Fatty acid-based cross-linkable polymethacrylate coatings

In this paper, novel epoxy prepolymers from oleic acid-based monomers were cross-linked to prepare thermosets for coating application. For this purpose, methacrylate moiety was firstly added to oleic acid via Steglich esterification prior to conventional radical polymerization. The resulting oleic acid-based polymer was obtained with a number molecular weight 40,000 g/mol (DP = 110). Then the internal unsaturations of this polymer were epoxidized at different epoxy contents to provide cross-linkable functionalities. Based on a study of the internal epoxy reactivity of a model compound with different nucleophiles, the synthesized oleic-based polymers with epoxy functions hanging off the main chain were successfully cross-linked with succinic anhydride. Dynamic mechanical and thermal analyses, as well as swelling index properties have been studied for all the resulting thermosets. Additionally, the properties of coatings on steel substrates were studied to determine coating hardness, and adhesion. The results of this work provide evidence of the potential of these materials as bio-based coatings and adhesives.