Enhancement of Mechanical and Thermal Characteristics of Polyurethane-Based Composite with Silica Aerogel

2019 ◽  
Vol 951 ◽  
pp. 63-67 ◽  
Author(s):  
Jae Hyeok Ahn ◽  
Jeong Hyeon Kim ◽  
Jeong Dae Kim ◽  
Seul Kee Kim ◽  
Kang Hyun Park ◽  
...  
Keyword(s):  
Silica Aerogel ◽  
Heat Insulation ◽  
Porous Silica ◽  
Thermal Characteristics ◽  
Weight Percent ◽  
Polyurethane Foams ◽  
Mechanical And Thermal Properties ◽  
Efficient Alternative ◽  
Insulation Performance ◽  
Compressive Tests

Synthesis of polyurethane foams (PUF) with silica aerogel nanoparticles is an efficient alternative to improve the mechanical and thermal properties of the foam owing to the outstanding thermal insulation properties of porous silica aerogel nanoparticles. Silica aerogel was added into polyurethane foams at different weight percent (0, 1, 3, 5 wt.%) to observe the changes in the material properties. To confirm the applicability of the synthesized PUF to the heat insulating material, compressive tests were carried out at ambient and cryogenic temperature (20, -163°C) and the thermal conductivities were measured according to wt.%. In addition, the cell microstructure was identified using FE-SEM to analyze the effect of silica aerogels on the foam morphologies. As a result of the experiment, it was confirmed that the mechanical strength and the heat insulation performance were improved in the polyurethane foam containing 1 wt.% of silica aerogel.

scholarly journals Microstructure and Thermal Insulation Property of Silica Composite Aerogel

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 993 ◽  
Author(s):  
Lei Shang ◽  
Yang Lyu ◽  
Wenbo Han
Keyword(s):  
Thermal Insulation ◽  
Silica Aerogel ◽  
Infrared Radiation ◽  
Performance Test ◽  
Heat Insulation ◽  
Insulation Material ◽  
Cold Surface ◽  
Composite Aerogel ◽  
Aerogel Composite ◽  
Insulation Performance

Tetraethyl orthosilicate was selected as a matrix of heat insulating materials among three silanes, and an anti-infrared radiation fiber was chosen as a reinforcement for silica aerogel insulation composite. The silica aerogel was combined well and evenly distributed in the anti-infrared radiation fiber. The heat insulation effect was improved with the increase in thickness of the aerogel insulation material, as determined by the self-made aerospace insulation material insulation performance test equipment. The 15 mm and 30 mm thick thermal insulation material heated at 250 °C for 3 h, the temperatures at the cold surface were about 80 °C and 60 °C, respectively, and the temperatures at 150 mm above the cold surface were less than 60 °C and 50 °C, respectively. The silica aerogel composites with various thicknesses showed good thermal insulation stability. The silica insulation composite with a thickness of 15 mm exhibited good heat insulation performance, meets the thermal insulation requirements of general equipment compartments under low-temperature and long-term environmental conditions. The thermal conductivity of prepared silica aerogel composite was 0.0191 W·m−1·k−1 at room temperature and 0.0489 W·m−1·k−1 at 500 °C.

scholarly journals Influence of Silica-Aerogel on Mechanical Characteristics of Polyurethane-Based Composites: Thermal Conductivity and Strength

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1790
Author(s):  
Jeong-Hyeon Kim ◽  
Jae-Hyeok Ahn ◽  
Jeong-Dae Kim ◽  
Dong-Ha Lee ◽  
Seul-Kee Kim ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Cell Morphology ◽  
Environmental Conditions ◽  
Silica Aerogel ◽  
Porous Silica ◽  
Mechanical And Thermal Properties ◽  
Insulation Material ◽  
Wide Range ◽  
Insulation Systems

Polyurethane foam (PUF) has generally been used in liquefied natural gas (LNG) carrier cargo containment systems (CCSs) owing to its excellent mechanical and thermal properties over a wide range of temperatures. An LNG CCS must be designed to withstand extreme environmental conditions. However, as the insulation material for LNGC CCSs, PUF has two major limitations: its strength and thermal conductivity. In the present study, PUFs were synthesized with various weight percentages of porous silica aerogel to reinforce the characteristics of PUF used in LNG carrier insulation systems. To evaluate the mechanical strength of the PUF-silica aerogel composites considering LNG loading/unloading environmental conditions, compressive tests were conducted at room temperature (20 °C) and a cryogenic temperature (−163 °C). In addition, the thermal insulation performance and cellular structure were identified to analyze the effects of silica aerogels on cell morphology. The cell morphology of PUF-silica aerogel composites was relatively homogeneous, and the cell shape remained closed at 1 wt.% in comparison to the other concentrations. As a result, the mechanical and thermal properties were significantly improved by the addition of 1 wt.% silica aerogel to the PUF. The mechanical properties were reduced by increasing the silica aerogel content to 3 wt.% and 5 wt.%, mainly because of the pores generated on the surface of the composites.

scholarly journals Influence of Far Infrared TiO2 and Multi-Walled Carbon Nanotubes Coatings on the Performance of a Hot Water Heater

2021 ◽  
Vol 11 (15) ◽  
pp. 7043
Author(s):  
Tun-Ping Teng ◽  
Shang-Pang Yu ◽  
Yeou-Feng Lue ◽  
Qi-Lin Xie ◽  
Hsiang-Kai Hsieh ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Heating Rate ◽  
Heat Insulation ◽  
Far Infrared ◽  
Hot Water ◽  
Insulation Material ◽  
Water Heater ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Insulation Performance

This study selects titanium dioxide (TiO2) and multi-walled carbon nanotubes (MWCNTs) as far-infrared materials (FIRMs), and further adds water-based acrylic coatings to prepare far-infrared coatings (FIRCs). FIRCs are uniformly coated on #304 stainless steel sheets to make the test samples, which are then installed between the shell and insulation material of the hot water heater to measure the influences of various FIRCs on the performance of the hot water heater. The research results show no significant difference in the heating rate or heat insulation performance of the hot water heater with or without FIRCs coating. However, the uniformity of the water temperatures of the test samples is significantly improved with FIRCs. Considering that the uniformity of water temperature will inhibit the heating rate and heat insulation performance of the hot water heater, TiO2-FIRC should provide better performance improvement when applied to the hot water heater in this study. The application of TiO2-FIRC to large-scale hot water heaters with a high aspect ratio will effectively improve the quality of hot water supply in the future.

Bio-based Polyurethane-clay Nanocomposite Foams: Systheses and Properties

2009 ◽  
Vol 1188 ◽  
Author(s):  
Min Liu ◽  
Zoran S. Petrovic ◽  
Yijin Xu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Cell Structure ◽  
Polyurethane Foams ◽  
Mechanical And Thermal Properties ◽  
Cell Content ◽  
Modified Clay ◽  
Rigid Polyurethane Foams ◽  
Nanocomposite Foams ◽  
Organically Modified

AbstractStarting from a bio-based polyol through modification of soybean oil, BIOH™ X-210, two series of bio-based polyurethanes-clay nanocomposite foams have been prepared. The effects of organically-modified clay types and loadings on foam morphology, cell structure, and the mechanical and thermal properties of these bio-based polyurethanes-clay nanocomposite foams have been studied with optical microscopy, compression test, thermal conductivity, DMA and TGA characterization. Density of nanocomposite foams decreases with the increase of clay loadings, while reduced 10% compressive stress and yield stress keep constant up to 2.5% clay loading in polyol. The friability of rigid polyurethane-clay nanocomposite foams is high than that of foam without clay, and the friability for nanofoams from Cloisite® 10A is higher than that from 30B at the same clay loadings. The incorporation of clay nanoplatelets decreases the cell size in nanocomposite foams, meanwhile increases the cell density; which would be helpful in terms of improving thermal insulation properties. All the nanocomposite foams were characterized by increased closed cell content compared with the control foam from X-210 without clay, suggesting the potential to improve thermal insulation of rigid polyurethane foams by utilizing organically modified clay. Incorporation of clay into rigid polyurethane foams results in the increase in glass transition temperature: the Tg increased from 186 to 197 to 204 °C when 30B concentration in X-210 increased from 0 to 0.5 to 2.5%, respectively. Even though the thermal conductivity of nanocomposite foams from 30B is lower than or equal to that of rigid polyurethane control foam from X-210, thermal conductivity of nanocomposite foams from 10A is higher than that of control at all 10A concentrations. The reason for this abnormal phenomenon is not clear at this moment; investigation on this is on progress.

Optical Characterization of Silica Aerogel

1988 ◽  
Vol 121 ◽  
Author(s):  
Lawrence W. Hrubesh ◽  
Cynthia T. Alviso
Keyword(s):  
Silica Aerogel ◽  
Porous Silica ◽  
Optical Characterization ◽  
Optical Methods ◽  
Gradient Index ◽  
Two Dimensional ◽  
Two Dimensional Image ◽  
The Third ◽  
Third Dimension

ABSTRACTTwo optical methods are described for mapping the local variations of refractive index within monoliths of porous silica aerogel. One is an interferometrie measurement that produces “iso-index” fringes in a two dimensional image; an orthogonal view gives the third dimension information. The other method uses the deflection of a He-Ne laser beam to map the gradient index within a sample. The quantification of the measurements is described and the accuracy of the results is discussed.

Mechanical and thermal properties of nanofibrillated cellulose reinforced silica aerogel composites

2015 ◽  
Vol 217 ◽  
pp. 150-158 ◽  
Author(s):  
Joanna C.H. Wong ◽  
Hicret Kaymak ◽  
Philippe Tingaut ◽  
Samuel Brunner ◽  
Matthias M. Koebel
Keyword(s):  
Thermal Properties ◽  
Silica Aerogel ◽  
Nanofibrillated Cellulose ◽  
Mechanical And Thermal Properties

Research on Heat Transfer Characteristics of Nano-Porous Silica Aerogel Material and its Application on Mars Surface Mission

2014 ◽  
Vol 924 ◽  
pp. 329-335 ◽  
Author(s):  
Cong Hang Li ◽  
Shi Chen Jiang ◽  
Zheng Ping Yao ◽  
Song Sheng ◽  
Xin Jian Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Silica Aerogel ◽  
Thermal Environment ◽  
Porous Silica ◽  
Heat Transfer Model ◽  
Heat Radiation ◽  
Transfer Model ◽  
Ambient Conditions ◽  
Coupled Heat Transfer

Based on the nanoporous network structure features of silica aerogel, the gas-solid coupled heat transfer model of silica aerogel is analyzed, and the calculation formulas of the gas-solid coupled, the gas thermal conductivity and the heat radiation within the aerogel are derived. The thermal conductivity of pure silica aerogel is calculated according to the derived heat transfer model and is also experimentally measured. Moreover, measurements on the thermal conductivities of silica aerogel composites with different densities at ambient conditions are performed. And finally, a novel design of silica aerogel based integrated structure and thermal insulation used for withstanding the harsh thermal environment on the Martin surface is presented.

Preparation and Characterization of CCCW/Foamed Concrete Composite

2011 ◽  
Vol 261-263 ◽  
pp. 13-18
Author(s):  
Ke Qing Li ◽  
De Ping Chen ◽  
Shi Li Zhang ◽  
Bao Shun Liu
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Heat Insulation ◽  
High Humidity ◽  
Underground Engineering ◽  
New Approach ◽  
Foamed Concrete ◽  
Insulation Performance

Aimed at improving the waterproofing property of foamed concrete, a heat-insulating and waterproofing composite applied in underground engineering was prepared by using cementitious capillary crystalline waterproofing material and foamed concrete. The properties of foamed concrete and composite such as compressive strength, water absorption and thermal conductivity were tested and contrasted, and the compounding reaction mechanism was analyzed. The results show that, compared with foamed concrete, the water absorption of composite has been significantly reduced while the heat-insulating property of foamed concrete is maintained and the overall waterproofing and heat-insulation performance has been significantly improved. A new approach solving underground heat-harm such as high temperature and high humidity is provided.

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