Synthesis of sterically stabilized polystyrene latex particles using cationic block copolymers and macromonomers and their application as stimulus-responsive particulate emulsifiers for oil-in-water emulsions
Synthesis of sterically stabilized polystyrene latex particles using cationic block copolymers and macromonomers and their application as stimulus-responsive particulate emulsifiers for oil-in-water emulsions
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DOI：
10.1021/la035921c
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发表时间：
2004-05-25
期刊：
影响因子：
3.9
通讯作者：
Whitby, CP
中科院分区：
文献类型：
--
作者：
Amalvy, JI;Unali, GF;Whitby, CP
采用基团转移聚合的方法，将2-（二甲氨基）甲基丙烯酸乙酯（DMA）与甲基丙烯酸甲酯（MMA）进行嵌段共聚，得到4种低分散性（M-w/M-n < 1.20）的AB二嵌段、ABA三嵌段和BAB三嵌段共聚物。此外，以4-乙烯基苄基醇钾为引发剂，通过氧阴离子聚合合成了近单分散苯乙烯功能化的dma基大单体。这五种定义明确的、以甲基丙烯酸叔胺为基础的共聚物被评价为通过乳液和分散聚合合成聚苯乙烯乳胶的立体稳定剂。最有效的立体稳定剂是DMA-MMA二嵌段共聚物和dma基大单体。采用动态光散射、扫描电子显微镜、H-1核磁共振波谱、水电泳和表面张力测定等方法对聚苯乙烯乳液的粒径、形貌、稳定剂含量、表面电荷和表面活性进行了表征。所选择的乳液所表现出的ph依赖性表面活性表明，作为刺激响应颗粒乳化剂可能应用于水包油乳液。
2-(Dimethylamino)ethyl methacrylate (DMA) was block copolymerized with methyl methacrylate (MMA) using group transfer polymerization to give four AB diblock, ABA triblock, and BAB triblock copolymers of low polydispersity (M-w/M-n < 1.20). In addition, a near-monodisperse styrene-functionalized DMA-based macromonomer was synthesized via oxyanionic polymerization using a potassium 4-vinylbenzyl alcoholate initiator. These five well-defined, tertiary amine methacrylate-based copolymers were evaluated as steric stabilizers for the synthesis of polystyrene latexes via emulsion and dispersion polymerization. The most efficient steric stabilizers proved to be the DMA-MMA diblock copolymer and the DMA-based macromonomer. The polystyrene latexes were characterized in terms of their particle size and morphology, stabilizer content, surface charge, and surface activity using dynamic light scattering, scanning electron microscopy, H-1 NMR spectroscopy, aqueous electrophoresis measurements, and surface tensiometry, respectively. The pH-dependent surface activity exhibited by selected latexes suggests potential applications as stimulus-responsive particulate emulsifiers for oil-in-water emulsions.