Synthesis and properties of readily recyclable polymers from bisfuranic terminated poly(ethylene adipate) and multi-maleimide linkers

Polymers that can repeatedly polymerize and depolymerize at moderate conditions was designed and synthesized. Furyl-telechelic poly(ethylene adipate) [PEA2F] was prepared and copolymerized with bis- and tris-maleimides by Diels-Alder [DA] reaction at 60 °C. Though the reaction with bismaleimide proceeded partially to give a polymer whose molecular weight was only twice as large as PEA2F, the reaction with trismaleimide gave a product with a 3D-network structure. The latter product shows elasticity at room temperature. By keeping at 145 °C, these DA products were easily disconnected by retro-Diels-Alder [rDA] reaction to reproduce the starting macromonomer, PEA2F. The repetition of the cycle of the DA and rDA reactions induce the reduction of neither the mechanical properties of the DA products nor the molecular weight of the rDA products. Therefore, we have successfully obtained readily recyclable polymers.