β环糊精对苯乙烯无皂乳液聚合的影响

以苯乙烯为单体,过硫酸钾为引发剂,研究了β环糊精对无皂乳液聚合反应的影响.结果表明,环糊精的引入可以大大加快反应速度,提高单体转化率,并且反应速度随环糊精加入量的增加而增大;同时,环糊精的引入能够减小制得的聚合物微球的粒度分布,使聚合物微球的粒径大小更加均匀,而对粒径的影响不是很大.动力学分析的结果表明,环糊精可以提高单体的反应活性.当环糊精/单体比例增大到0.2时,单体反应活性是空白体系的3.3倍.

EFFECT OF β-CYCLODEXTRIN ON SOAP-FREE EMULSION POLYMERIZATION OF STYRENE

Cyclodextrins(CD),characterized by their biocompatibility,environmental amity,and low price,have been used in many fields.In recent years,their application in polymer chemistry attracts great attention.In this paper,using styrene as monomer,K_2S_2O_8 as initiator,we investigated the influence of β-CD on the soap-free emulsion polymerization of styrene.It is found that the addition of β-CD can greatly accelerate the polymerization,and increase the monomer conversion.With increase of the amount of CD,the reaction rate also increases.After 5 h,the monomer conversion,in absence of CD,is only 60.3%,which is much lower than that in presence of 1.0 g CD(90%).The final polymer particle-size distribution was more uniform than that without β-CD.The kinetic analysis indicated that β-CD could increase the monomer relative reactivity.AS the ratio of CD/monomer reaches 0.2,the monomer relative reactivity is more than 3 times of that in absence of CD.