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® TPOÀ L) or dibenzoyldiethylgermane (Ivocerin®) 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 (NTf 2 ) and N-decyl-N'-vinylimidazolium NTf 2 ) 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 1 H NMR analysis. Final conversion was higher for the imidazole-functionalized methacrylate derived from fatty acid compared to both the hydroxyfunctionalized derivative and hexandiol-1,6-dimethacrylate although the maximum of the polymerization rate was lower for the bio-based monomers indicating their lower reactivity.

A new bio‐based dimethacrylate (EMHO) consisting of three isomers, that is (ethane‐1,2‐diyl‐bis(9‐methacryloyloxy‐10‐hydroxy octadecanoate) [EMHO‐i1], ethane‐1,2‐diyl‐9‐hydroxy‐10‐methacryloyloxy‐9′‐methacryloyloxy‐10′‐hydroxy octadecanoate [EMHO‐i2], and ethane‐1,2‐diyl‐bis(9‐hydroxy‐10‐methacryloyloxy octadecanoate [EMHO‐i3]), was made by a three‐step reaction starting from esterification of oleic acid with ethylene glycol followed by epoxidation in a second step, and epoxy ring‐opening reaction with methacrylic acid in a third step. The new dimethacrylate obtained was photocured applying ultra‐violet technology to receive a neat polymer on the one hand and in the presence of a further methacrylate, such as 4‐(4‐methacryloyloxyphenyl)‐butan‐2‐one (MAPO) or methyl 9‐(1H‐imidazol‐1‐yl)‐10‐(methacryloyloxy)‐octadecanoate and methyl 9‐(methacryloyloxy)‐10‐(1H‐imidazol‐1‐yl)‐octadecenoate available as isomer mixture (MIMAO), on the other hand. The photopolymerization kinetic study applying photo‐differential scanning calorimetry technology showed that the addition of MAPO or MIMAO during photocuring resulted in an increase in both polymerization rate and final conversion on monomer in comparison with the homopolymerization of EMHO. As expected, the network density obtained by the study of the elastic modulus of the copolymers was reduced compared to the homopolymer caused by the presence of the methacrylate MAPO or MIMAO comprising only one polymerizable functional group. The crosslinked polymer films contain high gel content. Those films made by using an excess of MAPO showed a glass transition above room temperature caused by the aromatic ring comprising in MAPO. High contact angle values for water indicate the high hydrophobicity of the crosslinked polymer films that is attributed to the long alkyl chains contained in the bio‐based dimethacrylate. The copolymer made from the bio‐based dimethacrylate with MAPO excess may be interesting for application as a water‐repellent coating for surface protection and protection against corrosion.

No abstract

Investigation of photopolymerization kinetics of 4-(4-methacryloyloxyphenyl)butan-2-one (1) in comparison with 2-phenoxyethyl methacrylate (2) and phenyl methacrylate (3) using a UV-LED emitting at 395 nm shows significantly faster polymerization of 1 compared to both 2 and 3 at 40 C. Vitrification affects photopolymerization kinetics of all methacrylates under investigation.

No abstract