Sustainable bio-based polyesters organocatalyzed ring-opening alternating copolymerization and their adhesive applications

Abstract

Ring-opening alternating copolymerization (ROAP) of the bio-derived monomer 3,4-dihydrocoumarin (DHC) with epoxides represents a promising route to sustainable aromatic polyesters. However, existing catalytic systems often suffer from limited monomer scope and insufficient molar mass control due to undesired transesterification side reactions. Herein, we report a two-component organocatalytic system composed of organobases and triethylborane for the ROAP of DHC with various epoxides. This strategy affords well-defined aromatic polyesters with perfectly alternating sequences, relatively high molar masses (up to 10 kg mol−1), and narrow molar mass distributions (Đ < 1.25). The catalytic system exhibits broad monomer compatibility, enabling the copolymerization of DHC with propylene oxide, 1,2-butylene oxide, styrene oxide, allyl glycidyl ether, glycidyl methacrylate, cyclohexene oxide, and 4-vinylcyclohexene oxide. Furthermore, block copolymers with (AB)nCm and (AB)n(CB)m architectures are synthesized in a one-pot manner via sequential monomer addition following the ROAP stage. The resulting bio-based polyesters exhibit excellent thermal stability and undergo facile degradation under mild conditions. Moreover, a crosslinked formulation based on P(DHC-alt-AGE) demonstrates adhesive performance comparable to or surpassing that of commercial adhesives. This work provides an efficient platform for the controlled synthesis of DHC-based aromatic polyesters and highlights their potential as sustainable adhesive materials.