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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    title = "Molecular simulation of flame retardancy: solid-phase effects of aluminium hydroxide",
    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",
    year = "2018",
    language = "English",
    note = "22nd International Symposium on Analytical and Applied Pyrolysis, Pyro2018 ; Conference date: 03-06-2018 Through 08-06-2018",
    url = "http://cec.ach.nitech.ac.jp/pyro2018/",

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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.