Preparation and Thermal Properties of Polycarbonates/esters Catalyzed by Using Dinuclear Salph-Al from Ring-Opening Polymerization of Epoxide Monomers.

A dinuclear Salph-Al complex/bis(triphenylphosphine)iminium chloride catalyst system was synthesized and employed for cyclohexene oxide (CHO) and CO₂ copolymerization. The catalyst system had an excellent selectivity of 99 % for carbonate linkages and the resultant poly(cyclohexene carbonate) (PCHC) had a high glass transition temperature ( T_g) of 123.8 °C and a thermal decomposition temperature (5 % weight loss; T_{d 5 %}) of 265 °C. Furthermore, this catalyst system was active in the polymerization of phthalic anhydride (PA) and epoxides. Poly(CHO- alt-PA) was completely alternating, and had improved thermal properties ( T_g=142.7 and T_{d 5 %}=295 °C) compared with PCHC. The T_g values of the polyesters could be adjusted by addition of PO to the CHO/PA reaction system. For the CHO/PO/PA terpolymerization, CHO and PO participated concurrently and proportionally in the chain growth and the obtained terpolyesters had tunable T_g values from 62.8 to 142.7 °C depending on the CHO/PO feed ratio. [ABSTRACT FROM AUTHOR]