Morphology and surface area of emulsion-derived (PolyHIPE) solid foams prepared with oil-phase soluble porogenic solvents: Span 80 as surfactant
Morphology and surface area of emulsion-derived (PolyHIPE) solid foams prepared with oil-phase soluble porogenic solvents: Span 80 as surfactant
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DOI：
10.1021/ma0359436
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发表时间：
2004-05-04
期刊：
影响因子：
5.5
通讯作者：
Cameron, NR
中科院分区：
文献类型：
--
作者：
Barbetta, A;Cameron, NR
在油相中用致孔剂（甲苯、氯苯、(2-氯乙基)苯、1,2-二氯苯和1-氯-3-苯基丙烷）制备的聚（二乙烯基苯）乳液衍生（PolyHIPE）固体泡沫的形态和表面积很大程度上受致孔剂性质的影响。对于使用 Span 80 的表面活性剂的情况，我们表明固体泡沫结构取决于 (i) 溶剂溶胀生长网络的能力，(ii) 溶剂极性，以及 (iii) 溶剂在乳液界面吸附的能力。特别是，能够通过乳液连续相（奥斯特瓦尔德熟化）输送水的相对极性溶剂显示出比仅在所讨论的溶剂存在下通过二乙烯基苯的均相溶液聚合制备的类似树脂低得多的表面积。奥斯特瓦尔德熟化的影响通过如下观察得到进一步表明：对于相对极性的溶剂，表面积随着乳液水相含量的增加而减小，而对于疏水性较高的溶剂，观察到表面积随水相含量的变化很小。所有制备的 PolyHIPE 均通过 SEM、TEM、N-2 吸附分析和压汞孔隙率测定法进行表征。讨论了 TEM 和压汞孔隙率测定法作为固体泡沫可靠表征技术的相对优点。
Poly(divinylbenzene) emulsion-derived (PolyHIPE) solid foams prepared with porogens (toluene, chlorobenzene, (2-chloroethyl)benzene, 1,2-dichlorobenzene, and 1-chloro-3-phenylpropane) in the oil phase have morphologies and surface areas that are strongly influenced by the nature of the porogen. For the case where the surfactant employed is Span 80, we show that the solid foam structure depends on (i) the ability of the solvent to swell the growing network, (ii) the solvent polarity, and (iii) the ability of the solvent to adsorb at the emulsion interface. In particular, relatively polar solvents that are able to transport water through the emulsion continuous phase (Ostwald ripening) are shown to produce much lower surface areas than analogous resins prepared by homogeneous solution polymerization of divinylbenzene in the presence of the solvent in question alone. The influence of Ostwald ripening is further suggested by the observation that surface area decreases with increasing emulsion aqueous phase content for relatively polar solvents whereas little variation in surface area with aqueous phase content is observed for more hydrophobic solvents. All PolyHIPEs prepared were characterized by SEM, TEM, N-2 sorption analysis, and mercury intrusion porosimetry. The relative merits of TEM and mercury intrusion porosimetry as techniques for the reliable characterization of the solid foams are discussed.