School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Pan Asia Microvent Tech (Jiangsu) Corporation & Zhejiang University Micro-nano-porous Materials United Research Development Center, Changzhou 213100, China.
Molecules. 2019 Mar 30;24(7):1246. doi: 10.3390/molecules24071246.
With methylsilsesquioxane (MSQ) aerogels synthesized by the sol-gel method as a raw material and Si-Ti sol as a binder, an alcohol-based aerogel slurry consisting of only MSQ aerogel and Si-Ti sol was prepared and coated on expanded polytetrafluoroethylene (ePTFE) to form an MSQ aerogel coating layer, followed by low-temperature heat treatment. The effect of Si-Ti sol content on the microstructure of the MSQ aerogel coating layer was investigated, and the properties of a typical MSQ aerogel-layer-coated ePTFE film were evaluated. The results show that Si-Ti sol has an important role in terms of film-forming capability, surface smoothness, flexibility, and powder dropping of the MSQ aerogel coating layer. With a Si-Ti sol of 10.5 wt.% content as a binder and after heat treatment at 170 °C for 30 min, the coated ePTFE flexible thin film with a layer thickness of 30 μm shows high uniformity, integrity, and electrical insulation properties, with an elongation at break decrease over 130%, a thermal conductivity of 0.1753 W/(m·K) at 25 °C, a dielectric constant of 16.5674, and a dielectric loss of 0.06369, which can be promisingly applied in cable sheaths.
以溶胶-凝胶法合成的甲基倍半硅氧烷（MSQ）气凝胶为原料，硅钛溶胶为粘结剂，制备了仅由 MSQ 气凝胶和硅钛溶胶组成的醇基气凝胶浆料，并将其涂覆在膨胀聚四氟乙烯（ePTFE）上形成 MSQ 气凝胶涂层，然后进行低温热处理。考察了硅钛溶胶含量对 MSQ 气凝胶涂层微观结构的影响，并对典型的 MSQ 气凝胶层涂覆 ePTFE 薄膜的性能进行了评估。结果表明，硅钛溶胶在成膜能力、表面平整度、柔韧性和 MSQ 气凝胶涂层的粉末脱落方面具有重要作用。以 10.5wt.%的硅钛溶胶为粘结剂，在 170°C 下热处理 30min，得到的涂覆 ePTFE 柔性薄膜层厚为 30μm，具有较高的均匀性、完整性和电绝缘性能，断裂伸长率增加超过 130%，25°C 时的热导率为 0.1753W/（m·K），介电常数为 16.5674，介电损耗为 0.06369，有望应用于电缆护套。
