Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide

Research output: Contribution to conferenceConference AbstractScientificpeer-review

Abstract

The key physical and chemical processes of fire retardancy are connected to the thermal decomposition of an organic polymer matrix and a fire retardant additive. Physical fire retardant compounds act through solid-phase mechanisms such as endothermic dissociation and thermal shielding, and gas-phase mechanisms such as dilution and radical quenching. Chemical fire retardants, on the other hand, modify the decomposition pathway to minimize the production of volatile fractions that would fuel flames. The bulk of our current understanding on fire retardant chemicals is qualitative. A wealth of empirical knowledge exists, but understanding on the level of modelling capability remains in its infancy.
We have carried out reactive molecular dynamics (RMD) simulations based on the ReaxFF reactive force field to demonstrate molecular simulation of the thermal decomposition of amorphous polyethylene (PE) and aluminium (tri)hydroxide (ATH). The simulations reproduce the well-known mechanisms of fire retardancy associated with ATH, namely endothermic decomposition to produce water and an alumina residue, and heat absorption effects due to the presence of the filler and its residue. In addition, the simulations reveal a chemical interaction in which hydrogen is abstracted from the polymer by ATH, resulting in enhanced water production and enhanced charring of the polymer.
Based on the results of this study, we consider RMD simulations a promising tool for investigating existing and emerging fire retardant concepts, and the pyrolysis chemistry of fire retardant polymer systems.
Original languageEnglish
Number of pages1
Publication statusPublished - 2018
MoE publication typeNot Eligible
Event22nd International Symposium on Analytical and Applied Pyrolysis - Clock Tower and International Science Innovation Building, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto, Japan
Duration: 3 Jun 20188 Jun 2018
http://cec.ach.nitech.ac.jp/pyro2018/

Conference

Conference22nd International Symposium on Analytical and Applied Pyrolysis
Abbreviated titlePyro2018
CountryJapan
CityKyoto
Period3/06/188/06/18
Internet address

Fingerprint

Hydrated alumina
Flame retardants
Pyrolysis
Aluminum
Molecular dynamics
Fires
Polymers
Heat shielding
Decomposition
Organic polymers
Computer simulation
Polymer matrix
Dilution
Polyethylenes
Fillers
Water
Quenching
Alumina
Hydrogen
Gases

Keywords

  • pyrolysis
  • reactive molecular dynamics
  • aluminium hydroxide

Cite this

Vaari, J., & Paajanen, A. (2018). Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide. Abstract from 22nd International Symposium on Analytical and Applied Pyrolysis, Kyoto, Japan.
Vaari, Jukka ; Paajanen, Antti. / Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide. Abstract from 22nd International Symposium on Analytical and Applied Pyrolysis, Kyoto, Japan.1 p.
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abstract = "The key physical and chemical processes of fire retardancy are connected to the thermal decomposition of an organic polymer matrix and a fire retardant additive. Physical fire retardant compounds act through solid-phase mechanisms such as endothermic dissociation and thermal shielding, and gas-phase mechanisms such as dilution and radical quenching. Chemical fire retardants, on the other hand, modify the decomposition pathway to minimize the production of volatile fractions that would fuel flames. The bulk of our current understanding on fire retardant chemicals is qualitative. A wealth of empirical knowledge exists, but understanding on the level of modelling capability remains in its infancy.We have carried out reactive molecular dynamics (RMD) simulations based on the ReaxFF reactive force field to demonstrate molecular simulation of the thermal decomposition of amorphous polyethylene (PE) and aluminium (tri)hydroxide (ATH). The simulations reproduce the well-known mechanisms of fire retardancy associated with ATH, namely endothermic decomposition to produce water and an alumina residue, and heat absorption effects due to the presence of the filler and its residue. In addition, the simulations reveal a chemical interaction in which hydrogen is abstracted from the polymer by ATH, resulting in enhanced water production and enhanced charring of the polymer.Based on the results of this study, we consider RMD simulations a promising tool for investigating existing and emerging fire retardant concepts, and the pyrolysis chemistry of fire retardant polymer systems.",
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author = "Jukka Vaari and Antti Paajanen",
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note = "22nd International Symposium on Analytical and Applied Pyrolysis, Pyro2018 ; Conference date: 03-06-2018 Through 08-06-2018",
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Vaari, J & Paajanen, A 2018, 'Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide' 22nd International Symposium on Analytical and Applied Pyrolysis, Kyoto, Japan, 3/06/18 - 8/06/18, .

Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide. / Vaari, Jukka; Paajanen, Antti.

2018. Abstract from 22nd International Symposium on Analytical and Applied Pyrolysis, Kyoto, Japan.

Research output: Contribution to conferenceConference AbstractScientificpeer-review

TY - CONF

T1 - Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide

AU - Vaari, Jukka

AU - Paajanen, Antti

PY - 2018

Y1 - 2018

N2 - The key physical and chemical processes of fire retardancy are connected to the thermal decomposition of an organic polymer matrix and a fire retardant additive. Physical fire retardant compounds act through solid-phase mechanisms such as endothermic dissociation and thermal shielding, and gas-phase mechanisms such as dilution and radical quenching. Chemical fire retardants, on the other hand, modify the decomposition pathway to minimize the production of volatile fractions that would fuel flames. The bulk of our current understanding on fire retardant chemicals is qualitative. A wealth of empirical knowledge exists, but understanding on the level of modelling capability remains in its infancy.We have carried out reactive molecular dynamics (RMD) simulations based on the ReaxFF reactive force field to demonstrate molecular simulation of the thermal decomposition of amorphous polyethylene (PE) and aluminium (tri)hydroxide (ATH). The simulations reproduce the well-known mechanisms of fire retardancy associated with ATH, namely endothermic decomposition to produce water and an alumina residue, and heat absorption effects due to the presence of the filler and its residue. In addition, the simulations reveal a chemical interaction in which hydrogen is abstracted from the polymer by ATH, resulting in enhanced water production and enhanced charring of the polymer.Based on the results of this study, we consider RMD simulations a promising tool for investigating existing and emerging fire retardant concepts, and the pyrolysis chemistry of fire retardant polymer systems.

AB - The key physical and chemical processes of fire retardancy are connected to the thermal decomposition of an organic polymer matrix and a fire retardant additive. Physical fire retardant compounds act through solid-phase mechanisms such as endothermic dissociation and thermal shielding, and gas-phase mechanisms such as dilution and radical quenching. Chemical fire retardants, on the other hand, modify the decomposition pathway to minimize the production of volatile fractions that would fuel flames. The bulk of our current understanding on fire retardant chemicals is qualitative. A wealth of empirical knowledge exists, but understanding on the level of modelling capability remains in its infancy.We have carried out reactive molecular dynamics (RMD) simulations based on the ReaxFF reactive force field to demonstrate molecular simulation of the thermal decomposition of amorphous polyethylene (PE) and aluminium (tri)hydroxide (ATH). The simulations reproduce the well-known mechanisms of fire retardancy associated with ATH, namely endothermic decomposition to produce water and an alumina residue, and heat absorption effects due to the presence of the filler and its residue. In addition, the simulations reveal a chemical interaction in which hydrogen is abstracted from the polymer by ATH, resulting in enhanced water production and enhanced charring of the polymer.Based on the results of this study, we consider RMD simulations a promising tool for investigating existing and emerging fire retardant concepts, and the pyrolysis chemistry of fire retardant polymer systems.

KW - pyrolysis

KW - reactive molecular dynamics

KW - aluminium hydroxide

M3 - Conference Abstract

ER -

Vaari J, Paajanen A. Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide. 2018. Abstract from 22nd International Symposium on Analytical and Applied Pyrolysis, Kyoto, Japan.