Dispersions Aqueuses de Polymères bio-sourcés

Waterborne bio-sourced polymers

• Auteur / Autrice : Boris Bizet
• Direction : Henri Cramail
• Type : Projet de thèse
• Discipline(s) : Polymères
• Date : Inscription en doctorat le 01/04/2016
• Etablissement(s) : Bordeaux en cotutelle avec Université du Pays basque à Bilbao, Vitoria-Gasteiz et Saint-Sébastien
• Ecole(s) doctorale(s) : Sciences Chimiques
• Partenaire(s) de recherche : Laboratoire : Laboratoire de Chimie des Polymères Organiques
• Partenaire(s) de recherche : Equipe de recherche : EQ2 - Biopolymères et Bio-Sourcés Polymères

Mots clés

Mots clés libres

Polyuréthane

Polyacrylique

Dispersion aqueuse

Polymérisation en émulsion

Polymères Bio-sourcés

Polyurethane

Polyacrylic

Waterborne

Emulsion polymerization

Bio-sourced Polymers

Résumé

The first part of the project will be performed at the University of Bordeaux and will be devoted to the synthesis of the functional monomers and polymers. The objective is to develop original and environmentally friendly synthetic routes to bio-sourced polyurethanes and polyepoxides, using fatty acid methyl esters and vegetable oils as well as CO2 as starting renewable raw materials. This proposal relies on three pillars which are the use of i) available precursors from vegetable oils, ii) CO2 as a reactant avoiding the use of carcinogenic intermediates and iii) organocatalysts such as ionic liquids or carbenes as substitutes of metal-based catalysts. Functional monomers issued from bio-resources with be first synthesized and purified. Then, polymerization will be investigated in bulk and also in aqueous dispersion, paying particular attention to the compatibility of the system with water emulsion polymerization in terms of monomers/catalyst water stability, temperature of polymerization… Polymerization kinetics and its linked with monomers structures and catalysts will be investigated next. Finally, the physico-chemical and thermo-mechanical properties of the polymers will be evaluated. The monomers demonstrating both good compatibility with emulsion technique and leading to polymers of interest will be then fully developed and investigated in the team of Prof Asua for latexes synthesis. The second part of the work will be carried out at the University of the Basque Country and will be devoted to the polymerization of these monomers in aqueous dispersed media. The particular process to be used will depend on the hydrophilicity of the functional monomers. In principle, two alternatives are considered: emulsion polymerization for sufficiently hydrophilic monomers and miniemulsion polymerization for hydrophobic monomers and prepolymers. Considering the bio-based raw materials, this second alternative seems more likely. The materials that are aimed in this project are “products-by-process” and hence their characteristics are attained in the reactor, namely, they depend on the way in which the process is conducted. The controlled synthesis of these materials requires i) to form the miniemulsion of composite droplets of controlled size and composition, making them colloidally stable and stable with respect Oswald ripening, ii) to polymerize most of these droplets avoiding both other nucleation mechanisms and coagulation with particles and droplets, iii) to achieve high conversion minimizing the residual monomer, and iv) to control polymer architecture (composition, MWD, branching, gel, …). Miniemulsification is the bottle-neck of the industrialization of miniemulsion polymerization and hence the development of an efficient and robust miniemulsification process will be the first objective of the part of the research. Both high pressure homogenization and sonication will be used and the effect of the type and concentration of surfactant will be investigated. It is worth pointing out that the amount of surfactant should be minimized to reduce water sensitivity of the final products. Then, polymerization will be studied paying particular attention to maximizing droplet nucleation and avoiding both secondary nucleation and coagulation. Polymerization kinetics and its influence on polymer properties will be investigated next. Finally, the application properties of the coatings (minimum film forming temperature, mechanical properties, scrub resistance, water uptake, water and vapor transmission, transparency and gloss) will be studied.