Material-scale flammability characteristics of epoxy-based coating systems

Flammability of intumescent coatings at the materials-scale is “expected” to have an impact on their fire resistance offered to the steel member. However, to what extent and at what stage during the exposure to an imposed fire curve in a furnace are not thoroughly established. The role of different...

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Main Authors: Siow, Jonathan, Dasari, Aravind
Other Authors: School of Materials Science and Engineering
Format: Article
Language:English
Published: 2023
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Online Access:https://hdl.handle.net/10356/170413
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1704132023-09-12T00:49:58Z Material-scale flammability characteristics of epoxy-based coating systems Siow, Jonathan Dasari, Aravind School of Materials Science and Engineering Engineering::Materials Epoxy Fire Curves Flammability of intumescent coatings at the materials-scale is “expected” to have an impact on their fire resistance offered to the steel member. However, to what extent and at what stage during the exposure to an imposed fire curve in a furnace are not thoroughly established. The role of different functionality of the flame-retardant additives in this process is also not clear despite a thorough understanding of their thermal decomposition mechanisms. In an effort to better understand some of these aspects, in this work, model systems based on different flame-retardant additives in epoxy are chosen to cover various strategies (like intumescent, radical quenching, and endothermic behavior) that are typically employed to reduce the flammability of a coating system. The flame-retardant additives chosen are ammonium polyphosphate, tetrabromobisphenol-A, 9,10-dihydro-9-oxa-10-phosphaphenanthrene oxide, and aluminum trihydroxide. The effects of flame-retardant additives on the curing, thermal decomposition, and flammability of epoxy resin are investigated. Reactive flame-retardant additives, in particular, are found to reduce the enthalpy associated with curing of epoxy by more than 45%. However, as the amount of hardener incorporated in these formulations is not controlled despite the presence of reactive flame-retardant additives, this had a negative effect on the thermal decomposition behavior of the epoxy/flame-retardant formulations, and consequently on the calculated decomposition activation energies. Heating rate seems to be a dominating parameter influencing the flammability of the formulations. Peak heat release rate values, irrespective of the formulation, increased by more than 1382%–1970% by changing the heating rate in a pyrolysis flow combustion calorimeter from 6°C/min to 100°C/min. As the flammable volatiles released per unit time are higher at high heating rates, ignition and subsequent flaming of the coating occurred in the furnace tests, where a cellulosic fire curve was simulated. This has significantly influenced the fire resistance times. The authors acknowledge the support of JTC Corporation for supporting projects that deal with fire-retardant coatings through NTU-JTC Industrial Innovation Center. 2023-09-12T00:49:58Z 2023-09-12T00:49:58Z 2022 Journal Article Siow, J. & Dasari, A. (2022). Material-scale flammability characteristics of epoxy-based coating systems. Journal of Fire Sciences, 40(3), 194-213. https://dx.doi.org/10.1177/07349041221085898 0734-9041 https://hdl.handle.net/10356/170413 10.1177/07349041221085898 2-s2.0-85127316761 3 40 194 213 en RCA 17/365 Journal of Fire Sciences © 2022 The Author(s). All rights reserved.
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Materials
Epoxy
Fire Curves
spellingShingle Engineering::Materials
Epoxy
Fire Curves
Siow, Jonathan
Dasari, Aravind
Material-scale flammability characteristics of epoxy-based coating systems
description Flammability of intumescent coatings at the materials-scale is “expected” to have an impact on their fire resistance offered to the steel member. However, to what extent and at what stage during the exposure to an imposed fire curve in a furnace are not thoroughly established. The role of different functionality of the flame-retardant additives in this process is also not clear despite a thorough understanding of their thermal decomposition mechanisms. In an effort to better understand some of these aspects, in this work, model systems based on different flame-retardant additives in epoxy are chosen to cover various strategies (like intumescent, radical quenching, and endothermic behavior) that are typically employed to reduce the flammability of a coating system. The flame-retardant additives chosen are ammonium polyphosphate, tetrabromobisphenol-A, 9,10-dihydro-9-oxa-10-phosphaphenanthrene oxide, and aluminum trihydroxide. The effects of flame-retardant additives on the curing, thermal decomposition, and flammability of epoxy resin are investigated. Reactive flame-retardant additives, in particular, are found to reduce the enthalpy associated with curing of epoxy by more than 45%. However, as the amount of hardener incorporated in these formulations is not controlled despite the presence of reactive flame-retardant additives, this had a negative effect on the thermal decomposition behavior of the epoxy/flame-retardant formulations, and consequently on the calculated decomposition activation energies. Heating rate seems to be a dominating parameter influencing the flammability of the formulations. Peak heat release rate values, irrespective of the formulation, increased by more than 1382%–1970% by changing the heating rate in a pyrolysis flow combustion calorimeter from 6°C/min to 100°C/min. As the flammable volatiles released per unit time are higher at high heating rates, ignition and subsequent flaming of the coating occurred in the furnace tests, where a cellulosic fire curve was simulated. This has significantly influenced the fire resistance times.
author2 School of Materials Science and Engineering
author_facet School of Materials Science and Engineering
Siow, Jonathan
Dasari, Aravind
format Article
author Siow, Jonathan
Dasari, Aravind
author_sort Siow, Jonathan
title Material-scale flammability characteristics of epoxy-based coating systems
title_short Material-scale flammability characteristics of epoxy-based coating systems
title_full Material-scale flammability characteristics of epoxy-based coating systems
title_fullStr Material-scale flammability characteristics of epoxy-based coating systems
title_full_unstemmed Material-scale flammability characteristics of epoxy-based coating systems
title_sort material-scale flammability characteristics of epoxy-based coating systems
publishDate 2023
url https://hdl.handle.net/10356/170413
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