The design of industrial products based on bioresources is a challenging issue. Modification of starch, by hydrophobic chemical substituents, results in an innovative hydrophobic material. Herein, the hydrophobic part of the derivative, comprised of octadienyl chains, is introduced through catalytic butadiene telomerization. The process is efficiently conducted on starch in its granular form in an aqueous medium using hydrosoluble palladium complexes. After optimization, a turnover number (TON) of up to 550 was achieved in the presence of [(pi-allyl)PdCl](2) catalyst and, unusually, by using dimethylisosorbide as a cosolvent.
Mesnager, Julien Quettier, Claude Lambin, Anne Rataboul, Franck Perrard, Alain Pinel, CatherineNowadays, the preparation of bio-based polymers remains a challenging issue. The modification of starch by hydrophobic chemical substitutions results in an innovative material. We introduced the hydrophobic part of the derivative via catalytic butadiene telomerization using exclusively water as solvent in the presence of surfactants. In this paper, we describe the influence of the nature of the surfactant on the reaction, CTAB (cetyltrimethylammonium bromide) giving the best reactivity. Moreover, some physicochemical properties of modified starches are evaluated showing their hydrophobic behaviours
Starch, an abundant and low-cost plant-based glucopolymer, has great potential to replace carbon-based polymers in various materials. In order to optimize its functional properties for bioplastics applications chemical groups need to be introduced on the free hydroxyl groups in a controlled manner, so an understanding of the resulting structure-properties relationships is therefore essential. The purpose of this work was to study the multiscale structure of highly-acetylated (degree of substitution, 0.4 < DS ≤ 3) and etherified starches by using an original combination of experimental strategies and methodologies. The molecular structure and substituents repartition were investigated by developing new sample preparation strategies for specific analysis including Asymmetrical Flow Field Flow Fractionation associated with Multiangle Laser Light Scattering, Nuclear Magnetic Resonance (NMR), Raman and Time of Flight Secondary Ion Mass spectroscopies. Molar mass decrease and specific ways of chain breakage due to modification were pointed out and are correlated to the amylose content. The amorphous structuration was revealed by solid-state NMR. This original broad analytical approach allowed for the first time a large characterization of highly-acetylated starches insoluble in aqueous solvents. This strategy, then applied to characterize etherified starches, opens the way to correlate the structure to the properties of such insoluble starch-based materials.
Mesnager, Julien Lambin, Anne Quettier, Claude Rataboul, Franck Pinel, CatherineThe synthesis of hydrophobic starch was performed via palladium-catalyzed telomerization of butadiene with native starch. This reaction is efficiently performed in water in the presence of neutral or cationic surfactant with high HLB. After optimization of the reaction conditions, TOF up to 446 was achieved
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