Cationic Ring Opening Polymerization of Octamethylcyclotetrasiloxane Initiated by Acid Treated Bentonite  

作　　者：陈碧 詹晓力 易玲敏 陈丰秋 

机构地区：[1]College of Material Science and Chemical Engineering, Zhejiang University, Hangzhou 310027, China

出　　处：《Chinese Journal of Chemical Engineering》2007年第5期661-665,共5页中国化学工程学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China （No.20576117）

摘　　要：Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher temperature was found beneficial for the reaction process while stirring intensity beyond a certain level showed no obvious effect on the reaction rate. Polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance （IH-NMR） and gel perneation chromotography. The width of molecular mass distribution was found ranging between 1.2 and 1.4, which is extraordinarlly narrow compared with that of cationic polymerizations reported elsewhere （〉 1.9）. The results were believed due to the absence of free proton and counter ion which simplifies the polymerization process and the huge steric hindrance provided by bentonite particles which keeps the propagation of polysiloxane onto the surface of bentonite particles in a much more regular way. A feasible mechanism is proposed and seems to be supported well by experiments. Additionally, from the results of α, ω-dihydrogen terminated polysiloxanes prepared, the possibility of applying this potential environmentally friendly heterogeneous catalyst in industrial polymerization of cyclosiloxanes is anticipated.酸开始的 octamethylcyclotetrasiloxane (D4 ) 的 Cationic 戒指开始聚合对待火山灰成胶状黏土被调查。试验性的条件根据初步的实验被选择。当在某个水平以外的激动人心的紧张没在反应率上显示出明显的效果时，更高的温度为反应过程被发现有益。聚合物被 Fourier 变换描绘红外线，质子原子磁性的回声(1H-NMR ) 和胶化浸透 chromotography。分子的集体分发的宽度被发现在 1.2 和 1.4 之间变化，它与离子的聚合在其它地方报导了的猫(>1.9 ) 的相比是非常地狭窄的。结果由于简化聚合过程和把 polysiloxane 的繁殖放在到火山灰成胶状黏土粒子的表面上一个更常规的方法的火山灰成胶状黏土粒子提供的巨大的位的阻碍者的免费质子和相反的离子的缺席被相信。可行机制被建议并且似乎被实验支持很好。另外，从结果，ω - dihydrogen 终止了准备的 polysiloxanes，在 cyclosiloxanes 的工业聚合的友好异构的催化剂被期望的使用这个潜在的环境联盟者的可能性。

关 键 词：OCTAMETHYLCYCLOTETRASILOXANE cationic polymerization POLYSILOXANE 

分 类 号：O643.3[理学—物理化学]