Alicyclic polycarbonates

Although the synthesis of these polycarbonates has been accomplished, few reports have described the thermal and mechanical properties of these materials (21). To gain a better understanding of the potential applications for these materials, a variety of aliphatic and alicyclic polycarbonates must be synthesized and studied. 

Figure 5, Thermal properties of alicyclic polycarbonates poly(I J-cyclohexene carbonate) (PCHC), poly(limonene carbonate) (PLC), poly(4-vinyl- f2 cyclohexene carbonate) (PVCHC). (a) TGA thermograms (samples were run under an N2 atmosphere with a heating rate of 20 C/min). (b) DSC thermograms (samples were run under an N2 atmosphere with a heating and cooling rate of 10 C/min data shown are from the second heat).

The mechanical properties of the polyimide films (the sample size 10-mm length, 10-mm width) were examined at room temperature using a specially made machine with a constant drawing rate of 1 mm min"1. A profile of elongation vs. load for PI(BHDA+BBH) film is shown in Figure 4. The polyimide film possessed a tensile modulus of 2.1 GPa and a tensile strength of 52 MPa, and these values can compete in terms of strength with those of a commercial polycarbonate (PC).[8] The authors believe that this is the first example of a fully alicyclic polyimide for which the mechanical property was evaluated. 

As expected, the copolymerization of CHO and CO2 using catalyst 4 occurs rapidly under the previously reported optimized conditions (26) and has an activity similar to that of the most active catalysts reported to date (Table II, entry 1) (27). The isolated polycarbonate has >95% carbonate linkages and a narrow molecular weight distribution. Unlike the copolymerization of aliphatic epoxides, the copolymerization of alicyclic epoxides does not generate any of the cycloaddition product. 

---