Bio-based materials from Cardanol/cardol with episulfide group (CCES) and epoxy group (CCEO) were synthesized and further blended with commercial bisphenol-A diglycidyl ether type epoxy resin (DGEBA) for anti-corrosion coating application. The curing behavior of CCEO and CCES confirmed that episulfide exhibited a faster curing rate and higher curing conversion than epoxide. Anticorrosion properties of composite system CCEO/CCES and DGEBA were also carried out. Equilibrium water content of CCES-DGEBA blend was much lower than neat DGEBA and CCEO-DGEBA composite system in water absorption test, which met agreement with that CCES-DGEBA blend system revealed better adhesive to the metal compared with DGEBA and CCEO-DGEBA blend in lap sheer strength assessment. Further, CCES-DGEBA blend with 20 wt% of CCES exhibited optimized performance in corrosion resistance as it possessed the higher impedance modulus at low frequencies in EIS bode plots, lowest corrosion current and the highest corrosion voltage in Tafel test.
Available online 17 June 2017