Commercial fire-retarded PET formulations - relationship between thermal degradation behaviour and fire-retardant action

John J. Liggat, Hélène A. Lecomte, University of Strathclyde (Funder)

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Many types of fire-retardants are used in poly(ethylene terephthalate), PET, formulations, and two commercial fire retardants, Ukanol(TM) and Phosgard(TM), have been shown to improve significantly PET flame-retardancy when used as comonomers. Phosgard incorporates a phosphorus atom within the main chain whereas Ukanol incorporates a phosphorus atom as a pendent substituent. Despite their acknowledged effectiveness, the mode of action of these fire retardants remains unclear, and in this paper we present a comparison of the overall thermal degradation behaviour of PET and Ukanol and Phosgard fire retarded formulations. DSC and particularly TGA data show that both Ukanol and Phosgard have some stabilising influence on PET degradation, especially under oxidative conditions. TGA and pyrolysis experiments both clearly indicate that neither additive acts as a char promoter. Only the Phosgard formulation shows any release of volatile phosphorus species which could act in the gas phase. On the other hand, the most striking feature of the pyrolysis experiments is the macroscopic structure of the chars produced by the fire-retarded formulations, which hints at their fire-retardancy action - an open-cell charred foam was obtained upon charring at 400°C or 600°C. This foaming layer between the degrading melt and the flame would lower the amount of fuel available for combustion, and would also limit the feedback of heat to the condensed phase.
LanguageEnglish
Pages498-506
Number of pages8
JournalPolymer Degradation and Stability
Volume93
Issue number2
DOIs
Publication statusPublished - 6 Nov 2007

Fingerprint

Flame Retardants
flame retardants
thermal degradation
Flame retardants
Phosphorus
Fires
Pyrolysis
phosphorus
formulations
pyrolysis
flames
Atoms
Polyethylene Terephthalates
charring
Polyethylene terephthalates
foaming
Foams
polyethylene terephthalate
Gases
Experiments

Keywords

  • PET
  • fire retardancy
  • thermal degradation
  • DSC
  • TGA
  • pyrolysis

Cite this

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title = "Commercial fire-retarded PET formulations - relationship between thermal degradation behaviour and fire-retardant action",
abstract = "Many types of fire-retardants are used in poly(ethylene terephthalate), PET, formulations, and two commercial fire retardants, Ukanol(TM) and Phosgard(TM), have been shown to improve significantly PET flame-retardancy when used as comonomers. Phosgard incorporates a phosphorus atom within the main chain whereas Ukanol incorporates a phosphorus atom as a pendent substituent. Despite their acknowledged effectiveness, the mode of action of these fire retardants remains unclear, and in this paper we present a comparison of the overall thermal degradation behaviour of PET and Ukanol and Phosgard fire retarded formulations. DSC and particularly TGA data show that both Ukanol and Phosgard have some stabilising influence on PET degradation, especially under oxidative conditions. TGA and pyrolysis experiments both clearly indicate that neither additive acts as a char promoter. Only the Phosgard formulation shows any release of volatile phosphorus species which could act in the gas phase. On the other hand, the most striking feature of the pyrolysis experiments is the macroscopic structure of the chars produced by the fire-retarded formulations, which hints at their fire-retardancy action - an open-cell charred foam was obtained upon charring at 400°C or 600°C. This foaming layer between the degrading melt and the flame would lower the amount of fuel available for combustion, and would also limit the feedback of heat to the condensed phase.",
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Commercial fire-retarded PET formulations - relationship between thermal degradation behaviour and fire-retardant action. / Liggat, John J.; Lecomte, Hélène A.; University of Strathclyde (Funder).

In: Polymer Degradation and Stability, Vol. 93, No. 2, 06.11.2007, p. 498-506.

Research output: Contribution to journalArticle

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AU - Liggat, John J.

AU - Lecomte, Hélène A.

AU - University of Strathclyde (Funder)

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