The reaction of bisphenol A (BPA) with ethylene carbonate (EC) promoted by Bu2SnO at 180℃ produces dihydroxyethylbisphenol A (Ⅰ) along with the liberation of CO2.The influence of temperature on the reaction of EC and BPA is investigated by FTIR.The diol Ⅰ reacted with dimethyl carbonate (DMC) at 120℃ to generate bisphenol A carbonate (Ⅱ) in yield of 96%.Their structures were characterized by FTIR and NMR.A novel nonphosgene process for producing bisphenolA polycarbonate (PC) was developed through the self transesterification of Ⅱ and cotransesterification of Ⅰ and Ⅱ.The self transesterification of Ⅱ is much faster than cotransesterification of Ⅰ and Ⅱ. The reaction temperature strongly affects the molecular weight of polycarbonate.NMR

gel permeation chromatography (GPC)

differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to measure the molecular structure and thermodynamic properties.The average number molecular weight of PC obtained from the selfpolymerization of Ⅱ for 6 h at 240℃ is up to 17.6103 .The Tg of PC (Mn = 12.4103) is about 60℃

which is much lower than that of the regular PC (Tg = 145~150℃).The introduction of CH2CH2 unit into the main chain can reduce the Tg of PC and increase the crystallization ability.The obtained PC has a good thermal stability.