Catalytic decarbonylation of biosourced substrates.

Linear α-olefins (LAO) are one of the main targets in the field of surfactants, lubricants, and polymers. With the depletion of petroleum resources, the production of LAO from renewable feedstocks has gained increasing interest in recent years. In the present study, we demonstrated that Ir catalysts were suitable to decarbonylate a wide range of biosourced substrates under rather mild conditions (160 °C, 5 h reaction time) in the presence of potassium iodide and acetic anhydride. The resulting LAO were obtained with good conversion and selectivity provided that the purity of the substrate, the nature of the ligand, and the amounts of the additives were controlled accurately. The catalytic system could be recovered efficiently by using a Kugelrohr distillation apparatus and recycled.

Bio-based aliphatic polyurethanes through ADMET polymerization in bulk and green solvent.

A new route to α,ω-diene urethane monomer is proposed by converting 10-undecenoic acid into the corresponding acyl azide, followed by urethanization with 10-undecenol. ADMET polymerizations of this α,ω-diene urethane monomer as well as other bio-based α,ω-dienes bearing various organic functions (ester, carbonate, ether, amide) were carried out in bulk and solution conditions. A screening of the most commonly used metathesis catalysts allows to evaluate their tolerance toward the urethane function as well as toward Polarclean, a "green" and nontoxic high boiling point solvent. The influence of the nature of the central organic function in these α,ω-diene monomers on the thermomechanical properties is investigated.

Impact of RGD nanopatterns grafted onto titanium on osteoblastic cell adhesion.

This work reports on the synthesis of titanium bone implants functionalized with nanoparticles (NPs) containing Arg-Gly-Asp-Cys peptide (RGDC) and shows the adhesion behavior of cells seeded on these materials. RGDC peptides were first conjugated to a norbornenyl-poly(ethylene oxide) macromonomer (Nb-PEO). Then, functional NPs with a size of ∼300 nm and constituted of polynorbornene core surrounded by poly(ethylene oxide) shell were prepared by ring-opening metathesis polymerization in dispersed medium. The grafting density of these NPs on the titanium surface is up to 2 NPs·µm(-2) (80 pmol of RGDC per cm(-2) of NP surface). Cell adhesion was evaluated using preosteoblast cells (MC3T3-E1). Results of cells cultured for 24 h showed that materials grafted with NPs functionalized with RGDC peptides enhance specific cell adhesion and can create filopodia-like structures among NP sites by stressing the cells.