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POLYMERIZATION OF octamethylcyclotetrasiloxane WITH HEXAMETHYLDISILAZYL-LITHIUM AS INITIATOR

Chinese Journal of Polymer Science 2001年第1期19卷 7-11页

作者： Zhijie Zhang Ning Zhou Cai-hong Xu Ze-min Xie Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

This work focused on the anionic polymerization of octamethylcyclotetrasiloxane (D-4, D = Me2SiO2/2) initiated by a new kind of initiator hexamethydisilazyl-lithium (MMNLi). Si-29-NMR spectroscopy and gas chromatography (GC) were used to characterize the polymerization products. The process was accelerated by adding a small amount of high activity monomer D-3 and by raising the polymerization temperature. At the end of polymerization more than 95% of the monomer was converted to polymer and only a very small amount of D-4 and D-5 remained in the polymers.

关键词： high purity polydimethylsiloxane octamethylcyclotetrasiloxane hexamethyldisilazyl-lithium anionic polymerization

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Cationic Ring Opening Polymerization of octamethylcyclotetrasiloxane Initiated by Acid Treated Bentonite

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Chinese Journal of Chemical Engineering 2007年第5期15卷 661-665页

作者：陈碧詹晓力易玲敏陈丰秋 College of Material Science and Chemical Engineering Zhejiang University Hangzhou 310027 China

Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary *** 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.

关键词： octamethylcyclotetrasiloxane cationic polymerization polysiloxane

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Kinetics of Bulk Polymerization of Octamethylcyclote- trasiloxane

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Chinese Journal of Chemical Engineering 2004年第1期12卷 156-158页

作者：方欣陈志荣尹红苏科峰 Department of Chemical Engineering College of Materials Science and Chemical Engineering Zhejiang University Hangzhou 310027 China Deprtment of Chemical Engineering College of Materials Science and Chemical Engineering Zhejiang University Hangzhou 310027 China

The kinetics of bulk polymerization of octamethylcyclotetrasiloxane under acid circumstance is studied. A kinetic model is put forward and kinetic parameters are obtained through optimization.

关键词： octamethylcyclotetrasiloxane polymerization kinetics mathematical model optimization

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