Rosin based epoxy coating: Synthesis, identification and characterization

Liquid crystalline epoxy crosslinker for enhanced performance. [Display omitted] •High-performance bio-based epoxy system from rosin acids.•High storage modulus and thermal stability epoxy coating for industrial applications.•Liquid crystal epoxy crosslinker. 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 1H 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).