CO2-based polycarbonates from biobased cyclic terpenes with end-of-life usage potential

Abstract

Biobased polymers have garnered increasing attention in recent years, aiming at more sustainable materials. This study focuses on the synthesis of polycarbonates sourced from cyclic terpenoid-based monomers and CO2, representing polymers derived from a biobased feedstock. Menthyl, thymyl, and carvacryl glycidyl ethers, synthesized from menthol, thymol, and carvacrol and epichlorohydrin were copolymerized with CO2 using catalytic systems such as (R,R)-(salcy)-Co(III)Cl (Co(Salen)Cl) and bis(triphenylphosphine)-iminium chloride ([PPN]Cl) or triethylborane (TEB)/[PPN]Cl. Moderate to high molar mass polymers (up to 60 kg mol−1) were obtained with low dispersities (Mw/Mn < 1.24) via solvent-free bulk copolymerization. Despite the sterically demanding nature of these monomers, the cobalt-based catalyst system exhibited high monomer conversion, polymer selectivity, and carbonate linkage content. The resulting polycarbonates exhibited glass transition temperatures (Tg) ranging from 41 to 58 °C, when the polymer backb