Évènements

02 Jun
02/06/2017 10:00

Research

Soutenance de thèse : Clarice FEDOSSE ZORNIO

Ionic liquids as multifuncional additives for poly (methyl methacrylate)-based materials

Doctorante : Clarice FEDOSSE ZORNIO 

Laboratoire INSA : IMP
Ecole doctorale : EDA034 : Matériaux de Lyon

The large array of cation/anion combinations, and the excellent intrinsic properties of ionic liquids (ILs) open a large range of possibilities in their use as additives to polymer materials. Thus, the main objective of this work is to explore the role of both the cation and anion of a series of ILs on the properties of poly(methyl methacrylate) (PMMA) -based materials. In a first approach, low amounts of imidazolium and ammonium-based ILs were incorporated as additives to PMMA in the melt state. Morphological and structural characterizations were developed in order to understand their impact on the thermal, viscoelastic, and mechanical properties of the resulting materials. Then, in the following section, the ability of the same imidazolium and ammonium-based ILs as physical modifiers of silica surface was evaluated. Sub-micron and nanosize silica particles were used to prepare PMMA composites. In such an approach, ILs were supposed to act as interfacial agents. Thus, the extent of each IL to improve the interfacial interaction between PMMA and silica particles was discussed. In addition, supercritical carbon dioxide (scCO2) was used as foaming agent to produce foamed PMMA composite materials. In such a case, the combined effect of the presence of ILs and silica particles was analyzed regarding the morphology of the foamed structures. In the last section, scCO2 was used as reaction medium, in an environmental friendly approach, to chemically modify silica nanoparticles using a series of imidazolium IL-functionalized silanes (with different alkyl chain lengths). Thermogravimetric analysis (TGA) was used to highlight the effect of the working pressure and the content of such ILs in the reaction medium. The effect of the alkyl chain length on the grafting density of the modified nanoparticles was also discussed. Finally, novel PMMA-based nanocomposites were prepared by the incorporation of such modified nanoparticles. TEM and SANS analyses were used to evaluate the state of dispersion of the particles into the polymer matrix, and the thermal, rheological and mechanical properties of the samples were studied.