Modular Access from Acrylate to a Sustainable Polyester Platform with Large-Span Tunability and Chemical Circularity under Mild Conditions

Making polyesters with conventional vinyl monomers is one of the most economical ways to develop sustainable polymeric materials. For polar vinyls, while their transformation into lactones has been studied extensively, there exists no further access to synthesizing polyesters, presumably due to the nonstrained and nonpolymerizable nature of the obtained lactones. Herein, we report the first facile synthesis of polyesters that originated from one of the most critical classes of polar vinyls-acrylates. Specifically, a series of modular six-membered lactones were rationally designed and synthesized from methyl acrylate together with malonic esters containing diverse functional groups and formaldehyde. The monomers underwent ring-opening polymerization (ROP) to yield the first acrylate-derived polyesters, which further constitute a unique polymer platform with a large scope of potential functionalities and performances as well as easy chemical circularity under mild conditions. Notably, the obtained polyesters are a rare example featuring tunable functionalities on the side ester groups whose impact on certain material properties (e.g., glass transition temperature) is similar to that of polyacrylates, implying potential replacement between polyesters and polyacrylates. In addition, by presenting the special geminal disubstitutions originally from the monomers' γ-position for the first time, polyesters also exhibited unprecedentedly enhanced thermal and recycling properties: Variation of the geminal disubstitutions offers a unique access to large-span modulation from completely amorphous to high-level crystalline materials, and the melting temperature of the polymer with high crystallinity was drastically increased by 84 °C compared with the reported monosubstituted counterpart. At the same time, compared with polyesters synthesized from other six-membered lactones whose chemical recycling required harsh conditions (>150 °C and high vacuum), the gem-disubstituted polyesters in this work can undergo complete chemical recycling to monomers under much milder conditions (80 °C and ambient pressure). This study informs the design of future high-performance polyesters derived from polar vinyls.