Polyester Networks from Radical Ring-Opening Polymerization

Radical ring-opening polymerization (RROP) of cyclic ketene acetals (CKAs) constitutes a powerful route to accessing degradable polyesters with unique properties. These multifaceted materials are mainly known as linear polymers. Polymer networks based on RROP have been scarcely described in the literature, and existing studies have focused mainly on incorporating complementary proportions of degradable units through RROP. The current study fills this critical gap and reports the synthesis and comprehensive characterization of polymer networks solely derived from RROP of CKAs, providing key insights into the network formation as well as the underpinning structure–property-relationship. Specifically, 2-methylene-1,3,6-trioxocane (MTC) was utilized as the main CKA building block in conjunction with a CKA cross-linker as well as a vinyl ether-based cross-linker. The polymer network formation was performed in bulk and in solution to exploit the solvent’s mediating effect. Subsequent comprehensive analysis of the gels’ macroscopic properties revealed the formation of hydrophobic 3D networks with storage moduli ranging from 1.9 to 312 kPa in the dry state, depending on the kind and amount of the employed cross-linker and the presence of solvent. In addition, the degradation behavior of these materials under alkaline conditions was examined, evidencing their susceptibility to rapid hydrolysis. These readily degradable hydrolyzable networks from RROP with tailored mechanical strength might hold promise in different fields of application ranging from 3D cell culture to polymeric scaffolds in tissue engineering.