Aromatic and semi-aromatic polyesters are valuable commodity plastics. Accounting for roughly 10% of the global plastic economy, they boast easy processability and robust thermal and mechanical properties.1,2 However, aromatic monomers used for the synthesis of these polyesters are derived almost exclusively from petroleum feedstocks.3,4 While many aliphatic polyesters derived from biosources have seen commercial success in recent years, examples of biobased aromatic monomers are less common. 5,6 In terms of bioaromatic monomers, lignin is a promising feedstock.7–9 Various depolymerization processes can be applied to generate hydroxycinnamic acids, hydroxybenzoic acids, benzaldehydes, styrenics, and other useful platform chemicals from lignin biomass.8–13 In our work we have synthesized a series of polyesters based on hydroxycinnamic acids. Using biobased cyclic carbonates, alkylation of the phenolic group affords monomers with potentially 100% biobased carbons. Polymerization yielded both semi-crystalline and amorphous polyesters with mechanical properties varying over six orders of magnitude. Simple variation of methoxy substitution and alkyl groups allows for a wide array of properties. The polyesters synthesized include a highly ductile thermoplastic, a strong and rigid thermoplastic, and an elastomer. Composting biodegradation tests showed both degradable and nondegradable polymers can be achieved in this class. The versatility of this class of polyesters illustrates their potential to replace non-sustainably derived plastics.
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(12) Takeshima, H.; Satoh, K.; Kamigaito, M. Bio-Based Functional Styrene Monomers Derived from Naturally Occurring Ferulic Acid for Poly(Vinylcatechol) and Poly(Vinylguaiacol) via Controlled Radical Polymerization. Macromolecules 2017, 50 (11), 4206–4216.
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