS), was found to be unchanged in the presence of gold nanoparticles. Conversely, the calorimetric Tg of PS ...
Physical aging in polymers and polymer nanocomposites: recent results and open questions
Soft Matter, 2013
Uploads
Papers by Virginie Boucher