Readily Degradable Aromatic Polyesters from Salicylic Acid

Abstract

Polyesters constitute around 10% of the global plastic market with aromatic polyesters, such as poly(ethylene terephthalate) (PET), being the most prevalent because of their attractive properties. As for most commercial plastics, polyesters are primarily derived from fossil resources and are not readily degradable, which raises a number of sustainability concerns. Designing polymers with competitive properties from sustainable feedstocks that rapidly degrade under mild conditions is an attractive strategy for addressing the current plastic waste problem. Here, the detailed synthesis and characterization of degradable, high molar mass aromatic polyesters derived from salicylic acid, poly(salicylic glycolide) (PSG), and poly(salicylic methyl glycolide) (PSMG) are described. The synthesis of polymers was investigated through mechanistic experiments and complementary computational studies. The glass transition temperature (T g ≈ 85 °C) and Young's modulus (E ≈ 2.3 GPa) of these polyesters are comparable to those of PET. In contrast to the poor hydrolytic degradability of PET, both PSG and PSMG are readily degradable in neutral aqueous solutions (e.g., complete degradation in seawater at 50 °C in 60 days). These aromatic polyesters derived from salicylic acid have potential as future high-performance, sustainable, and degradable plastics.

Bioderived and degradable polymers for transient electronics

“…Ellison and coworkers reported molar masses of 10 and 22 kg·mol −1 polymers for PSG and PSMG, respectively. The polymers displayed moderate thermal stability (T d ≈ 265 °C) and high elasticity (E ≈ 2.3 GPa), with the latter being comparable to commercial PET (E ≈ 1.7–2.7 GPa) 21 . Furthermore, both polymers degraded in seawater at 50 °C in 60 days, exhibiting faster degradation under milder conditions in comparison to PLA and PET.…”

Integrating Emerging Polymer Chemistries for the Advancement of Recyclable, Biodegradable, and Biocompatible Electronics

“…Recently, Hillmyer, Ellison, and coworkers also synthesized biodegradable polyesters from sustainable feedstocks that rapidly degrade under mild conditions (Figure 4b ). [ 38 ] Aromatic polyesters derived from salicylic acid, poly(salicylic glycolide) (PSG) and poly(salicylic methyl glycolide) (PSMG), were found to have comparable glass transition temperatures and Young's moduli to those of PET. PSG and PSMG were immersed in PBS solution (pH 7.4), artificial seawater (pH = 8.0), DI water (pH = 7.1) and 0.1 m NaOH at 50 °C.…”

Sequence‐Controlled Alternating Copolyesters Synthesis via Selective Ring‐Opening Polymerization

“…Ellison et al described the synthesis of poly(salicylic methyl glycolide) (PSMG) and poly(salicylic glycolide) (PSG) in 2020 (Figure 4). [31] The two bio-based monomers, both SG and SMG were synthesized by a two-step reaction with salicylic acid (phenol), bromo acetyl bromide and 2-bromo propionylbromide as raw materials. These copolyesters all have a highly alternating sequence structure.…”