Venkataraman Mohanapriya, Sözcü Sebnem, Militký Jiří
Department of Material Engineering, Faculty of Textile Engineering, Technical University of Liberec, Studentská 1402/2, 46117 Liberec, Czech Republic.
Gels. 2025 Jul 11;11(7):538. doi: 10.3390/gels11070538.
Fiber-aerogel composites have gained significant attention as high-performance thermal insulation materials due to their unique microstructure, which suppresses conductive, convective, and radiative heat transfer. At room temperature, silica aerogels in particular exhibit ultralow thermal conductivity (<0.02 W/m·K), which is two to three times lower than that of still air (0.026 W/m·K). Their brittle skeleton and high infrared transparency, however, restrict how well they insulate, particularly at high temperatures (>300 °C). Incorporating microscale fibers into the aerogel matrix enhances mechanical strength and reduces radiative heat transfer by increasing scattering and absorption. For instance, it has been demonstrated that adding glass fibers reduces radiative heat transmission by around 40% because of increased infrared scattering. This review explores the fundamental mechanisms governing radiative heat transfer in fiber-aerogel composites, emphasizing absorption, scattering, and extinction coefficients. We discuss recent advancements in fiber-reinforced aerogels, focusing on material selection, structural modifications, and predictive heat transfer models. Recent studies indicate that incorporating fiber volume fractions as low as 10% can reduce the thermal conductivity of composites by up to 30%, without compromising their mechanical integrity. Key analytical and experimental methods for determining radiative properties, including Fourier transform infrared (FTIR) spectroscopy and numerical modeling approaches, are examined. The emissivity and transmittance of fiber-aerogel composites have been successfully measured using FTIR spectroscopy; tests show that fiber reinforcement at high temperatures reduces emissivity by about 15%. We conclude by outlining the present issues and potential avenues for future research to optimize fiber-aerogel composites for high-temperature applications, including energy-efficient buildings (where long-term thermal stability is necessary), electronics thermal management systems, and aerospace (where temperatures may surpass 1000 °C), with a focus on improving the materials' affordability and scalability for industrial applications.
纤维气凝胶复合材料因其独特的微观结构而成为备受关注的高性能隔热材料，这种微观结构可抑制传导、对流和辐射热传递。在室温下，特别是二氧化硅气凝胶表现出超低的热导率（<0.02W/m·K），比静止空气的热导率（0.026W/m·K）低两到三倍。然而，它们易碎的骨架和高红外透明度限制了其隔热性能，尤其是在高温（>300°C）时。将微米级纤维掺入气凝胶基质中可提高机械强度，并通过增加散射和吸收来减少辐射热传递。例如，已经证明添加玻璃纤维由于增加了红外散射，可使辐射热传递降低约40%。本综述探讨了纤维气凝胶复合材料中辐射热传递的基本机制，重点是吸收、散射和消光系数。我们讨论了纤维增强气凝胶的最新进展，并着重于材料选择、结构改性和预测性热传递模型。最近的研究表明，掺入低至10%的纤维体积分数可使复合材料的热导率降低高达30%，而不会损害其机械完整性。研究了用于确定辐射特性的关键分析和实验方法，包括傅里叶变换红外（FTIR）光谱法和数值建模方法。已使用FTIR光谱法成功测量了纤维气凝胶复合材料的发射率和透射率；测试表明，高温下的纤维增强可使发射率降低约15%。我们通过概述当前问题和未来研究的潜在途径来得出结论，以优化用于高温应用的纤维气凝胶复合材料，包括节能建筑（需要长期热稳定性）、电子热管理系统和航空航天（温度可能超过1000°C），重点是提高材料在工业应用中的可承受性和可扩展性。
