Fatty acid epoxides and carbon dioxide have been used as monomers to create functional polycarbonate macromolecules using catalytic ring-opening copolymerizations, providing molecular weights of up to 18.5 kg/mol under controlled conditions. The functionality in these polycarbonates can be controlled via either the pendent ester groups or using additional (functional) epoxy monomers, thereby creating terpolymeric compositions with cross-linkable or polarity-changing fragments. Potential depolymerization and upcycling of the polycarbonate atoms were investigated, allowing repurposing of the initial macromolecule into a bifunctional diurethane-diester monomer in good yield. The prospect of using bioderived polycarbonates as additives in biogel formulations was evaluated, showing it to improve the mechanical and adsorption properties of castor oil-based polyurethane gels.