(AB)n型聚醚嵌段改性有机硅的合成及其在消泡剂中的应用

在氯铂酸-异丙醇溶液的催化作用下,通过双端基含氢硅油(PHMS)与双烯丙基聚氧乙烯聚氧丙烯醚(AAF)发生硅氢加成反应制备(AB)n型聚醚嵌段改性硅油(PBMS),并对其结构进行红外表征。将PBMS与MQ硅树脂、二甲基硅油、疏水白炭黑等活性组分复配制成消泡剂乳液。从消泡活性物的研制入手,探讨了这些活性组分的质量分数、PBMS的结构、硅油链的长短和聚醚(AAF)相对分子质量(简称分子量,下同)的大小对消泡剂主要应用性能的影响。结果表明:该消泡剂乳液消泡时间7.8 s,抑泡时间达到45.8 min,且在高温(65℃)碱性(pH=12)条件下放置24 h,乳液不分层,不漂油。

Synthesis of (AB)n polyether-block-polysiloxane and its application in defoaming agent

A new type of(AB)n polyether-block-polysiloxanes(PBMS) was synthesized by hydrosilylation reaction of Si—H terminated polydimethylsiloxane with allyl-polyoxyethylene-polyoxypropylene(AAF) in the presence of H2PtCl6-isopropyl alcohol.And its chemical structure was characterized by means of FTIR spectroscopy.The defoaming agent emulsion was formulated from polydimethylsiloxane,hydrophobic silicon dioxide,MQ silicone resin,the PBMS and so on.Starting from the preparation of silicone defoaming surfactants,the conditions that affect the defoaming and inhibiting performance,such as the mass fraction of these defoaming surfactants,PBMS with different structures,the length of silicon chain and the molecular weight of AAF polyether,were investigated.The experimental results show that the defoaming agent could rapidly break down 100 mL bubble in 7.8 s,with bubble-restrain time of 45.8 min,and there was no delamination,no emulsion breaking under the base condition(pH =12) and at high temperature(65 ℃) for 24 h.