Rémi Auvergne

Reactivity of wheat gluten protein during mechanical mixing: radical and nucleophilic reactions for the addition of molecules on sulfur.

Mechanical properties of gluten-based biomaterials, such as break stress, were known to be influenced by temperature and shear stresses applied during processing. It is well documented in literature that these processing parameters promoted wheat gluten protein aggregation. Exchange between disulfide bonds and thiol groups oxidation are the postulated mechanisms that lead to gluten protein solubility loss in sodium dodecyl sulfate buffers. Both nucleophilic and radical reactions were postulated to act during gluten aggregation. To graft molecules on gluten, a study was carried out to explore the reactivity of its thiol and disulfide groups during thermomechanical mixing. A range of reactants able to react via radical or nucleophilic pathways with thiol groups were synthesized. Reactivity between gluten and functions was quantified by gluten solubility measurements. This investigation and literature observations allowed proposal of a general gluten aggregation mechanism during mixing.

Maleimides As a Building Block for the Synthesis of High Performance Polymers

ABSTRACT Maleimides are gaining a great deal of attention in both scientific and industrial communities since they can be used in high performance macromolecular systems: thermosets with high temperature stability, self-healing systems, or in click chemistry reactions. After an introduction, this review reports in the first part the different routes to synthesize maleimides. In the second part, this review focuses on the use of maleimides in polymer synthesis, first through nucleophilic reactions, second via cycloaddition to yield remendable systems, and then via radical polymerization. Finally, the industrial availability of maleimides is discussed.

Urea- and Thiourea-Catalyzed Aminolysis of Carbonates.

The aminolysis of (poly)carbonates by (poly)amines provides access to non-isocyanate polyurethanes (NIPUs) that are toxic-reagent-free analogues of polyurethanes (PUs). Owing to their low reactivity, the ring opening of cyclic carbonates requires the use of a catalyst. Herein, we report that the more available and cheaper ureas could advantageously be used for catalyzing the formation of NIPUs at the expense of the thiourea analogues. In addition, we demonstrate a medium-range pKa of the (thio)urea and an unqeual substitution pattern is critical for controlling the efficiency of the carbonate opening.