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.

• Keywords
• FTIR analysis, aerogel composites, fibrous aerogels, heat transfer, radiative heat transfer,
• Publication type
• Journal Article MeSH
• Review MeSH

Bacterial cellulose (BC) synthesized by Acetobacter xylinum has gained significant attention due to its unique structural and functional properties. This study focuses on the simple, facile, and cost-effective synthesis of bacterial cellulose films from Acetobacter xylinum and evaluates their impact on selected properties. The BC films were prepared through a series of controlled fermentation, purification, and drying processes, optimizing their porosity and structural integrity with different stabilization forms (the BC films supported by polyester nonwoven (PES NW) fabric) by a static culture method keeping with the sustainability. The selected properties like density, porosity, surface roughness, thermal conductivity, and the wetting properties of surfaces are tested. These properties were chosen because they significantly impact the performance of BC aerogels in the potential application of aerogels in biomedical, insulation, and filtration industries. The results indicated that the synthesized BC aerogels exhibit a highly porous network, lightweight structure, and excellent thermal conductivity, making them suitable for advanced material applications. This research highlights the potential of bacterial cellulose aerogels as sustainable (without any additives/chemicals) and high-performance materials, paving the way for further advancements in bio-based aerogels.

• Keywords
• Acetobacter xylinum bacteria, bacterial cellulose aerogel, lyophilization,
• Publication type
• Journal Article MeSH

Bacterial cellulose (BC) presents significant promise as a biomaterial, boasting unique qualities such as exceptional cellulose purity, robust mechanical strength, heightened crystalline structure, and biodegradability. Several studies have highlighted specific effects, such as the impact of dehydration/rehydration on BC tensile strength, the influence of polymer treatment methods on mechanical properties, the correlation between microorganism type, drying method, and Young's modulus value, and the relationship between culture medium composition, pH, and crystallinity. Drying methods are crucial to the structure, performance, and application of BC films. Research findings indicate that the method used for drying can influence the mechanical properties of BC films, including parameters such as tensile strength, Young's modulus, and water absorption capacity, as well as the micromorphology, crystallinity, and thermal characteristics of the material. Their versatility makes them potential biomaterials applicable in various fields, including thermal and acoustic insulation, owing to their distinct thermal and mechanical attributes. This review delves into the thermal and mechanical behavior of bacterial cellulose aerogels, which are profoundly impacted by their drying mechanism.

• Keywords
• bacterial cellulose hydrogel, drying methods, lyophilization, structure, thermal and mechanical behavior,
• Publication type
• Journal Article MeSH
• Review MeSH