Guillaume Chollet

Activated lipidic cyclic carbonates for non-isocyanate polyurethane synthesis

Activated 5-membered cyclic carbonates were prepared from glycerol and fatty acid derivatives. Ester and ether moieties were introduced in the β position to the cyclic carbonate, in order to enhance its reactivity towards amines. 1H NMR kinetic investigation of the aminolysis of these cyclic carbonates demonstrated a higher reactivity compared to the one of alkyl substituted cyclic carbonates. In the case of ester-activated carbonates, a reactivity similar to the one of 6-membered ring cyclic carbonates was observed. Moreover, these carbonates exhibited amidation side-reactions with amines that could be however prevented by decreasing the temperature to room temperature. Poly(hydroxyurethane)s (PHUs) were then synthesized from these activated 5-membered ring cyclic carbonates at 70 °C in DMF (1 mol L−1) and exhibited molar masses up to 13700 g mol−1 with Tg in the range −26 to −10 °C.

Hydrophobe-free miniemulsion polymerization: towards high solid content of fatty acid-based poly(urethane-urea) latexes

Polyurethane-urea latex particles were synthesized by miniemulsion polyaddition of fatty acid-based diol derivatives and isophorone diisocyanate. The influence of the solid content, the surfactant and the hydrophobic agent was studied. Stable monodispersed latex particles with diameters around 200–300 nm were obtained with the solid content up to 50 wt%, without the use of any additional hydrophobic agent.

Synthesis and characterization of functionalized 4-O-methylglucuronoxylan derivatives

Abstract The purpose of this study was to design new biomaterials based on functionalized xylan derivatives. In one approach, 4-O-methylglucuronoxylan (MGX) of beechwood was oxidized by sodium periodate (NaIO4). A ratio of 0.2 NaIO4/xylose leads to a degree of oxidation of 0.15 with 75% yield. Then, the oxidized MGX aldehyde was submitted to reductive amination reaction with benzylamine, and as a result, the xylan backbone was effectively grafted with benzyl groups with a degree of substitution of 0.11. In another approach, controlled sulfuric acidic hydrolysis of MGX was performed to get well-defined xylooligosaccharides (XOS). Then, the reductive amination reaction of the XOS aldehyde functions was performed with allylamine or 2-aminoethylazide to graft the chain ends with an allyl or an azide function, respectively. The proposed methods can open a route to the design of new functional biomaterials.

Periodate oxidation of 4-O-methylglucuronoxylans: Influence of the reaction conditions.

This work aims at studying the sodium periodate oxidation of 4-O-methylglucuronoxylans (MGX) in different experimental conditions for a control of the oxidation degree. A series of sodium periodate oxidation reactions were conducted at three NaIO4/xylose molar ratios: 0.05, 0.20 and 1.00. The effects of xylan molar mass, xylan concentration and reaction temperature on the reaction rate have been evaluated by UV/visible spectroscopy at 0.20 NaIO4/xylose ratio. No depolymerization is observed at 0.05 ratio while depolymerization occurs at 0.20 and is even complete at 1.00 NaIO4/xylose ratio. An increase of the reaction temperature - up to 80 °C - leads to an increase of the oxidation rate with no effect on the depolymerization. At high xylan concentrations, the oxidation rate increases but promotes chains aggregation.