Green Approach of Photoinitiated Polymerization Using Monomers Derived from Oleic Acid and Ionic Liquid

Bio-based monomers synthesized from oleic acid mix and nonvolatile ionic liquid monomers were investigated by photo-DSC using 2,4,6-trimethylbenzoylphenyl phosphinate (Irgacure (R) TPO-L) or dibenzoyldiethylgermane (Ivocerin (R)) as photoinitiator. The results were compared with those obtained for commercial hexanediol-1,6-di(meth)acrylate. The ionic liquid monomers (N-octyl-N'-vinylimidazolium bis(trifluoromethylsulfonyl)imide (NTf2) and N-decyl-N'-vinylimidazolium NTf2) showed lower reactivity compared to the diacrylate and slightly higher reactivity than the methacrylates. The vinyl group bound at the imidazolium ring fully converted during photoinitiated polymerization as confirmed by H-1 NMR analysis. Final conversion was higher for the imidazole-functionalized methacrylate derived from fatty acid compared to both the hydroxy-functionalized derivative and hexandiol-1,6-dimethacrylate although the maximum of the polymerization rate was lower for the bio-based monomers indicating their lower reactivity.