Polycyanurate networks from dehydroanethole cyclotrimers: Synthesis and characterization

Novel biobased trisphenols were obtained by palladium- and cobalt-catalyzed [2 + 2 + 2] cycloaddition of dehydroanethole isomers which were readily prepared from the natural product trans-anethole. The trisphenols were transformed into their corresponding tricyanate esters and thermally cured to give polycyanurate networks. Comparison of the thermal properties, from differential scanning calorimetry, thermogravimetric and oscillatory thermomechanical analyses, of the new tricyanate esters with similar commercial products is presented. A new tricyanate ester with an acceptable processing temperature that yields a polycyanurate with very high glass transition temperature and low water absorption was found. Interestingly, the low moisture absorption was found to help limit the degradation of residual cyanate ester groups during exposure to hot water, allowing for a substantial recovery in the glass transition temperature upon subsequent heating, an unusual phenomenon for polycyanurate networks.