关键词:

羟基聚硅氧烷, 水, 一步合成, 动力学模型

Abstract: Hydroxy terminated polydimethylsiloxane (PDMS) is one of the important silicone products. In this paper, PDMS was synthesized in one-step process with cyclosiloxanes as monomer and a base as initiator when the reaction was under the conditions of high temperature, adding water and oxygen-off. The kinetics of the reaction was studied by Gel Permeation Chromatography (GPC). Furthermore, from the reaction conditions of one-step process, the chemical features of such one-step process could be expressed as anionic ring-opening polymerization of cyclosiloxanes under the influence of water. So based on the classical mechanism study on anionic ring-opening polymerization of cyclosiloxanes,the reaction mechanism of such one-step process was proposed, the kinetic model of the one-step process was derived. The change of the concentration of active centers with the progress of reaction was quantitatively obtained according to the kinetic model. There are three periods:sluggish period, increasing period, and constant period. The results described above were also verified by examining the complex structure of the reaction mixture with infrared spectroscopy(IR).

Key words:

羟基聚硅氧烷, 水, 一步合成, 动力学模型