含1,2-亚乙基单元的双酚A聚碳酸酯非光气法合成和表征

以双酚A(BPA),碳酸乙二酯(EC)和碳酸二甲酯(DMC)为原料,制备双酚A二元醇(Ⅰ)和双酚A碳酸酯(Ⅱ),并用红外光谱与核磁共振波谱对其结构进行表征.通过Ⅰ与Ⅱ的共缩聚反应及Ⅱ的自聚实现了主链中含有—CH2CH2—单元的双酚A型聚碳酸酯(PC)的非光气法合成,用凝胶渗透色谱法(GPC)和TGA-DSC对PC的分子量和热性质进行分析.结果表明,Ⅱ在240℃自聚6h后产物的Mn可达17.6×103,主链中—CH2CH2—单元的引入,可以降低聚合物的Tg,提高其结晶性,所得聚合物具有良好的热稳定性.

A NONPHOSGENE PROCESS FOR BISPHENOL-A POLYCARBONATE WITH ETHYLENE UNITS AND CHARACTERIZATION OF THE POLYMER

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 17.6 ×103.The Tg of PC (Mn = 12.4 ×103) 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.