Influence of camphorsulfonic acid in nitroxide‐mediated styrene miniemulsion polymerization
Influence of camphorsulfonic acid in nitroxide‐mediated styrene miniemulsion polymerization
复制标题
樟脑磺酸对硝基氧介导的苯乙烯细乳液聚合的影响
DOI：
10.1002/pola.10377
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
M. Georges
中科院分区：
文献类型：
--
作者：
M. Cunningham;K. Tortosa;Marcus Lin;B. Keoshkerian;M. Georges
研究了磺酸（CSA）对氮氧自由基介导的苯乙烯细乳液聚合的加速作用。以过氧化苯甲酰（BPO）为引发剂引发聚合，并用2，2，6，6-四甲基哌啶氧基（克里思）或4-羟基-2，2，6，6-四甲基哌啶氧基（OH-TEMPO）介导。虽然CSA已被用于加速本体氮氧自由基介导的聚合反应的速率，它还没有得到很好的研究，在乳液/细乳液。对于分散体系，CSA的有效性可能受到水相和有机相之间的分配的影响。在一系列条件下进行的苯乙烯细乳液实验中，添加CSA的效果从可忽略不计到显著增加最终转化率和分子量不等，这取决于氮氧自由基：BPO的比例。在氮氧自由基：BPO = 1.7的比率下，CSA添加的效果很小，而当氮氧自由基：BPO的比率为3.6时，CSA添加显著提高了最终转化率和分子量。当初始游离氮氧浓度较高时，CSA在提高速率和分子量方面是最有效的。克里思和OH-TEMPO的速率和分子量增强的幅度相似，尽管它们在水溶性方面存在差异。© 2002 Wiley Periodicals，Inc.聚合物科学杂志A部分：聚合物化学40：2828-2841，2002年
The rate-accelerating effects of camphorsulfonic acid (CSA) on nitroxide-mediated styrene miniemulsion polymerization were studied. Polymerizations were initiated with benzoyl peroxide (BPO) as an initiator and mediated with either 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) or 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (OH-TEMPO). Although CSA has been used to accelerate the rate in bulk nitroxide-mediated polymerizations, it has not been well studied in emulsion/miniemulsion. With dispersed systems, the effectiveness of CSA is likely to be affected by partitioning between the aqueous and organic phases. In styrene miniemulsion experiments performed over a range of conditions, the effect of adding CSA varied from negligible to significantly increasing the final conversion and molecular weight, depending on the nitroxide:BPO ratio. At a ratio of nitroxide:BPO = 1.7, the effect of CSA addition is small, whereas the final conversion and molecular weight are dramatically enhanced by CSA addition when the nitroxide:BPO ratio is 3.6. CSA is most effective in enhancing the rate and molecular weight when the initial free-nitroxide concentration is higher. The magnitude of the rate and molecular weight enhancement was similar for TEMPO and OH-TEMPO despite their differences in water solubility. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2828–2841, 2002