Synthesis and characterization of high molecular weight poly(1,2-propylene carbonate-co-1,2-cyclohexylene carbonate) using zinc complex catalyst

Using supported multi-component zinc dicarboxylate catalyst, poly(1,2-propylene carbonate-co-1,2-cyclohexylene carbonate) (PPCHC) was successfully synthesized from carbon dioxide (CO₂) with propylene oxide (PO) and cyclohexene oxide (CHO). The conversion of epoxides dramatically increased up to 89.7% (yield: 384.2 g of polymer per g of Zn) with increasing reaction temperature from 60°C to 80°C. The optimized reaction temperature is 80°C. The chemical structure, the molecular weight, as well as thermal and mechanical properties of the resulting terpolymers were investigated extensively. When CHO feed content (mol%) is lower than 10%, the PPCHC terpolymers have number average molecular weight (M _n) ranging from 102 × 10³ to 202 × 10³ and molecular weight distribution (MWD) values ranging from 2.8 to 3.5. In contrast to poly(propylene carbonate) (PPC), the introduction of small amount of CHO leads to increase in the glass transition temperature from 38.0°C to 42.6°C. Similarly, the mechanical strength of the synthesized terpolymer is greatly enhanced due to the incorporation of CHO. These improvements in mechanical and thermal properties are of importance for the practical application of PPC.