Post-Modification of Biobased Pyrazines and Their Polyesters

Monomers and polymers from biobased pyrazine underwent post-modification reactions to synthesize a series of novel tailored polyesters with a tunable structure and adjustable physico-chemical properties. Modification by alkylation had limited success. However, controlled oxidative post-modification is possible, without loss of molecular weight. The degree of oxidation has a large effect on the thermal properties of the polyesters. One of the polyesters shows loss of crystallinity combined with an increase in the glass-transition temperature at increasing degrees of oxidation. For the other polyester, oxidation results in an elevated melting point. Weak hydrogen bonds are responsible for the latter observation as demonstrated by infrared spectroscopy. The surface modification of a polymer film results in different wetting behaviors. Our biobased pyrazine building blocks and their ability to be post-modified offer interesting opportunities in added functionality materials of the future.