東華大學圖書館 |

Characterizing Trends Between Surfactant Structure, Fuel Transport Through a Foam Layer, and Foam Fire Extinction Performance for Firefighting Foams Containing Novel Environmentally-Friendly Surfactants.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Characterizing Trends Between Surfactant Structure, Fuel Transport Through a Foam Layer, and Foam Fire Extinction Performance for Firefighting Foams Containing Novel Environmentally-Friendly Surfactants./
Author:	Hinnant, Katherine.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
Description:	307 p.
Notes:	Source: Dissertations Abstracts International, Volume: 82-12, Section: B.
Contained By:	Dissertations Abstracts International82-12B.
Subject:	Physical chemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28412779
ISBN:	9798738638657

Characterizing Trends Between Surfactant Structure, Fuel Transport Through a Foam Layer, and Foam Fire Extinction Performance for Firefighting Foams Containing Novel Environmentally-Friendly Surfactants.
Hinnant, Katherine.

Characterizing Trends Between Surfactant Structure, Fuel Transport Through a Foam Layer, and Foam Fire Extinction Performance for Firefighting Foams Containing Novel Environmentally-Friendly Surfactants. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 307 p.

Source: Dissertations Abstracts International, Volume: 82-12, Section: B.

Thesis (Ph.D.)--The George Washington University, 2021.

This item must not be sold to any third party vendors.

Fuel pool fires are extinguished using foam that floats between the fuel/flame interface, smothering the fire. Current firefighting foams contain fluorinated surfactants that rapidly suppress fires, but are environmentally harmful. An environmentally-friendly alternative must be found with matched extinction performance to ensure safety and survivability during dangerous fuel pool fires.Without a clear mechanistic understanding of how surfactant structure impacts fire suppression, it is difficult to identify environmentally-friendly alternatives for firefighting foams. Surfactants affect solution and foam properties, as well as mechanisms of foam/fire suppression. We hypothesize that fuel transport through the foam layer is an important mechanism for foam/fire suppression. Surfactant structure can affect diffusion of fuel through foam which may impact extinction performance. This work aimed to better understand foam/fire extinction mechanisms and to quantify the relationship between fuel diffusion through the foam and fire extinction. A CO2 laser-based extinction measurement was designed to characterize foam suppression in the flame environment at timescales before fire extinction. To quantify fuel transport through a foam layer, we designed an experiment to measure fuel flux and foam height with time. A model based on unsteady-state diffusion was then used to fit the data for an effective diffusion coefficient between the fuel and foam. We assessed a variety of solutions that contained individual surfactants, surfactant mixtures, and hydrotropes as an additive. These variations resulted in a range of properties and firefighting performance, allowing us to develop trends between measured values and extinction time. Six siloxane surfactants were evaluated individually and in a mixture with an alkylpolyglycoside surfactant. Synergism between siloxane and alkylpolyglycoside surfactants resulted in fluorine-free foams extinguishing a 19 cm heptane pool fire in 36 and 23 s while a fluorinated foam extinguished the fire in 16 s. However, synergism in fuel transport through the foam layer and in other solution properties was not observed. Multi-linear regression (MLR) models were developed using measured parameters and fire extinction performance. The models showed poor correlation, thus additional descriptors and statistical approaches should be tested to determine model limitations and improve future correlations. At present, our models suggest that fuel transport through the foam layer does not correlate with extinction ability or speed. Acute aquatic toxicity and the bioconcentration factor (BCF) of the surfactants in this study were estimated using Quantitative Structure Property Relationships (QSPRs). Trisiloxane structures were found to be more toxic to aquatic species and had higher BCF values than alkylpolyglycoside structures, but estimates for both were below standards set forth in the Safe Green Chemicals List. We were unable to estimate toxicity for mixtures which must be addressed: it's possible that synergistic effects observed during fire extinction may also result in synergism in mixture toxicity. While our hypothesis relating fuel transport through foam and fire extinction was incorrect, the extinction differences between different surfactant containing foams point to a clear relationship between structure and extinction. We must explore and identify other mechanisms that trend with extinction to shorten the knowledge gap between extinction and structure. This information can then be used to optimize surfactant structure for rapid fire suppression.

ISBN: 9798738638657Subjects--Topical Terms:

1981412
Physical chemistry.
Subjects--Index Terms:

Diffusion

Characterizing Trends Between Surfactant Structure, Fuel Transport Through a Foam Layer, and Foam Fire Extinction Performance for Firefighting Foams Containing Novel Environmentally-Friendly Surfactants.
LDR:04920nmm a2200373 4500 001 2346386
005 20230315102156.5
006 m o d
007 cr#unu||||||||
008 241004s2021 ||||||||||||||||| ||eng d
020 $a 9798738638657
035 $a (MiAaPQ)AAI28412779
035 $a AAI28412779
040 $a MiAaPQ $c MiAaPQ
100 1 $a Hinnant, Katherine. $0 (orcid)0000-0003-0745-2950 $3 3685472
245 1 0 $a Characterizing Trends Between Surfactant Structure, Fuel Transport Through a Foam Layer, and Foam Fire Extinction Performance for Firefighting Foams Containing Novel Environmentally-Friendly Surfactants.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2021
300 $a 307 p.
500 $a Source: Dissertations Abstracts International, Volume: 82-12, Section: B.
500 $a Advisor: Miller, J. Houston.
502 $a Thesis (Ph.D.)--The George Washington University, 2021.
506 $a This item must not be sold to any third party vendors.
520 $a Fuel pool fires are extinguished using foam that floats between the fuel/flame interface, smothering the fire. Current firefighting foams contain fluorinated surfactants that rapidly suppress fires, but are environmentally harmful. An environmentally-friendly alternative must be found with matched extinction performance to ensure safety and survivability during dangerous fuel pool fires.Without a clear mechanistic understanding of how surfactant structure impacts fire suppression, it is difficult to identify environmentally-friendly alternatives for firefighting foams. Surfactants affect solution and foam properties, as well as mechanisms of foam/fire suppression. We hypothesize that fuel transport through the foam layer is an important mechanism for foam/fire suppression. Surfactant structure can affect diffusion of fuel through foam which may impact extinction performance. This work aimed to better understand foam/fire extinction mechanisms and to quantify the relationship between fuel diffusion through the foam and fire extinction. A CO2 laser-based extinction measurement was designed to characterize foam suppression in the flame environment at timescales before fire extinction. To quantify fuel transport through a foam layer, we designed an experiment to measure fuel flux and foam height with time. A model based on unsteady-state diffusion was then used to fit the data for an effective diffusion coefficient between the fuel and foam. We assessed a variety of solutions that contained individual surfactants, surfactant mixtures, and hydrotropes as an additive. These variations resulted in a range of properties and firefighting performance, allowing us to develop trends between measured values and extinction time. Six siloxane surfactants were evaluated individually and in a mixture with an alkylpolyglycoside surfactant. Synergism between siloxane and alkylpolyglycoside surfactants resulted in fluorine-free foams extinguishing a 19 cm heptane pool fire in 36 and 23 s while a fluorinated foam extinguished the fire in 16 s. However, synergism in fuel transport through the foam layer and in other solution properties was not observed. Multi-linear regression (MLR) models were developed using measured parameters and fire extinction performance. The models showed poor correlation, thus additional descriptors and statistical approaches should be tested to determine model limitations and improve future correlations. At present, our models suggest that fuel transport through the foam layer does not correlate with extinction ability or speed. Acute aquatic toxicity and the bioconcentration factor (BCF) of the surfactants in this study were estimated using Quantitative Structure Property Relationships (QSPRs). Trisiloxane structures were found to be more toxic to aquatic species and had higher BCF values than alkylpolyglycoside structures, but estimates for both were below standards set forth in the Safe Green Chemicals List. We were unable to estimate toxicity for mixtures which must be addressed: it's possible that synergistic effects observed during fire extinction may also result in synergism in mixture toxicity. While our hypothesis relating fuel transport through foam and fire extinction was incorrect, the extinction differences between different surfactant containing foams point to a clear relationship between structure and extinction. We must explore and identify other mechanisms that trend with extinction to shorten the knowledge gap between extinction and structure. This information can then be used to optimize surfactant structure for rapid fire suppression.
590 $a School code: 0075.
650 4 $a Physical chemistry. $3 1981412
653 $a Diffusion
653 $a Fire suppression
653 $a Siloxane
653 $a Spectroscopy
653 $a Surfactants
690 $a 0494
710 2 $a The George Washington University. $b Chemistry. $3 1030692
773 0 $t Dissertations Abstracts International $g 82-12B.
790 $a 0075
791 $a Ph.D.
792 $a 2021
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28412779