Polymer Science Group, Department of Chemical and Bimolecular Engineering, University of Melbourne, Parkville, VIC 3010, Australia.
Langmuir. 2010 Jun 1;26(11):9023-31. doi: 10.1021/la904827d.
A series of surfactants were designed and synthesized for use as clay modification reagents to investigate the impact of their chemical structure on the nanocomposites morphology obtained following polymerization. The behavior of the surfactant-modified clays at three different stages were investigated: after ion exchange, following dispersion in styrene monomer, and once polymerization was complete. The propensity of the styrene monomer to swell the surfactant-modified clay was observed to be a useful indicator of compatibility and predictor of the resultant polystyrene nanocomposite morphology which was directly observed using small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (TEM). It was found that the key components of surfactant design driving exfoliated morphologies were (1) the position of the ammonium group, (2) the inclusion of a polymerizable group, (3) the solubility of the surfactant in the monomer, (4) the length of the alkyl chain, and (5) sufficient concentration of surfactant used to exchange the clay. This understanding should lead to better design of clay modifications for use in polymer nanocomposites.
设计并合成了一系列表面活性剂，用作粘土改性试剂，以研究其化学结构对聚合后获得的纳米复合材料形态的影响。研究了表面活性剂改性粘土在三个不同阶段的行为：离子交换后、分散在苯乙烯单体中以及聚合完全后。观察到苯乙烯单体溶胀表面活性剂改性粘土的倾向是相容性的有用指标，也是所得聚苯乙烯纳米复合材料形态的预测指标，这可以直接使用小角 X 射线散射 (SAXS) 和低温透射电子显微镜 (TEM) 观察到。研究发现，驱动剥离形态的表面活性剂设计的关键因素包括：(1) 铵基的位置，(2) 可聚合基团的包含，(3) 表面活性剂在单体中的溶解度，(4) 烷基链的长度，以及 (5) 用于交换粘土的表面活性剂的足够浓度。这种理解应该会导致更好地设计用于聚合物纳米复合材料的粘土改性。
