AUTHOR=Diot-Néant Florian , Migeot Loïs , Hollande Louis , Reano Felix A. , Domenek Sandra , Allais Florent 

TITLE=Biocatalytic Synthesis and Polymerization via ROMP of New Biobased Phenolic Monomers: A Greener Process toward Sustainable Antioxidant Polymers

JOURNAL=Frontiers in Chemistry

VOLUME=5

YEAR=2017

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2017.00126

DOI=10.3389/fchem.2017.00126

ISSN=2296-2646

ABSTRACT=<p>Antioxidant norbornene-based monomers bearing biobased sterically hindered phenols (SHP)—<bold>NDF</bold> (norbornene dihydroferulate) and <bold>NDS</bold> (norbornene dihydrosinapate)—have been successfully prepared through biocatalysis from naturally occurring ferulic and sinapic acids, respectively, in presence of <italic>Candida antarctica Lipase B</italic> (Cal-B). The ring opening metathesis polymerization (ROMP) of these monomers was investigated according to ruthenium catalyst type (GI) vs. (HGII) and monomer to catalyst molar ratio ([M]/[C]). The co-polymerization of antioxidant functionalized monomer (<bold>NDF</bold> or <bold>NDS</bold>) and non-active norbornene (<bold>N</bold>) has also been performed in order to adjust the number of SHP groups present per weight unit and tune the antioxidant activity of the copolymers. The polydispersity of the resulting copolymers was readily improved by a simple acetone wash to provide antioxidant polymers with well-defined structures. After hydrogenation with <italic>p</italic>-toluenesulfonylhydrazine (<italic>p</italic>-TSH), the radical scavenging ability of the resulting saturated polymers was evaluated using α,α-diphenyl-β-picrylhydrazyl (DPPH) analysis. Results demonstrated that polymers bearing sinapic acid SHP exhibited higher antiradical activity than the polymer bearing ferulic acid SHP. In addition it was also shown that only a small SHP content was needed in the copolymers to exhibit a potent antioxidant activity.</p>