Incorporation of nonionic emulsifiers inside particles in emulsion polymerization: mechanism and methods of suppression.
Incorporation of nonionic emulsifiers inside particles in emulsion polymerization: mechanism and methods of suppression.
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DOI：
10.1021/la061429s
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发表时间：
2006-10
期刊：
影响因子：
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通讯作者：
M. Okubo;Hiroshi Kobayashi;Takumi Matoba;Y. Oshima
中科院分区：
文献类型：
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作者：
M. Okubo;Hiroshi Kobayashi;Takumi Matoba;Y. Oshima
使用具有不同亲水亲油平衡（HLB）的两种聚氧乙烯月桂基醚非离子乳化剂：Emulgen 109P（HLB 13.6）和Emulgen 150（HLB 18.3）进行苯乙烯的乳液聚合。在这两种情况下，乳化剂掺入聚苯乙烯（PS）颗粒内清楚地观察到，如先前报道的苯乙烯和甲基丙烯酸的乳液聚合使用聚氧乙烯壬基苯基醚（Emulgen 911，HLB 13.7）非离子乳化剂。阐明了乳液聚合中非离子乳化剂掺入聚合物粒子现象的普遍性。在比Emulgen 150更疏水的Emulgen 109 P的情况下，约30%的总量掺入PS颗粒内，高于Emulgen 150（15%）。这种差异似乎归因于非离子乳化剂与苯乙烯之间亲和力的差异，这导致了乳化剂的掺入。在此基础上，通过降低聚合温度和单体进料速率来抑制掺入。这有力地支持了拟议的纳入机制。
Emulsion polymerizations of styrene were carried out using two kinds of polyoxyethylene lauryl ether nonionic emulsifiers having different hydrophilic-lipophilic balances (HLB): Emulgen 109P (HLB 13.6); and Emulgen 150 (HLB 18.3). In both cases, incorporation of emulsifier inside polystyrene (PS) particles was clearly observed, as previously reported for the emulsion polymerization of styrene and methacrylic acid using polyoxyethylene nonyl phenyl ether (Emulgen 911, HLB 13.7) nonionic emulsifier. The generality of the incorporation phenomenon of nonionic emulsifier inside polymer particles in emulsion polymerization was clarified. In the case of Emulgen 109P, which is more hydrophobic than Emulgen 150, about 30% of the total amount was incorporated inside the PS particles, higher than for Emulgen 150 (15%). The difference seemed to be ascribed to the difference in the affinities between the nonionic emulsifiers and styrene, which cause the incorporation of emulsifier. On the basis of this idea, suppression of the incorporation was achieved by decreasing the polymerization temperature and the monomer-feed rate. This strongly supports the proposed incorporation mechanism.