Polyimide-based aerogel foams, via emulsion-templating
Polyimide-based aerogel foams, via emulsion-templating
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DOI：
10.1016/j.polymer.2018.10.030
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发表时间：
2018-11-21
期刊：
影响因子：
4.6
通讯作者：
Jana, Sadhan C.
中科院分区：
文献类型：
--
作者：
Teo, Nicholas;Gu, Zipeng;Jana, Sadhan C.
采用油包油乳液模板法制备聚酰亚胺气凝胶泡沫材料。这些材料含有微米尺寸的空隙（大空隙）以及聚酰亚胺凝胶中固有产生的中孔和大孔。首先由二胺和二酐合成聚酰胺酸，然后进行化学酰亚胺化以获得溶胶。通过乳化将不混溶的油型分散相引入溶胶中，随后使溶胶转变为凝胶，从而将分散相液滴锁定在结构内。随后将凝胶在超临界条件下干燥以获得气凝胶泡沫。本文根据连续相的凝胶时间评价了用于模板的油包油乳液的稳定性。具体来说，研究了表面活性剂浓度对气凝胶泡沫的大孔隙尺寸、中孔尺寸和机械性能的影响。此外，还研究了气凝胶泡沫的吸水和吸油行为。
An oil-in-oil emulsion-templating method is used to fabricate polyimide aerogel foam materials. These materials contain micrometer size voids (macrovoids) in conjunction with inherently produced meso- and macropores in polyimide gels. Polyamic acid is first synthesized from diamines and dianhydrides and then chemically imidized to obtain a sol. An immiscible oil-type dispersed phase is introduced in the sol via emulsification and the sol is subsequently allowed to transition into a gel, thereby locking the dispersed phase droplets within the structure. The gel is subsequently dried under supercritical conditions to obtain aerogel foams. This paper evaluates the stability of the oil-in-oil emulsion used for templating with reference to the gel times of the continuous phase. Specifically, the effects of surfactant concentration on macrovoid size, mesopore size, and mechanical properties of the aerogel foams are investigated. In addition, water and oil absorption behavior of the aerogel foams are studied.