Biosourced vanillin Schiff base platform monomers as substitutes forDGEBAin thermoset epoxy

Diglycidyl ether Schiff base monomers were prepared from vanillin and various diamines. FT-IR,H-1 NMR,C-13 NMR, and mass spectroscopy were used to determine their structure. Cured thermoset epoxies made with them were compared to commercial epoxy in terms of mechanical properties. Tensile strengths ranged from 35.1 to 60.4 MPa, Young's modulus from 3.9 to 6.9 GPa, similar to the commercial product. The glass transition ranged from 80 to 117 degrees C, the phase transitionT(alpha)from 80 to 121 degrees C and the storage modulus from 2 to 3.5 GPa. Thermogravimetric analysis showed that the vanillin-based epoxies were less heat resistant but had higher residual mass (20-30% wt/wt). Hydrolysis, hydrophobicity and degradation were also monitored to evaluate their potential for coating applications.