A review of recent progress on the silica aerogel monoliths: synthesis, reinforcement, and applications

Lin, Jiming; Li, Guangze; Liu, Wei; Qiu, Ruoxiang; Wei, Huanyi; Zong, Kai; Cai, Xingke

doi:10.1007/s10853-021-05997-w

Cited by 62 publications

(29 citation statements)

References 100 publications

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“…This improvement of the mechanical performance can be based on the control of the internal network structure during the synthesis of the aerogel or on the addition of a reinforcing phase. The fragility of the internal structure is due to the thin necks joining the silica nanoparticles, and the brittleness of the O-Si-O bonds under an impact force [ 1 , 7 , 8 ]. The addition of carbon nanotubes (CNTs) has been used in several recent works such as the one of Lamy-Mendes et al [ 9 ] who synthesized reinforced CNTs-silica aerogels with improved physical and mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Silica-Based Aerogel Composites Reinforced with Reticulated Polyurethane Foams: Thermal and Mechanical Properties

Merillas

Lamy-Mendes

Villafañe

et al. 2022

Gels

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In this work, silica aerogel composites reinforced with reticulated polyurethane (PU) foams have been manufactured having densities in the range from 117 to 266 kg/m3 and porosities between 85.7 and 92.3%. Two different drying processes were employed (ambient pressure drying and supercritical drying) and a surface modification step was applied to some of the silica formulations. These composites, together with the reference PU foam and the monolithic silica aerogels, were fully characterized in terms of their textural properties, mechanical properties and thermal conductivities. The surface modification with hexamethyldisilazane (HMDZ) proved to improve the cohesion between the reticulated foam and the silica aerogels, giving rise to a continuous network of aerogel reinforced by a polyurethane porous structure. The samples dried under supercritical conditions showed the best interaction between matrixes as well as mechanical and insulating properties. These samples present better mechanical properties than the monolithic aerogels having a higher elastic modulus (from 130 to 450 kPa), a really exceptional flexibility and resilience, and the capacity of being deformed without breaking. Moreover, these silica aerogel-polyurethane foam (Sil-PU) composites showed an excellent insulating capacity, reaching thermal conductivities as low as 14 mW/(m·K).

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Section: Introductionmentioning

confidence: 99%

Silica-Based Aerogel Composites Reinforced with Reticulated Polyurethane Foams: Thermal and Mechanical Properties

Merillas

Lamy-Mendes

Villafañe

et al. 2022

Gels

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“…Due to the difference in synthesis method, physical and weak phase interactions exist among secondary Si particles in this sol–gel technique produced mesoporous silica, which is prone to be damaged by high voltage electronic beam. [ 20 , 21 ] Therefore, we optimize the shooting method of SEM by keeping a low voltage and using integration mode (Figure S1 , Supporting Information). The transmission electron microscope (TEM) detection is also attempted.…”

Section: Resultsmentioning

confidence: 99%

Mesopore Controls the Responses of Blood Clot‐Immune Complex via Modulating Fibrin Network

Shan

Xie

et al. 2021

Advanced Science

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Formation of blood clots, particularly the fibrin network and fibrin network‐mediated early inflammatory responses, plays a critical role in determining the eventual tissue repair or regeneration following an injury. Owing to the potential role of fibrin network in mediating clot‐immune responses, it is of great importance to determine whether clot‐immune responses can be regulated via modulating the parameters of fibrin network. Since the diameter of D‐terminal of a fibrinogen molecule is 9 nm, four different pore sizes (2, 8, 14, and 20 nm) are rationally selected to design mesoporous silica to control the fibrinogen adsorption and modulate the subsequent fibrin formation process. The fiber becomes thinner and the contact area with macrophages decreases when the pore diameters of mesoporous silica are greater than 9 nm. Importantly, these thinner fibers grown in pores with diameters larger than 9 nm inhibit the M1‐polorazation of macrophages and reduce the productions of pro‐inflammatory cytokines and chemokines by macrophages. These thinner fibers reduce inflammation of macrophages through a potential signaling pathway of cell adhesion‐cytoskeleton assembly‐inflammatory responses. Thus, the successful regulation of the clot‐immune responses via tuning of the mesoporous pore sizes indicates the feasibility of developing advanced clot‐immune regulatory materials.

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“…By designing inorganic nanoporous products, their thermal resistance must be significantly increased [ 35 ]. One of the best materials of this type is silica aerogel [ 36 ], however, it is prohibitively expensive. Therefore, alternatives are needed, especially those that could use locally mined or otherwise sourced raw materials.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of High Crystallinity 1.13 nm Tobermorite and Xonotlite from Natural Rocks, Their Properties and Application for Heat-Resistant Products

et al. 2022

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The main measure to reduce energy losses is the usage of insulating materials. When the temperature exceeds 500 °C, silicate and ceramic products are most commonly used. In this work, high-crystallinity 1.13 nm tobermorite and xonotlite were hydrothermally synthesized from lime and Ca–Si sedimentary rock, opoka. By XRD, DSC, TG and dilatometry methods, it has been shown that 1.13 nm tobermorite becomes the predominant compound in stirred suspensions at 200 °C after 4 h of synthesis in the mixture with a molar ratio CaO/SiO2 = 0.83. It is suitable for the production of insulating products with good physical–mechanical properties (average density < 200 kg·m−1, compressive strength ~0.9 MPa) but has a limited operating temperature (up to 700 °C). Sufficiently pure xonotlite should be used to obtain materials with a higher operating temperature. Even small amounts of semi-amorphous C–S–H(I) significantly increase its linear shrinkage during firing. It has also been observed that an increase in the strength values of the samples correlated well with the increase in the size of xonotlite crystallites. The optimal technological parameters are as follows: molar ratio of mixture CaO/SiO2 = 1.2; water/solid ratio W/S = 20.0; duration of hydrothermal synthesis at 220 °C—8 h, duration of autoclaving at 220 °C—4 h. The average density of the samples was ~180 kg·m−1, the operating temperature was at least 1000 °C, and the compressive strengths exceeded 1.5 MPa.

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A review of recent progress on the silica aerogel monoliths: synthesis, reinforcement, and applications

Cited by 62 publications

References 100 publications

Silica-Based Aerogel Composites Reinforced with Reticulated Polyurethane Foams: Thermal and Mechanical Properties

Silica-Based Aerogel Composites Reinforced with Reticulated Polyurethane Foams: Thermal and Mechanical Properties

Mesopore Controls the Responses of Blood Clot‐Immune Complex via Modulating Fibrin Network

Synthesis of High Crystallinity 1.13 nm Tobermorite and Xonotlite from Natural Rocks, Their Properties and Application for Heat-Resistant Products

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