气泡模板法制备超轻高回弹芳纶气凝胶

Preparation of ultralight aramid aerogels with high resilience by bubble template method

气泡模板在纳米材料液相组装过程中具有降低材料密度和调控结构的重要作用。但是,在芳纶纳米纤维液相组装过程中,由于芳纶纳米纤维稳定气泡的效果较差,导致难以使用气泡模板制备轻质芳纶纳米纤维气凝胶材料。因此,介绍了一种芳纶纳米纤维基气凝胶,该气凝胶是使用少量氧化石墨烯,加入芳纶纳米纤维水分散液中,利用气泡模板-冷冻干燥方法制备而成。具有高回弹、低密度的特点。加入固含量0.126%的氧化石墨烯即可显著提高气泡的稳定性,抑制气泡吞并速度,所制备的气凝胶在50%压缩应变时可完全回弹;而不添加氧化石墨烯制备的气凝胶其塑性形变可达28%,回弹性较差。此外,芳纶纳米纤维基气凝胶具有较低的密度(9.8 mg/cm^(3)),表现出优异的高温隔热性能。该轻质高回弹芳纶纳米纤维基气凝胶有望应用于新能源汽车、军工装备和航空航天等领域。

In the process of liquid-phase assembly of nano materials,bubble templates play a vital role in reducing material density and regulating structure.However,in the liquid-phase assembly process of aromatic polyamide nano fibers,the poor stability of aromatic polyamide nano fibers in stabilizing bubbles makes it difficult to prepare lightweight aromatic polyamide nano fiber aerogels using bubble templates.Therefore,a novel aromatic polyamide nano fiber-based aerogel is introduced.This aerogel,using a small amount of graphene oxide added to the aromatic polyamide nano fiber aqueous dispersion,is prepared using a bubble template-cryogenic freeze-drying method.It exhibits characteristics of high resilience and low density.The addition of graphene oxide at a solid content of 0.126%significantly improves the stability of bubbles,suppressing bubble coalescence rate.The prepared aerogel can fully rebound at 50%compression strain,while the aerogel prepared without graphene oxide shows plastic deformation up to 28%and poor resilience.Additionally,the aromatic polyamide nano fiber-based aerogel has a low density of 9.8 mg/cm^(3) and demonstrates excellent high-temperature insulation performance.This lightweight,highly resilient aromatic polyamide nano fiber-based aerogel is expected to be applied in fields such as new energy vehicles,military equipments,and aerospace.