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Polycarbonate diols(PCDLs) with a number average molecular weight(Mn) of 2800 and a narrow polydispersity index(PDI=1.33) were synthesized from dimethyl carbonate(DMC) and 1,4-butanediol(BD) viaa two-step process. The influences of the molar ratios of DMC to BD in the feedstock, polycondensation temperature and polycondensation time on the PCDLs preparation were studied. CH3COONa showed the best catalytic performance among the catalysts studied. The highest BD conversion of 73.8% and PCDLs yield of 64.7% were achieved under its optimum reaction conditions. Furthermore, based on the results of 1H NMR, the relationships between the ratio of end groups (—OCH3/—OH) of oligomers, the Mnand chainend constitute of resultant polycarbonates were also investigated. The results indicate that PCDLs can be synthesized when the oligomers mostly bear hydroxyl end groups. In contrast, it was impossible to prepare PCDLs when the oligomers were enriched with methyl carbonate end groups.

High-molecular-weight aliphatic polycarbonates(APCs) were synthesized through a two-step transesterification process under solvent-free conditions. Oligomers with equal numbers of hydroxyl and phenyl carbonate terminal groups could be easily controlled by using equimolar amounts of diphenyl carbonate(DPC) and aliphatic diols as feedstocks in the first step. In the second step, the high-molecular-weight APCs can be obtained by connecting ―OH with OC(O)OC6H5end-group upon removing the generated phenol at reduced pressure. Mg(OAc)2was found to be the best catalyst for this process among the screened catalysts, which gave the poly(1,4-butylene carbonate)(PBC) a weight-average molecular weight(Mw) of 148600 and a yield of 84.8% under its suitable reaction conditions. In addition, based on the results of X-ray diffraction(XRD), scanning electron microscopy(SEM) and fourier transform infrared spectroscopy(FTIR), a possible reaction mechanism over Mg(OAc)2was proposed for APCs synthesis.