ED Sciences Chimiques
Epoxy-anhydride precursors derived from abietic acid and vegetable oils for the design of aeronautical coatings with anticorrosive properties
by Marie KLEIN (Laboratoire de Chimie des Polymères Organiques)
The defense will take place at 9h30 - Amphithéâtre 1 Ecole Nationale Supérieure de Matériaux, d'Agroalimentaire et de Chimie, ENSMAC 16 Avenue Pey Berland, 33 600 Pessac
in front of the jury composed of
- Henri CRAMAIL - Professeur - Laboratoire de Chimie des Polymères Organiques/ Université de Bordeaux - Directeur de these
- Christelle DELAITE - Professeure - Laboratoire de Photochimie et d'Ingénierie Macromoléculaires - Université de Haute Alsace - Rapporteur
- Sylvain CAILLOL - Directeur de recherche - Institut Charles Gerhardt Montpellier - Rapporteur
- Alice MIJA - Professeure - Université Côte d'Azur - Examinateur
- Isabelle FABRE-FRANCKE - Docteure - Aéroprotec Services - Examinateur
This PhD work focuses on the synthesis of new biosourced epoxy-anhydride precursors derived from abietic acid and vegetable oils, for the development of anticorrosive coatings for aeronautic pieces. They are part of an initiative to decarbonize the aerospace industry and replace raw materials targeted by the European REACH regulation (e.g. Bisphenol A, Chromium). The studied precursors are multifunctional molecules, bearing both epoxy and anhydride functions to obtain thermosetting materials. Their synthesis is based on the coupling of abietic acid with an unsaturated fatty amine via an amidation reaction. An anhydride function is then introduced onto the abietic tricycle by a Diels-Alder reaction with maleic anhydride, followed by the epoxidation of the fatty chain's unsaturation using a peracid. The resulting epoxy-anhydride precursors are stable at room temperature and their self-polymerisation can be initiated at high temperatures (T > 140°C) in the presence of catalytic amounts of tertiary amines. Their crosslinking reaction with commercial polyepoxy co-reagents, derived from glycerol, vanilline or vegetable oils (soja, cardanol), resulted in a series of new thermosetting materials, whose thermo-mechanical properties were evaluated. Finally, these formulations were used to coat aluminium alloy plates in order to assess their anticorrosive properties under salt spray exposure, and consequently their potential as protective coatings for metallic parts. Some of them proved to be highly efficient over timeframes compliant with aeronautic standards, paving the way for the replacement of current pre-treatments with more sustainable and environmentally friendly solutions.