Aerogel Embedded High-performance Fibrous Materials

Kód výsledku v IS VaVaI

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RIV/46747885:24620/19:00006710

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Aerogel Embedded High-performance Fibrous Materials

Popis výsledku v původním jazyce

As conventional thermal insulators used in technical applications, nonwoven fabrics exhibit good thermal insulation ability. Their impact on thermal insulation performance is determined by the physical and structural parameters of fibrous structures. Especially, their thermal insulation ability strongly depends on the fabric thickness. Generally, the thermal insulating ability improves with the increase in fabric thickness. However, when this thickness is limited to a few milli-meters, the insulating performance is restricted. Thus, development of high-performance thermal insulation materials to save space and energy consumption, increase comfort, decrease cost and complexity has gain increasing attention. Nowadays, silica aerogel has been well acknowledged as one of the most attractive thermal insulating materials for applications in protective clothing, automotive industry, building and construction products. Recently, the successful and cost- effective production of silica aerogels by the use of inexpensive precursors and the ambient pressure drying method has been achieved, this raises the possibility of continuous production with lower operating costs for industrial application. Aerogel can be used as loose bulk material for thermal insulation, but for the majority of applications a bound form such as aerogel containing sheet is required. For this purpose, aerogels are usually incorporated into lightweight textile structure such as nonwoven fabric, with the assistance of binding material. Recently, combining nonwoven fabric with silica aerogel to enhance thermal insulation ability has gained increasing interest during the past several decades. A lot of experimental studies confirmed that the aerogel present in textile structure would significantly improve the overall thermal performance, however, the application of aerogel granules has so far been limited to a few methods such as coating, padding and impregnation. In these obtained aerogel-embedded materials, aerogel granules are exposed or filled into the void space of textile structure, the porous space of the loose textile structure is partly filled by additive agent, the thermal performance of the final product is thus reduced since the overall pore volume which is essential to entrap air pockets is decreased. Meanwhile, the nanopores of aerogel granules are filled or covered by binding materials, this would blunt their advantage in thermal insulation ability. Furthermore, the prepared materials may lack compression resilience, causing reduced recovery after exposure to external forces, which may influence the final use and the sustainability of thermal- insulating function. However, these problems were not considered in designing aerogel based fibrous materials. Moreover, existing works were mainly focused on pure fibrous materials in absolutely flat state with a simple airflow. There appears a gap in the study on the convective heat transfer through multi-component fibrous structure system or under more complicated condition. The materials could be used in building, piping and technical applications such as winter jacket, sleeping bag and glove in extreme weather, which are not always in absolutely flat state. However, there is sparse information available regarding natural and forced convection through aerogel-based nonwoven. Although numerical simulation has been applied to evaluate the heat flux, temperature distributions, and convective heat transfer coefficients of aerogel-embedded fibrous insulating materials, thermal performance of aerogel-based nonwoven under convection conditions is still not well understood.

Název v anglickém jazyce

Aerogel Embedded High-performance Fibrous Materials

Popis výsledku anglicky

As conventional thermal insulators used in technical applications, nonwoven fabrics exhibit good thermal insulation ability. Their impact on thermal insulation performance is determined by the physical and structural parameters of fibrous structures. Especially, their thermal insulation ability strongly depends on the fabric thickness. Generally, the thermal insulating ability improves with the increase in fabric thickness. However, when this thickness is limited to a few milli-meters, the insulating performance is restricted. Thus, development of high-performance thermal insulation materials to save space and energy consumption, increase comfort, decrease cost and complexity has gain increasing attention. Nowadays, silica aerogel has been well acknowledged as one of the most attractive thermal insulating materials for applications in protective clothing, automotive industry, building and construction products. Recently, the successful and cost- effective production of silica aerogels by the use of inexpensive precursors and the ambient pressure drying method has been achieved, this raises the possibility of continuous production with lower operating costs for industrial application. Aerogel can be used as loose bulk material for thermal insulation, but for the majority of applications a bound form such as aerogel containing sheet is required. For this purpose, aerogels are usually incorporated into lightweight textile structure such as nonwoven fabric, with the assistance of binding material. Recently, combining nonwoven fabric with silica aerogel to enhance thermal insulation ability has gained increasing interest during the past several decades. A lot of experimental studies confirmed that the aerogel present in textile structure would significantly improve the overall thermal performance, however, the application of aerogel granules has so far been limited to a few methods such as coating, padding and impregnation. In these obtained aerogel-embedded materials, aerogel granules are exposed or filled into the void space of textile structure, the porous space of the loose textile structure is partly filled by additive agent, the thermal performance of the final product is thus reduced since the overall pore volume which is essential to entrap air pockets is decreased. Meanwhile, the nanopores of aerogel granules are filled or covered by binding materials, this would blunt their advantage in thermal insulation ability. Furthermore, the prepared materials may lack compression resilience, causing reduced recovery after exposure to external forces, which may influence the final use and the sustainability of thermal- insulating function. However, these problems were not considered in designing aerogel based fibrous materials. Moreover, existing works were mainly focused on pure fibrous materials in absolutely flat state with a simple airflow. There appears a gap in the study on the convective heat transfer through multi-component fibrous structure system or under more complicated condition. The materials could be used in building, piping and technical applications such as winter jacket, sleeping bag and glove in extreme weather, which are not always in absolutely flat state. However, there is sparse information available regarding natural and forced convection through aerogel-based nonwoven. Although numerical simulation has been applied to evaluate the heat flux, temperature distributions, and convective heat transfer coefficients of aerogel-embedded fibrous insulating materials, thermal performance of aerogel-based nonwoven under convection conditions is still not well understood.

Druh

C - Kapitola v odborné knize

CEP obor

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OECD FORD obor

20503 - Textiles; including synthetic dyes, colours, fibres (nanoscale materials to be 2.10; biomaterials to be 2.9)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název knihy nebo sborníku

RECENT TRENDS IN FIBROUS MATERIAL SCIENCE

ISBN

978-80-7494-493-2

Počet stran výsledku

40

Strana od-do

94-133

Počet stran knihy

484

Název nakladatele

Technická univerzita v Liberci

Místo vydání

Liberec

Kód UT WoS kapitoly

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