中华医学超声杂志

应用化学 ›› 1994, Vol. 0 ›› Issue (6): 17-21.

• 研究论文 • 上一篇    下一篇

硅氧烷乳液聚合过程中大颗粒形成机理的研究Ⅱ.聚硅氧烷乳液的耐酸碱稳定性

黄英, 刘香鸾, 杨静   

  1. 中国科学院化学研究所 北京 100080
  • 收稿日期:1994-02-21 修回日期:1994-06-14 出版日期:1994-12-10 发布日期:1994-12-10
  • 基金资助:
    国家自然科学基金资助项目

Mechanism of Large Latex Particle Formation during Emusion Polymerization of Siloxanes Ⅱ.Stability of Polydimethylsiloxane Latices Towards Acid and Base

Huang Ying, Liu Xiangluan, Yang Jing   

  1. Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080
  • Received:1994-02-21 Revised:1994-06-14 Published:1994-12-10 Online:1994-12-10

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摘要： 研究了阴离子型与阳离子型聚硅氧烷乳液的耐酸碱稳定性。发现阴离子型乳液对酸碱都相当稳定,在乳液制备过程中,酸性催化剂不会引起乳液颗粒的凝聚;而阳离子型乳液的耐酸碱稳定性较差,尤其是引起乳液颗粒慢速凝聚的碱浓度下限值很低,碱是制备阳离子型乳液的催化剂,碱引起乳液颗粒的慢速凝聚是阳离子型乳液中大颗粒形成的主要原因。在乳液聚合过程中所发生的相当部分的乳化剂从水相向有机硅相的转移也是影响阳离子型乳液稳定性的一个重要因素。

关键词: 乳液聚合, 硅氧烷, 稳定性, 大乳液颗粒

Abstract: The stability of cationic and anionic polydimethylsiloxane latices towards acid and base was studied. It was found that the anionic latices were stable in the acid of concentration usually employed for catalytical polymerization. The stability of cationic latices was poor towards base, which is used as the catalyst of the polymerization. The limit sodium hydroxide concentration causing slow flocculation of cationic latices was lower than the concentration needed for the polymerization, so that the formation of large latex particles owing to flocculation could not be prevented during the emulsion polymerization. The transfer of a large part of the emulsifier from the aqueous phase to tpolysiloxane phase during the emulsion polymerization was also responsible for the formation of large latex particles.

Key words: emulsion polymerization, octamethylosiloxane, stability, large latex particle

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