Di Luigi Massimigliano, Guo Zipeng, An Lu, Armstrong Jason N, Zhou Chi, Ren Shenqiang
Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York Buffalo 14260 New York USA
Department of Industrial and Systems Engineering, University at Buffalo, The State University of New York Buffalo 14260 New York USA
RSC Adv. 2022 Aug 1;12(33):21213-21222. doi: 10.1039/d2ra03325a. eCollection 2022 Jul 21.
Achieving a mesoporous structure in superinsulation materials is pivotal for guaranteeing a harmonious relationship between low thermal conductivity, high porosity, and low density. Herein, we report silica-based cryogel and aerogel materials by implementing freeze-drying and ambient-pressure-drying processes respectively. The obtained freeze-dried cryogels yield thermal conductivity of 23 mW m K, with specific surface area of 369.4 m g, and porosity of 96.7%, whereas ambient-pressure-dried aerogels exhibit thermal conductivity of 23.6 mW m K, specific surface area of 473.8 m g, and porosity of 97.4%. In addition, the fiber-reinforced nanocomposites obtained freeze-drying feature a low thermal conductivity (28.0 mW m K) and high mechanical properties (∼620 kPa maximum compressive stress and Young's modulus of 715 kPa), coupled with advanced flame-retardant capabilities, while the composite materials from the ambient pressure drying process have thermal conductivity of 28.8 mW m K, ∼200 kPa maximum compressive stress and Young's modulus of 612 kPa respectively. The aforementioned results highlight the capabilities of both drying processes for the development of thermal insulation materials for energy-efficient applications.
在超级隔热材料中实现介孔结构对于确保低导热率、高孔隙率和低密度之间的协调关系至关重要。在此，我们分别通过冷冻干燥和常压干燥工艺报道了基于二氧化硅的冷冻凝胶和气凝胶材料。所得冷冻干燥的冷冻凝胶的热导率为23 mW m⁻¹ K⁻¹，比表面积为369.4 m² g⁻¹，孔隙率为96.7%，而常压干燥的气凝胶的热导率为23.6 mW m⁻¹ K⁻¹，比表面积为473.8 m² g⁻¹，孔隙率为97.4%。此外，通过冷冻干燥获得的纤维增强纳米复合材料具有低导热率（28.0 mW m⁻¹ K⁻¹）和高机械性能（最大压缩应力约为620 kPa，杨氏模量为715 kPa），以及先进的阻燃能力，而常压干燥工艺制备的复合材料的热导率为28.8 mW m⁻¹ K⁻¹，最大压缩应力约为200 kPa，杨氏模量为612 kPa。上述结果突出了这两种干燥工艺在开发节能应用隔热材料方面的能力。
