Bio-Renewable Feedstock for Circular Polydiketoenamine Networks

Bio-synthesized plastics and durable goods thermosets are usually difficult to pair with circularity because of their various application fields, opposite lifetime and different chemistry. Here, we show that circular polydiketoenamines (PDK) vitrimers are produced with aromatic biorenewable monomer. Odd-even effects over different PDK spacer length are translated in a change of density and tensile modulus values. Chemical recycling is realized in a low intensive acid process with large monomer recovery variations through PDK series due to an increased degradation occurring in formulations featuring shorter spacers. While reaching high monomer recovery in powdered PDKs, PDK plastics with longer spacers enable higher monomer recoveries. Bioproduction of aromatic monomer is achieved from both glucose and glycerol in engineered <i>E. coli</i> using non-native thiolase BktB under fed-batch fermentation. System analysis scaling-up of the monomer production provides the estimated cost and greenhouse gas emission with different scenarios. Our results demonstrate the versatility of the circular PDK platform incorporating aromatic biorenewable synthons and potentially opening the way to chiral circular polymers.