Moisture-Resistant and Mechanically Strong Polyimide-Polymethylsilsesquioxane Hybrid Aerogels with Tunable Microstructure
Moisture-Resistant and Mechanically Strong Polyimide-Polymethylsilsesquioxane Hybrid Aerogels with Tunable Microstructure
复制标题
具有可调微结构的防潮且机械强度高的聚酰亚胺-聚甲基倍半硅氧烷杂化气凝胶
DOI：
10.1002/mame.202000612
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发表时间：
2021
影响因子：
3.9
通讯作者：
Shen Jun
中科院分区：
文献类型：
--
作者：
Xi Shuang;Wang Xiaodong;Liu Ting;Zhang Ze;Zhang Xiaoxue;Shen Jun
采用溶胶-凝胶技术和超临界CO2流体干燥法合成了具有双交联结构的耐湿、机械强度高的聚酰亚胺（PI）-聚甲基倍半硅氧烷杂化气凝胶。通过使用双（三甲氧基甲硅烷基丙基）胺作为交联剂，使用甲基三甲氧基硅烷作为二氧化硅源前体，将衍生自联苯-3，3 ′，4，4 ′-四羧酸二酐和4，4 ′-二氨基二苯醚的封端聚酰胺酸与二氧化硅网络交联。所得的杂化气凝胶显示出低密度（0.12-0.15 g cm-3）、低热导率（0.032-0.049 W m-1 K-1）、高疏水性（125-140°）和良好的热稳定性（高于435 °C）以及可调节的微观结构。随着硅溶胶体积的增加，杂化气凝胶的微观结构由纤维状网络结构向分级结构转变。具有高含量的硅溶胶的气凝胶表现出良好的耐湿性、高杨氏模量（最大值）、低粘度和高粘度。19.6 MPa）和高比模量（Max. 131 kN m kg−1），这归因于它们独特的具有片状骨架的分层显微结构。这种杂化气凝胶在隔热、航空航天等领域具有广阔的应用前景。
Moisture‐resistant and mechanically strong polyimide (PI)‐polymethylsilsesquioxane hybrid aerogels with doubly cross‐linked structures are synthesized through sol–gel technology and supercritical CO2fluid drying. By using bis(trimethoxysilylpropyl) amine as a cross‐linker, the end‐capped polyamide acid derived from biphenyl‐3,3′,4,4′‐tetracarboxylic dianhydride and 4,4′‐oxydianiline is cross‐linked with a silica network using methyltrimethoxysilane as the silica source precursor. The resultant hybrid aerogels show low density (0.12–0.15 g cm−3), low thermal conductivity (0.032–0.049 W m−1K−1), high hydrophobicity (125–140°) and good thermal stability (above 435 °C) with tunable microstructure. With the increase of silica sol volume, the microstructure of hybrid aerogels transforms from fibrous network to hierarchical microstructure. Aerogels with high content of silica sol exhibit good moisture resistance, high Young's modulus (Max. 19.6 MPa), and high specific modulus (Max. 131 kN m kg−1), which are attributed to their unique hierarchical microstructure with a sheet skeleton. These hybrid aerogels are promising in the fields of thermal insulation, aerospace applications and so on.