Fecha de publicación: -- Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Improved ternary salophen-cobalt one-pot catalysis incorporating L-lactide into CO2-based polycarbonates enables high-M
w degradable terpolymers with improved thermal properties and controlled hydrolytic degradation.

ABSTRACT
The sustainable development of polycarbonates from greenhouse gases, like carbon dioxide (CO2), is of significant interest; however, achieving a high molecular weight polymer, with improved thermal properties and degradability remains challenging. This study reports the one-pot ring-opening polymerization of L-lactide (LLA), propylene oxide (PO), and CO2 to synthesize a degradable terpolymer by incorporating ester segments into a poly(propylene carbonate) (PPC) backbone using a novel ternary salophen-cobalt catalyst. The study systematically investigates the influence of reaction parameters on molecular weight (M
w), selectivity, monomer conversion, and PPC/PLA molar ratio. The resulting terpolymer achieves a high M
w of 139 kDa, under mild reaction conditions (60°C, 25 bar), and an improved glass transition temperature (T
g) of 46°C, notably higher than standard PPC (≤ 35°C). Degradation studies demonstrate the polymer's susceptibility to thermal, alkaline, and enzymatic hydrolysis, with up to a 36.6% reduction in M
w over 4 weeks. Furthermore, the study provides insight into the roles of each component within the ternary catalytic system, suggesting a synergistic function enabling a one-pot terpolymerisation of monomers with varying ring strains within a single catalytic framework.