Bio-based monomers for UV-curable coatings: allylation of ferulic acid and investigation of photocured thiol-ene network

Y Ferulic acid (FA) is an unsaturated hydroxycinnamic acid that can be isolated from lignin. In this study, the biorenewable FA was allylated to result in a library of monoor diallylated monomers, either having the inherent cinnamoyl double bond intact or saturated through hydrogenolysis. All monomers were photo-chemically cured with trimethylolpropane tris(3-mercaptopropionate) (TRIS) into crosslinked films in the presence of a photo initiator (Irgacue 819). The reactivity of the FA-derived monomers toward TRIS was investigated in detail by photorheology and FT-IR spectroscopy to reveal details on the relative reaction rates for the different alkene groups. The thermo-mechanical properties of the crosslinked films were fully characterized by means of dynamic mechanical analysis (DMTA) and thermal calorimetry (DSC). It was demonstrated that the glass transition temperature of the final crosslinked network could be controlled by the addition of a monoallylated monomer. By increasing the content of the monoallylated compound, it was possible to observe a linear decrease of the Tgvalues of the crosslinked films.

Automated summary

In this study, biorenewable FA was allylated to produce a library of mono or diallylated monomers, which were then photo-chemically cured with TRIS to form crosslinked films. The reactivity of the monomers towards TRIS was investigated, revealing that the addition of monoallylated monomer could control the glass transition temperature of the final crosslinked network.