不同引发方式对环氧丙烷阴离子聚合的影响

Investigation on different initiation modes in the anionic polymerization of propylene oxide

以丙二醇、氢氧化钾为引发剂,引发环氧丙烷阴离子聚合,原料不同脱水方法对聚合引发效果进行了详细的分析和比较。结果表明,将丙二醇/冠醚较低温度下真空脱水,再加入KOH脱水,然后加入少量单体聚合,对聚合得到的低聚物进行高真空脱水,再以产物为引发剂,利用短链引发方式引发聚合得到的目标聚合物聚环氧丙烷,它具有相对分子质量高、相对分子质量分布窄的特点,且多分散系数可达到1.09。

Propylene oxide was polymerized with potassium hydroxide as catalyst and 1,2-propylene glycol as initiator. Different improved initiation modes were used in the polymerization. The results showed that higher relative molecular mass and much narrower relative molecular mass distribution were obtained by using the initiation mode with the process as follows： First, vacuum dehydration at a lower temperature of 1,2-propylene glycol/18- crown-6; Second, vacuum dehydration of 1, 2-propylene glycol/18-crown-6/KOH; Third, short chain initiator was formed by addition of a small amount of propylene oxide into the system then vacuum dehydrated at higher temperature; Finally, the dehydrated short chain initiator was used to initiate the polymerization of PPO. By using this initiation mode, PPO with MWD of 1.09, closer to monodispersion, was obtained.