Rosin based epoxy coating: Synthesis, identification and characterization

Ketone type derivative of rosin was prepared by dehydrocarboxylation of isomerized abietic acid. Coupling of dipimaryl ketone with maleic anhydride was performed by acetic acid catalyzed Diels-Alder reaction. Afterwards, the dipimaryl ketone was epoxidized to get the corresponding tetra glycidyl ester. The chemical structure of the synthesized products was confirmed by UV, FTIR and H-1 NMR spectroscopic analyses. Cured resins using a rosin-based crosslinker and p-phenylene diamine (a commercial crosslinker) were evaluated using dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA) and some preliminary universal coating tests. Results showed that the fully rosin-based epoxy system gave better performance than commercially bisphenol-A based one. This finding was attributed to a liquid crystal behavior of the rosin-based crosslinker. Mesomorphic transition temperature and liquid crystalline texture of the rosin-based crosslinker were investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). (C) 2015 Elsevier Ltd. All rights reserved.