Vincent Besse

Vanillin, a promising biobased building-block for monomer synthesis

Vanillin was used as a renewable building-block to develop a platform of 22 biobased compounds for polymer chemistry. Vanillin-derived biobased monomers bearing epoxy, cyclic carbonates, allyl, amine, alcohol and carboxylic acid moieties were synthesized. They can be used, among many others, in epoxy, polyester, polyurethanes, and Non-Isocyanate PolyUrethanes (NIPU) polymer synthesis. The epoxy-functionalized compounds were synthesized under solvent-free conditions and are original biobased aromatic epoxy monomers. Cyclic carbonates were prepared through a catalytic reaction between epoxy compounds and CO2. Thiol–ene reactions allowed the functionalization of allylated compounds with amines, acids and alcohols. The amine-functionalized compounds are, to our knowledge, the first non-aliphatic biobased amine hardeners, usable either in epoxy or NIPU materials.

Photopolymerization study and adhesive properties of self-etch adhesives containing bis(acyl)phosphine oxide initiator

OBJECTIVE This paper investigates the photo-co-polymerization behavior of a blend of a diacrylamide (DEBAAP) with a phosphonylated acidic monomer using either bis(acyl)phosphine oxide or camphorquinone/amine as photo-initiator and studies the effect of variation of the structure of the phosphonylated acidic monomer on the shear bond strength to human dentin. METHODS Photopolymerization kinetics has been assessed through the use of photo-DSC with either initiating system and with and without a phosphonic acid monomer, while the shear bond strengths (SBS) of dentin bonding agents formulated with several phosphonylated acidic monomers have been evaluated by macro SBS testing on human dentin. RESULTS Photo-DSC results show that bis(acyl)phosphine oxide initiates a faster polymerization than camphorquinone/amine and that both photopolymerizations are accelerated by the phosphonic acid monomer. Similar results were obtained between adhesives based on camphorquinone/amine and a commercial adhesive (AdheSE, Ivoclar-Vivadent, Schaan, Liechtenstein). The best performances were obtained when BAPO was used as the initiator, in many cases far better than the commercial adhesive. Adhesive SEA6 based on difluoromethylphosphonic acid C demonstrated the best adhesion results of this study. Significance The bis(acyl)phosphine oxide photo-initiator causes faster photopolymerization of two-step self-etching dental adhesive, and its use could yield better bonding performance.