3 research outputs found
Anionic polymerization of functional epoxide according to monomer activation
No full textLa synthèse de polyélectrolyte à base de polyéther a été peu étudiée, en particulier lorsque le polymère comporte des fonctions amine. Ces polymères offrent pourtant de larges perspectives dans le domaine des matériaux énergétiques ou celui des applications biomédicales. Dans l’objectif de contourner l’utilisation de l’épichlorhydrine, considérée comme toxique, le présent projet vise à revisiter la polymérisation de monomères contenant à la fois une fonction oxirane et une fonction amine protégée. La synthèse de ces monomères a d’abords été effectuée selon des réactions d’oxydation directe d’insaturation de monomères comportant une fonction amine protégée. Les oxiranes résultants ont été polymérisés par polymérisation anionique par ouverture de cycle selon le mécanisme du monomère activé. Les meilleurs résultats ont été obtenus pour le glycidylphtalimide ce qui a permis d’étendre les travaux à la synthèse de copolymères à blocs.Synthesis of polyether-based polyelectrolyte containing amine functions have scarcely been studied, while this polymer family offers a large set of potential applications in the biomedical domain and in material science for energetic application. With the aim of circumventing the use of the toxic epichlorhydrin, the present subject is revisiting the anionic ring opening polymerization of a set of monomers containing a protected amine and a polymerizable oxirane function. The syntheses of the monomers were first reported through the direct oxidation of unsaturated monomers containing ech a protected amine moities. Then these monomers were polymerized by anionic ring opening polymerization. The best results were achieved with glycidylphtalimide using an activated monomer mechanism. The homopolymers conditions synthesis were extended to the synthesis of block copolymers
Anionic ring-opening polymerization of N -glycidylphthalimide: Combination of phosphazene base and activated monomer mechanism
No full textInternational audienceAnionic ring‐opening polymerization of glycidyl phthalimide, initiated with alcohol–phosphazene base systems and based on monomer activation with a Lewis acid (iBu3Al), has been studied. No propagation occurred for initiator: iBu3Al ratios less or equal to 1:3. For larger Lewis acid amounts, the first anionic ring‐opening polymerizations of glycidyl phthalimide were observed. Polymers were carefully characterized by NMR, MALDI‐TOF mass spectrometry, and size exclusion chromatography and particular attention was given to the detection of eventual transfer or side‐reactions. However, polymer precipitation and transfer reaction to aluminum derivative were detrimental to monomer conversion, polymerization control, and limited polymer chain molar masses. The influence of reaction temperature and solvent on polymer precipitation and transfer reactions was studied and reaction conditions have been optimized leading to afford end‐capped poly(glycidyl phthalimide) with narrow molar mass distributions
Analysis of radionuclides in microsystem: application to the selective recovery of
No full textThe minimization of the sample quantities required by analytical laboratories, as well as the increase of the fastness of the analytical operations are emerging axes for improved radiochemical analyses related to D&D issues. Two microsystem-based protocols were developed for the selective recovery of 55Fe from radioactive samples by solvent extraction. Both protocols were tested on iron solutions in two different microchips. The yields of Fe extraction were compared with macroscale batch experiments. Better performances with more than 80% of iron extracted were obtained with the second protocol, which is based on a reactive transfer of the iron cation, and more suited to the use of microchannels and very low contact times. This study already demonstrate the high potential of microfluidic technology to improve analytical operations on D&D samples. This method will further be validated with radioactive samples
