scholarly journals Development of a New Silica Aerogel-Polypropylene Foam Composite as a Highly Flexible Thermal Insulation Material

2021 ◽  
Vol 8 ◽  
Author(s):  
Satoshi Yoda ◽  
Satoru Takeshita ◽  
Takumi Ono ◽  
Ryosuke Tada ◽  
Hideo Ota
Keyword(s):  
Thermal Insulation ◽  
Silica Aerogel ◽  
Large Scale ◽  
Volume Ratio ◽  
Supercritical Drying ◽  
Scale Production ◽  
Insulation Material ◽  
Polymer Foam ◽  
Practical Applications ◽  
Foam Composite

A new flexible thermal insulation sheet, a composite of silica aerogel with polypropylene (PP) foam, has been developed. Even though a large volume ratio of silica aerogel (97%) was included, the composite showed high flexibility. Thermal conductivity of the composite was 0.016 W/(m⋅K) at 298 K, which is as low as silica aerogel monolith. Silica aerogel flaking, which has been a problem in practical applications, is very low in this composite due to skin layers of the polymer-foam composite. A supercritical drying process for rolled sheets of the material for large-scale production is also described. Simulations of extraction of 2-propanol from a silica alcogel revealed that rolled composite sheets with small spaces between the sheet composite are able to dry in a reasonable extraction time. These findings led to effective on production of this material on a pilot industrial scale.

scholarly journals Continuous, Strong, Porous Silk Firoin-Based Aerogel Fibers toward Textile Thermal Insulation

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1899 ◽  
Author(s):  
Haiwei Yang ◽  
Zongqian Wang ◽  
Zhi Liu ◽  
Huan Cheng ◽  
Changlong Li
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Hollow Fiber ◽  
High Performance ◽  
Large Scale ◽  
Low Density ◽  
Potential Candidate ◽  
Scale Production ◽  
Insulation Material ◽  
High Porosity

Aerogel fiber, with the characteristics of ultra-low density, ultra-high porosity, and high specific surface area, is the most potential candidate for manufacturing wearable thermal insulation material. However, aerogel fibers generally show weak mechanical properties and complex preparation processes. Herein, through firstly preparing a cellulose acetate/polyacrylic acid (CA/PAA) hollow fiber using coaxial wet-spinning followed by injecting the silk fibroin (SF) solution into the hollow fiber, the CA/PAA-wrapped SF aerogel fibers toward textile thermal insulation were successfully constructed after freeze-drying. The sheath (CA/PAA hollow fiber) possesses a multiscale porous structure, including micropores (11.37 ± 4.01 μm), sub-micron pores (217.47 ± 46.16 nm), as well as nanopores on the inner (44.00 ± 21.65 nm) and outer (36.43 ± 17.55 nm) surfaces, which is crucial to the formation of a SF aerogel core. Furthermore, the porous CA/PAA-wrapped SF aerogel fibers have many advantages, such as low density (0.21 g/cm3), high porosity (86%), high strength at break (2.6 ± 0.4 MPa), as well as potential continuous and large-scale production. The delicate structure of multiscale porous sheath and ultra-low-density SF aerogel core synergistically inhibit air circulation and limit convective heat transfer. Meanwhile, the high porosity of aerogel fibers weakens heat transfer and the SF aerogel cellular walls prevent infrared radiation. The results show that the mat composed of these aerogel fibers exhibits excellent thermal insulating properties with a wide working temperature from −20 to 100 °C. Therefore, this SF-based aerogel fiber can be considered as a practical option for high performance thermal insulation.

scholarly journals Cost-Effective Additive Manufacturing of Ambient Pressure-dried Silica Aerogel

2020 ◽  
pp. 1-32
Author(s):  
Zipeng Guo ◽  
Ruizhe Yang ◽  
Tianjiao Wang ◽  
Lu An ◽  
Shenqiang Ren ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Silica Aerogel ◽  
Processing Time ◽  
Ambient Pressure ◽  
Cost Effective ◽  
Supercritical Drying ◽  
Insulation Material ◽  
Market Demand ◽  
Insulation Property ◽  
Insulation Performance

Abstract The conventional manufacturing processes of aerogel insulation material is largely relying on the supercritical drying, which suffers from issues of massive energy consumption, high-cost equipment, and prolonged processing time. With the consideration of large market demand of the aerogel insulation material in the next decade, a low-cost and scalable fabrication technique is highly desired. In this paper, a direct ink writing (DIW) method is used to three-dimensionally fabricate the silica aerogel insulation material, followed by room-temperature and ambient pressure drying. Compared to the supercritical drying and freeze-drying, the reported method significantly reduces the fabrication time and costs. The cost-effective DIW technique offers the capability to print complex hollow internal structures, coupled with the porous structure, is found to be beneficial to the thermal insulation property. The addition of fiber to the ink assures the durability of the fabricated product, without sacrificing the thermal insulation performance. The foam ink preparation methods and the printability are demonstrated in this paper, along with the printing of complex three-dimensional geometries. The thermal insulation performance of the printed objects is characterized, and the mechanical properties are also examined. The proposed approach is found to have 56% reduction in the processing time. The printed silica aerogels exhibit a low thermal conductivity of 0.053 W m−1 K−1.

Experimental Study on Cost-Effective Additive Manufacturing of Silica Aerogel

2020 ◽  
Author(s):  
Zipeng Guo ◽  
Ruizhe Yang ◽  
Tianjiao Wang ◽  
Lu An ◽  
Shenqiang Ren ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Silica Aerogel ◽  
Low Cost ◽  
Ambient Pressure ◽  
Cost Effective ◽  
Supercritical Drying ◽  
Ambient Pressure Drying ◽  
Insulation Material ◽  
Market Demand ◽  
Insulation Property

Abstract The conventional manufacturing process of aerogel insulation material relies largely on the supercritical drying, which suffers from issues of massive energy consumption, high-cost equipment and prolonged processing time. With the consideration of large market demand of the aerogel insulation material in the next decade, a low-cost and scalable fabrication technique is highly desired. In this paper, a direct ink writing (DIW) method is used to three-dimensionally fabricate the silica aerogel insulation material, followed by room-temperature and ambient pressure drying. Compared to the supercritical drying and freeze-drying, the reported method significantly reduces the fabrication time and costs. The cost-effective DIW technique offers the capability to print complex hollow internal structures, coupled with the porous structure, is found to be beneficial to the thermal insulation property. The addition of fiber to the ink assures the durability of the fabricated product. The foam ink preparation methods and the printability are demonstrated in this paper, along with the printed samples for characterizing thermal insulation performance and mechanical properties.

scholarly journals A Green Approach for Highly Reduction of Graphene Oxide by Supercritical Fluid

2014 ◽  
Vol 1004-1005 ◽  
pp. 1013-1016 ◽  
Author(s):  
Chang Yi Kong ◽  
Yuuki Shiratori ◽  
Takeshi Sako ◽  
Futoshi Iwata
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Supercritical Fluid ◽  
Large Scale ◽  
Scale Production ◽  
Graphene Oxides ◽  
Practical Applications ◽  
Green Approach ◽  
Large Scale Production ◽  
Reduced Graphene

A green method to synthesize the reduced graphene oxide using supercritical fluid has been developed, which is an environmentally friendly and efficient route. The reduced graphene oxide has been examined by X-ray diffraction, Raman spectroscopy. We have also studied the effects of reduction temperatures and supercritical fluids on the electrical properties of reduced graphene oxide. It was found that ethanol has higher reducing capability than CO2at all temperatures (200 - 400°C) examined in this study for graphene oxide reduction. As a result, reduced graphene oxide (6300 S/m) from supercritical ethanol treatment has 5 times as high conductivity as that from supercritical CO2treatment at the reduction temperature of 400°C. This green process is applicable for large scale production of reduced graphene oxides for various practical applications.

scholarly journals Sprayed Pyrolyzed ZnO Films with Nanoflake and Nanorod Morphologies and Their Photocatalytic Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Nora S. Portillo-Vélez ◽  
Monserrat Bizarro
Keyword(s):  
Photocatalytic Activity ◽  
Large Scale ◽  
Spray Pyrolysis Technique ◽  
Structural Characteristics ◽  
Zno Nanorods ◽  
Volume Ratio ◽  
Precursor Solution ◽  
Synthesis Process ◽  
Zno Films ◽  
Scale Production

There is an increasing interest on the application of ZnO nanorods in photocatalysis and many growth methods have been applied, in particular the spray pyrolysis technique which is attractive for large scale production. However it is interesting to know if the nanorod morphology is the best considering its photocatalytic activity, stability, and cost effectiveness compared to a nonoriented growth. In this work we present a systematic study of the effect of the precursor solution (type of salt, solvent, and concentration) on the morphology of sprayed ZnO films to obtain nanoflakes and nanorods without the use of surfactants or catalysts. The surface properties and structural characteristics of these types of films were investigated to elucidate which morphology is more favorable for photocatalytic applications. Wettability and photocatalytic experiments were carried out in the same conditions. After UV irradiation both morphologies became hydrophilic and achieved a dye discoloration efficiency higher than 90%; however, the nanoflake morphology provided the highest photocatalytic performance (99% dye discoloration) and stability and the lowest energy consumption during the synthesis process. The surface-to-volume ratio revealed that the nanoflake morphology is more adequate for photocatalytic water treatment applications and that the thin nanorods should be preferred over the large ones.

scholarly journals An Overview of the Photocatalytic Water Splitting over Suspended Particles

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 60
Author(s):  
Muhammad Amtiaz Nadeem ◽  
Mohd Adnan Khan ◽  
Ahmed Abdeslam Ziani ◽  
Hicham Idriss
Keyword(s):  
Water Splitting ◽  
Large Scale ◽  
Cost Effective ◽  
Synthetic Methods ◽  
Scale Production ◽  
Practical Applications ◽  
Co Catalysts ◽  
Large Scale Production ◽  
Cost Effective Method ◽  
Order Of Magnitude

The conversion of solar to chemical energy is one of the central processes considered in the emerging renewable energy economy. Hydrogen production from water splitting over particulate semiconductor catalysts has often been proposed as a simple and a cost-effective method for large-scale production. In this review, we summarize the basic concepts of the overall water splitting (in the absence of sacrificial agents) using particulate photocatalysts, with a focus on their synthetic methods and the role of the so-called “co-catalysts”. Then, a focus is then given on improving light absorption in which the Z-scheme concept and the overall system efficiency are discussed. A section on reactor design and cost of the overall technology is given, where the possibility of the different technologies to be deployed at a commercial scale and the considerable challenges ahead are discussed. To date, the highest reported efficiency of any of these systems is at least one order of magnitude lower than that deserving consideration for practical applications.

scholarly journals A general aerosol-assisted biosynthesis of functional bulk nanocomposites

2018 ◽  
Vol 6 (1) ◽  
pp. 64-73 ◽  
Author(s):  
Qing-Fang Guan ◽  
Zi-Meng Han ◽  
Tong-Tong Luo ◽  
Huai-Bin Yang ◽  
Hai-Wei Liang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Large Scale ◽  
Bulk Material ◽  
Cellulose Nanofibrils ◽  
High Strength ◽  
Building Blocks ◽  
Scale Production ◽  
Cellulose Nanofibril ◽  
Practical Applications ◽  
Wide Range

Abstract Although a variety of nanoparticles with better-than-bulk material performances can be synthesized, it remains a challenge to scale the extraordinary properties of individual nanoscale units to the macroscopic level for bulk nanostructured materials. Here, we report a general and scalable biosynthesis strategy that involves simultaneous growth of cellulose nanofibrils through microbial fermentation and co-deposition of various kinds of nanoscale building blocks (NBBs) through aerosol feeding on solid culture substrates. We employ this biosynthesis strategy to assemble a wide range of NBBs into cellulose nanofibril-based bulk nanocomposites. In particular, the biosynthesized carbon nanotubes/bacterial cellulose nanocomposites that consist of integrated 3D cellulose nanofibril networks simultaneously achieve an extremely high mechanical strength and electrical conductivity, and thus exhibit outstanding performance as high-strength lightweight electromagnetic interference shielding materials. The biosynthesis approach represents a general and efficient strategy for large-scale production of functional bulk nanocomposites with enhanced performances for practical applications. Industrial-scale production of these bulk nanocomposite materials for practical applications can be expected in the near future.

Preparation and Properties of Alkali Stimulated Geopolymer and its Application in Thermal Insulation Coating

2011 ◽  
Vol 233-235 ◽  
pp. 2443-2446 ◽  
Author(s):  
Liang Chen ◽  
Wei Han ◽  
Zhen Li ◽  
Tao Wei ◽  
Cheng Jing Xiao
Keyword(s):  
Thermal Insulation ◽  
Volume Ratio ◽  
Amorphous Structure ◽  
Insulation Material ◽  
X Ray Diffraction ◽  
Micro Structure ◽  
Surface Protection ◽  
X Ray ◽  
Insulation Coating ◽  
Promising Application

Geopolymer was prepared by Metakaolin (MK) stimulated by sodium silicate and sodium hydroxide. X-Ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize micro-structure of geopolymer and geopolymer based coating. A serial of reagents were added to modify the coating and a thermal insulation material was produced. It was revealed that MK has quasi-crystal structure and the produced geopolymers had amorphous structure. The surface of geopolymer based coating, as well as the compressive strength, adhesive strength with concrete, could be modified by adding a certain amount of silane coupling agent, mica powders and wollastonite. By mixing the asprepared geopolymer and hollow glass beads with a volume ratio of 4:1, a thermal inslation coating was produced, which had a promising application in the surface protection of hydropower dam.

scholarly journals Efficient Mercury Removal at Ultralow Metal Concentrations by Cysteine Functionalized Carbon-Coated Magnetite

2020 ◽  
Vol 10 (22) ◽  
pp. 8262
Author(s):  
Assadawoot Srikhaow ◽  
Teera Butburee ◽  
Weeraphat Pon-On ◽  
Toemsak Srikhirin ◽  
Kanchana Uraisin ◽  
...  
Keyword(s):  
Large Scale ◽  
Raw Materials ◽  
Aqueous Media ◽  
Contaminated Water ◽  
Scale Production ◽  
Efficient Removal ◽  
Metal Concentrations ◽  
Practical Applications ◽  
Large Scale Production ◽  
Carbon Coated

This work reports the preparation and utility of cysteine-functionalized carbon-coated Fe3O4 materials (Cys-C@Fe3O4) as efficient sorbents for remediation of Hg(II)-contaminated water. Efficient removal (90%) of Hg(II) from 1000 ppb aqueous solutions is possible, at very low Cys-C@Fe3O4 sorbent loadings (0.01 g sorbent per liter of Hg(II) solution). At low metal concentrations (5–100 ppb Hg(II)), where adsorption is typically slow, Hg(II) removal efficiencies of 94–99.4% were achievable, resulting in final Hg(II) levels of <1.0 ppb. From adsorption isotherms, the Hg(II) adsorption capacity for Cys-C@Fe3O4 is 94.33 mg g−1, around three times that of carbon-coated Fe3O4 material. The highest partition coefficient (PC) of 2312.5 mgg−1µM−1 was achieved at the initial Hg (II) concentration of 100 ppb, while significantly high PC values of 300 mgg−1µM−1 and above were also obtained in the ultralow concentration range (≤20 ppb). Cys-C@Fe3O4 exhibits excellent selectivity for Hg(II) when tested in the presence of Pb(II), Ni(II), and Cu(II) ions, is easily separable from aqueous media by application of an external magnet, and can be regenerated for three subsequent uses without compromising Hg(II) uptake. Derived from commercially available raw materials, it is highly possible to achieve large-scale production of the functional sorbent for practical applications.

scholarly journals Alumina-Doped Silica Aerogels for High-Temperature Thermal Insulation

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 122
Author(s):  
Yu Wu ◽  
Xiaodong Wang ◽  
Lin Liu ◽  
Ze Zhang ◽  
Jun Shen
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Thermal Insulation ◽  
Large Scale ◽  
Low Cost ◽  
Linear Shrinkage ◽  
Silica Aerogels ◽  
Hydroxyl Groups ◽  
Scale Production ◽  
Α Al2o3

In this study, we used two methods to prepare alumina-doped silica aerogels with the aim of increasing the thermal stability of silica aerogels. The first method was physical doping of α-Al2O3 nano powders, and the second method was to create a chemical compound via the co-precursor of TEOS and AlCl3·6H2O in different proportions. The shrinkage, chemical composition, and specific surface area (SSA) of samples after heating at different temperatures were analyzed. Our results show that the silicon hydroxyl groups of samples derived from AlCl3·6H2O gradually decreased and nearly disappeared after heating at 800 °C, which indicates the complete dehydration of the silicon hydroxyl. Thus, the samples exhibited a large linear shrinkage and decreased SSA after high-temperature heat treatment. By contrast, samples doped with α-Al2O3 powders retained abundant silicon hydroxyl groups, and the 6.1 wt.% α-Al2O3-doped sample exhibited the lowest linear shrinkage of 11% and the highest SSA of 1056 m2/g after heat treatment at 800 °C. The alumina-doped silica aerogels prepared using a simple and low-price synthesized method pave the way for the low-cost and large-scale production of high-temperature thermal insulation.

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