Synthesis of emulsion-templated poly(acrylamide) using CO2-in-water emulsions and poly(vinyl acetate)-based block copolymer surfactants
Synthesis of emulsion-templated poly(acrylamide) using CO2-in-water emulsions and poly(vinyl acetate)-based block copolymer surfactants
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DOI：
10.1021/ma062518e
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发表时间：
2007-02
期刊：
影响因子：
5.5
通讯作者：
B. Tan;Jun-Young Lee;A. Cooper
中科院分区：
文献类型：
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作者：
B. Tan;Jun-Young Lee;A. Cooper
我们在这里提出了一个简单的和通用的方法，用于生产廉价的和可生物降解的聚合物表面活性剂在超临界CO2。以异丙基乙醇（IPE）为链转移剂，采用优化的反应条件合成了低分子量（Mw < 7000 g/mol）端羟基聚醋酸乙烯酯（PVAc−OH）。然后通过超临界流体分馏获得低聚PVAc−OH（OVAc−OH，Mw < 3000 g/mol）。OVAc−OH物质通过与羰基二咪唑（CDI）反应转化为咪唑酯，并通过将这些反应性嵌段与聚乙二醇甲基醚或聚乙二醇二醇偶联来制备可溶于CO2的表面活性剂。发现表面活性剂在生产稳定的水包CO2（C/W）乳液中非常有效，然后将其用作模板以生产乳液模板材料，该材料具有前所未有的高孔隙率。结果表明，这些烃类表面活性剂的性能优于其它烃类表面活性剂。
We present here a simple and generic method for producing inexpensive and biodegradable polymer surfactants for use in supercritical CO2. Low molecular weight (Mw < 7000 g/mol) hydroxyl-terminated poly(vinyl acetate) (PVAc−OH) was synthesized using optimized reaction conditions and isopropyl ethanol (IPE) as the chain transfer agent. Oligomeric PVAc−OH (OVAc−OH, Mw < 3000 g/mol) was then obtained by supercritical fluid fractionation. The OVAc−OH species was converted to the imidazole ester by reaction with carbonyl diimidazole (CDI) and CO2-soluble surfactants were produced by coupling these reactive blocks with poly(ethylene glycol) methyl ethers or poly(ethylene glycol) diols. The surfactants found to be extremely effective in the production of stable CO2-in-water (C/W) emulsions, which were then used as templates to produce emulsion-templated materials with unprecedentedly high levels of porosity for materials produced by this route. It was shown that these hydrocarbon surfactants can out-perform perfl...