(AB) _n Star Block Polymers Derived from CO₂: Influence of Architecture and Postpolymerization Modification

The utilization of CO₂ as a sustainable feedstock for oxygenated polymers offers a promising route to high-performance materials while addressing environmental challenges. This study investigates the synthesis of high-molar-mass, nonlinear polymer architectures using switchable catalysis, focusing on multiarm star block polymers derived from vinyl-cyclohexene oxide (vCHO), CO₂, and ε-decalactone (ε-DL). A [Zn-(II)-Mg-(II)] organometallic catalyst and multifunctional chain-transfer agents (CTAs) are employed in a "core-first" approach to produce tri-, tetra-, and hexafunctional star block polymers. Thermomechanical and morphological properties were evaluated as a function of molar mass, number of arms, and architecture, indicating the differences between star and linear structures. Postpolymerization modification of the polycarbonate block, via thiol-ene chemistry, introduced pendant hydroxyl groups, enhancing hydrogen bonding and microphase separation, significantly impacting thermal and mechanical performance. This work highlights the versatility of switchable catalysis in accessing star polymers while underscoring the potential of integrating architectural control and functionalization to enhance the performance and applicability of CO₂-derived poly-(ester-b-carbonate)-s.