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jingjingll

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[交流] 关于破乳的问题

冰冻破乳是什么机理呢？非离子做乳化剂的时候能冰冻破乳吗？谢谢了

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1楼 2011-07-21 10:27:18

已阅回复此楼关注TA 给TA发消息送TA红花 TA的回帖

qiuxuesha

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小木虫(金币+0.5):给个红包，谢谢回帖

我也下载不了，有个文章是BASF发的，读完你就清楚里面的原因了。

http://www.springerlink.com/content/w547772337678t71/

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

espite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing.