Synthesis and characterization of siloxane functionalized CO2-based polycarbonate

CO2-based polycarbonates are among the most promising eco-friendly polymers with excellent biodegradability and biocompatibility. However, the poor performance of conventional CO2-based polycarbonates such as poly(propylene carbonate) (PPC) and poly(cyclohexene oxide) (PCHC) limits their application. Herein, a series of siloxane functionalized CO2-based polycarbonates were obtained via terpolymerization of carbon dioxide (CO2), propylene oxide (PO), and [2-(3, 4-epoxycyclohexyl)-ethyl] trimethoxysilane (TMSO) using a SalenCoCl/PPNCl catalyst system. A systematic study of these polycarbonate's thermal, mechanical, and surface properties was conducted by tuning the ratio between TMSO and PO. The siloxane units offered polycarbonate with a higher surface energy, resulting in a water contact angle of 110° and a significant improvement in glass transition temperature (Tg) and decomposition temperature (Td). Additionally, the micro-crosslinked structure formed by the hydrolysis and condensation of methoxysilane groups provided to the polycarbonate's remarkable mechanical strength, with a high tensile strength of 46 MPa. As a result, a novel CO2-based polycarbonate derived from cost-efficient silane coupling agents and CO2 has shown promising results as an alternative to rigid plastics used in industry.