From Fragile to Resilient Insulation: Synthesis and Characterization of Aramid-Honeycomb Reinforced Silica Aerogel Composite Materials

Schwan, Marina; Rößler, Matthias; Milow, Barbara; Ratke, Lorenz

doi:10.3390/gels2010001

Cited by 16 publications

(12 citation statements)

References 27 publications

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“…Silica aerogels have already been prepared with the addition of different aramid structures (fibers, pulp, honeycombs) [ 13 , 16 , 17 , 18 , 19 ]. However, none of them presented an organically modified silica system based on tetraethoxysilane (TEOS) and vinyltrimethoxysilane (VTMS), which can bring new interaction features between the fibers and the matrix.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Polyamide Pulp-Reinforced Silica Aerogel Composites for Thermal Protection Systems

et al. 2020

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The present work describes for the first time the preparation of silica-based aerogel composites containing tetraethoxysilane (TEOS) and vinyltrimethoxysilane (VTMS) reinforced with Kevlar® pulp. The developed system was extensively investigated, regarding its physical, morphological, thermal and mechanical features. The obtained bulk density values were satisfactory, down to 208 kg·m−3, and very good thermal properties were achieved—namely a thermal conductivity as low as 26 mW·m−1·K−1 (Hot Disk®) and thermal stability up to 550 °C. The introduction of VTMS offers a better dispersion of the polyamide fibers, as well as a higher hydrophobicity and thermal stability of the composites. The aerogels were also able to withstand five compression-decompression cycles without significant change of their size or microstructure. A design of experiment (DOE) was performed to assess the influence of different synthesis parameters, including silica co-precursors ratio, pulp amount and the solvent/Si molar ratio on the nanocomposite properties. The data obtained from the DOE allowed us to understand the significance of each parameter, offering reliable guidelines for the adjustment of the experimental procedure in order to achieve the optimum properties of the studied aerogel composites.

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Section: Introductionmentioning

confidence: 99%

Optimization of Polyamide Pulp-Reinforced Silica Aerogel Composites for Thermal Protection Systems

et al. 2020

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“…Powders are materials that influence the spectral properties of a polymer coating. In this study, the silica was introduced in the powder material to form silica-based aerogels in order to reduce considerably the material surface emissivity due to its over 90% reflectance versus the surrounding environment [9][10][11][12][13][14][15][16][17][18]. Moreover, glass microspheres were employed due to their similarity with silica-aerogels, as they embed in their structure a relatively big volume of air, and also due to their low expansion thermal coefficient that prevents the formation of cracks and a greater wettability potential [19][20][21][22][23][24][25].…”

Section: Resultsmentioning

confidence: 99%

“…Silica-based aerogels are powder materials obtained by extracting the liquid component from silicagel and replacing it with gas [10][11][12][13]. The result is a solid powder material, with an extremely low density.…”

Section: Analysis Methodsmentioning

confidence: 99%

Organic Coatings with Low IR Emission

Epure¹,

Țigănescu²,

Zecheru³

et al. 2021

Mater. Plast.

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A series of methods were employed to assess the performances of advanced coating materials based on components that can modify the spectral parameters of the surfaces on which these materials are applied in order to obtain passive military camouflage. Powder materials with high infrared (IR) reflectance were used to obtain this type of coatings, which also ingrain in their structure a significant volume of air that allow limitation of the radiative heat transfer of the coated source. The components were embedded in a polyurethane matrix, which facilitated the coating process on different surfaces. The bicomponent polyurethane-based binder used within the different composition tested is transparent to incident IR radiation, has no organic solvents, is highly flexible and possesses remarkable physical, chemical and mechanical properties: high surface adhesion, high flexibility and resistance against a number of chemical agents and external factors with destructive effect. The efficiency of these composite materials was further demonstrated by analyzing the thermal images of different objects.

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“…Currently, from the point of view of material composition, aerogels can be classified into the following categories: inorganic oxide aerogels (e.g., SiO 2 aerogels [ 6 ], TiO 2 aerogels [ 7 ], Al 2 O 3 aerogels [ 8 ]), organic aerogels (e.g., cellulose aerogels [ 9 ], polyurethane aerogels [ 10 ]), carbon aerogels (e.g., graphene aerogels [ 11 ], carbon nanotube aerogels [ 12 ]), and other aerogels (e.g., metal aerogels [ 13 ]). Aerogels are not only rich in material composition, but also have various microstructures of the gel skeleton.…”

Section: Introductionmentioning

confidence: 99%

Silica-Bacterial Cellulose Composite Aerogel Fibers with Excellent Mechanical Properties from Sodium Silicate Precursor

Song

Miao

Sai

et al. 2021

Gels

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Forming fibers for fabric insulation is difficult using aerogels, which have excellent thermal insulation performance but poor mechanical properties. A previous study proposed a novel method that could effectively improve the mechanical properties of aerogels and make them into fibers for use in fabric insulation. In this study, composite aerogel fibers (CAFs) with excellent mechanical properties and thermal insulation performance were prepared using a streamlined method. The wet bacterial cellulose (BC) matrix without freeze-drying directly was immersed in an inorganic precursor (silicate) solution, followed by initiating in situ sol-gel reaction under the action of acidic catalyst after secondary shaping. Finally, after surface modification and ambient drying of the wet composite gel, CAFs were obtained. The CAFs prepared by the simplified method still had favorable mechanical properties (tensile strength of 4.5 MPa) and excellent thermal insulation properties under extreme conditions (220 °C and −60 °C). In particular, compared with previous work, the presented CAFs preparation process is simpler and more environmentally friendly. In addition, the experimental costs were reduced. Furthermore, the obtained CAFs had high specific surface area (671.3 m²/g), excellent hydrophobicity, and low density (≤0.154 g/cm3). This streamlined method was proposed to prepare aerogel fibers with excellent performance to meet the requirements of wearable applications.

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From Fragile to Resilient Insulation: Synthesis and Characterization of Aramid-Honeycomb Reinforced Silica Aerogel Composite Materials

Cited by 16 publications

References 27 publications

Optimization of Polyamide Pulp-Reinforced Silica Aerogel Composites for Thermal Protection Systems

Optimization of Polyamide Pulp-Reinforced Silica Aerogel Composites for Thermal Protection Systems

Organic Coatings with Low IR Emission

Silica-Bacterial Cellulose Composite Aerogel Fibers with Excellent Mechanical Properties from Sodium Silicate Precursor

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