Aramid-Coating-on-Aramid 制造强韧可折叠聚合物气凝胶薄膜的策略,ACS Nano

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Aramid-Coating-on-Aramid 制造强韧可折叠聚合物气凝胶薄膜的策略
ACS Nano ( IF 15.8 ) Pub Date : 2022-08-22 , DOI: 10.1021/acsnano.2c04572
Shixuan Yang ₁ , Chunjie Xie ₁ , Teng Qiu ₂ , Xinlin Tuo ₁

Affiliation

气凝胶作为一种新兴的轻质隔热材料备受关注，但易碎、强度低、液体渗透性差、缺乏柔韧性等问题极大地限制了进一步的应用。在这项工作中，展示了一种简便的芳纶涂层芳纶（ACoA）方法来制造用于隔热的全芳纶气凝胶复合薄膜。该方法从聚合诱导对位的自下而上合成开始-芳纶纳米纤维（PANF），通过真空辅助过滤和冷冻干燥技术很容易转化为气凝胶薄膜。然后，将通过低温溶液缩聚制备的杂环芳纶（HA）溶液作为涂层应用于PANF气凝胶薄膜上，简单地实现了HA/PANF气凝胶的复合薄膜，HA有助于致密且连续的表层。块状 HA 薄膜具有优于 PANF 薄膜的机械和热性能。此外，通过渗透的 HA 与 PANF 网络的互穿，在最外表面下方形成了可靠的界面联锁结构。综合结果是抗拉强度提高了15倍，断裂韧性提高了33倍，HA/PANF 气凝胶的可折叠薄膜具有较高的热分解温度和额外的灵活性。表面大孔的封闭极大地抑制了表面粉化和高吸水率。然而，复合材料内部微小孔隙的存在保持了足够低的导热率水平，不仅可以在空气中而且在潮湿甚至液体条件下提供有效的高温保护，这表明隔热材料具有更广泛的应用。

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The Aramid-Coating-on-Aramid Strategy toward Strong, Tough, and Foldable Polymer Aerogel Films

Aerogel has been much highlighted as an emerging lightweight thermal insulation material, but problems such as fragility, low strength, liquid permeability, and lack of flexibility greatly limit further applications. In this work, a facile aramid-coating-on-aramid (ACoA) method is demonstrated to fabricate all-aramid aerogel composite films for thermal insulation. The method started from the bottom-up synthesis of polymerization-induced para-aramid nanofibers (PANF), which were easily transformed into aerogel films through the vacuum-assisted filtration followed by the freeze-drying techniques. Then, the heterocyclic aramid (HA) solution prepared through the low-temperature-solution polycondensation was used as the coating to be applied onto the PANF aerogel films, and composite films of HA/PANF aerogel were simply achieved with HA contributed to the dense and continuous surface layer. The bulk HA film is of superior mechanical and thermal properties to those of the PANF film. Moreover, reliable interfacial interlocking structures were developed beneath the outermost surface via the interpenetration of the infiltrated HA with PANF network. The comprehensive result was the 15 times enhanced tensile strength, 33 times enhanced fracture toughness, the high thermal decomposition temperature, and the additional flexibility for the foldable films of HA/PANF aerogel. The sealing of the surface macropores greatly suppressed the surface chalking and high water absorption. However, the survival of the tiny pores inside the composite maintained the low enough level of the thermal conductivity to provide effective protections against high temperature not only in air but also under wet or even liquid conditions, suggesting the broader applications for thermal insulation.

更新日期：2022-08-22

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