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CEAS Aeronautical Journal

, Volume 9, Issue 1, pp 235–248 | Cite as

Novel epoxy prepreg resins for aircraft interiors based on combinations of halogen-free flame retardants

  • Thomas Neumeyer
  • Anika Bauernfeind
  • Verena Eigner
  • Claudia Mueller
  • Kerstin Pramberger
  • Volker AltstaedtEmail author
Original Paper
  • 111 Downloads

Abstract

Heat release and smoke emission are crucial characteristics regarding the burning behaviour of materials used inside the cabin of a commercial aircraft. In this work, an approach to enhance these properties of epoxy novolac-based resin formulations is presented. The phosphorus-based flame retardant DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) is used in combination with inorganic flame retardants to merge different flame-retarding mechanisms. The effects of the single flame-retarding components on the fire behaviour of the neat epoxy resin are investigated at first by cone calorimeter measurements. Following, the interactions of combining (1) DOPO and ATH and (2) DOPO and boehmite are studied systematically. It is shown that the sole DOPO modification effectively reduces the heat release by gas phase mechanisms, but at the same time increases the smoke production tremendously due to the flame inhibition and the resulting incomplete combustion. By adding inorganic flame retardants, this increase in smoke release can be compensated for. Furthermore, the aforementioned combination of DOPO and ATH leads to a synergistic effect on time to ignition. Fire testing on sandwich structures, consisting of prepreg face sheets based on the resin systems described before, reveals that the relevant characteristics to meet fire safety requirements for aircraft interiors can be fulfilled. Additionally, the influence of the modifiers on the thermal and mechanical properties of the cured resins are presented and discussed. The inorganic flame retardants significantly increase the fracture toughness of the originally rather brittle epoxy novolac resins from around 0.5 MPa m1/2 up to approximately 0.8 MPa m1/2 for the boehmite type used and up to 1.0 MPa m1/2 for ATH at a filler loading of 33.3 wt% in both cases.

Keywords

Prepreg Epoxy Flame retardancy Halogen free Cone calorimetry 

Notes

Acknowledgements

The authors are grateful to the Federal Ministry for Economic Affairs and Energy for the financial support through LuFo and to the German Research Foundation (DFG) for support within the Collaborative Research Center 840 (SFB 840).

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Copyright information

© Deutsches Zentrum für Luft- und Raumfahrt e.V. 2018

Authors and Affiliations

  • Thomas Neumeyer
    • 1
  • Anika Bauernfeind
    • 1
  • Verena Eigner
    • 1
  • Claudia Mueller
    • 1
  • Kerstin Pramberger
    • 1
  • Volker Altstaedt
    • 1
    Email author
  1. 1.Department of Polymer EngineeringUniversity of BayreuthBayreuthGermany

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