Biobased Pyrazine-Containing Polyesters

A set of 12 first-in-class, biobased pyrazine-containing polyesters was synthesized based on dimethylpyrazine dipropionic acid. These new diacid monomers were obtained from underutilized nitrogen-rich biomass. The polyester materials were synthesized via a two-step melt transesterification–polycondensation procedure with molecular weights between 12 300 and 47 500 g/mol and dispersities between 1.9 and 2.3. Six of the obtained polymers were amorphous and six were semi-crystalline. The thermal properties of the materials were studied; thermal degradation was found to take place at the monomer degradation temperature. The effect of methyl groups on the glass transition temperature was investigated, and the materials were found to behave mostly as aliphatic polyesters in this regard. The melting points of the methyl-substituted polyesters were found to be high and within the range of those of current high-performance polyesters. These materials are thus a welcome addition to current biobased polyesters.