Biobased UV-curable coatings based on itaconic acid

A series of renewable unsaturated polyesters were synthesized from itaconic acid (IA), succinic acid, and 1,4-butanediol by solvent-free polycondensation. Previous studies utilizing IA to make polyesters for coating applications have shown great potential; however, the curing and material properties have not been investigated in detail. The aim of this study was to investigate how the curing is affected by the amount of unsaturations and how well itaconate-based polyesters crosslink without the addition of any other unsaturated monomers or reactive diluents. The chemical structures of the polyesters were confirmed with FTIR, 1 HNMR, and THF-SEC. The degree of curing was studied with FTIR, and the mechanical properties of the crosslinked polyesters were evaluated with DMA, pendulum hardness, and microindentation. The degree of curing was found to be up to 75%, and furthermore, it was found that the final mechanical properties of the crosslinked coatings could be tuned by modifying the IA content in the monomer composition. The results from DMA showed that there is a clear trend between mechanical properties and crosslinking density.