Fabrication and Characterization of MSQ Aerogel Coating on ePTFE Thin Films for Cable Sheaths

• Published in: Molecules (Basel, Switzerland) Vol. 24; no. 7; p. 1246
• Main Authors: Guo, Xingzhong, Bai, Shengchi, Shan, Jiaqi, Lei, Wei, Ding, Ronghua, Zhang, Yun, Yang, Hui
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30.03.2019; MDPI
• Subjects: aerogel coating; cable sheath; Cables; Coating; Coatings; Dielectric constant; Dielectric loss; Dielectric properties; Electrical insulation; Elongation; ePTFE; Fabrication; Flexibility; Heat conductivity; Heat treatment; Heat treatments; Low temperature; Mechanical Phenomena; Mechanical properties; Membranes, Artificial; MSQ aerogel; Nanoparticles; Organosilicon Compounds - chemistry; Particle Size; Polytetrafluoroethylene - chemistry; Polyvinyl alcohol; Sheaths; Silicone Gels - chemistry; Slurries; Smoothness; Sol-gel processes; Solvents; Surface Properties; Thermal Conductivity; Thickness; Thin films; Titanium - chemistry; cable sheath; ePTFE; aerogel coating; MSQ aerogel
• ISSN: 1420-3049; 1420-3049
• 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.