分散聚合反应中苯乙烯转化率的测定

CONVERSION PERCENTAGE OF MONOMER DURING STYRENE DISPERSION POLYMERIZATION

用三溴络合物溴加成方法，研究苯乙烯分散聚合反应过程中单体转化率．研究结果发现，稳定剂聚乙烯基吡咯烷酮浓度对单体聚合反应转化率的影响很大．当稳定剂用量低于０．２ｇ／Ｌ时，苯乙烯的转化率很低，而当用量高于０．２５ｇ／Ｌ时，单体转化率大幅度提高，说明稳定剂既起到稳定成核的作用，还影响自由基的活性．增加苯乙烯浓度会提高单体转化率。

This paper studies the dispersion polymerization of styrene in alcohol/water medium,using α,α  azobisisobutylonitrile as an initiator and polyN vinylpyrrolidone as a steric stabilizer analyzes and the conversion percentage of monomers during the polymerization by bromine addition.The experimental results indicate that the concentration of the stabilizer has great effect on the rate of polymerization.When PVP amount was lower than 0.2 g/L,the polymerization ability of styrene was very low.This phenomenon was first discovered,and it explains that PVP not only acted as a stabilizer to form nuclei,but also affected the activity of the radical.Increasing the polarity of the medium and monomer concentration can increase the polymerization ability of styrene.