Synergy effects of wood flour and fire retardants in flammability of wood-plastic composites

Toshikazu Umemura*, Yoshihiko Arao, Sakae Nakamura, Yuta Tomita, Tatsuya Tanaka

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

37 Citations (Scopus)


Addition of wood flour improve the mechanical properties of thermoplastics, on the other hand it increases the burning speed of the materials. To modify the flammability of wood-plastic composites(WPC), various fire retardants, such as ammonium polysphosphate (APP), melamine polyphosphate (MPP) and aluminum hydroxide were added to WPCs. Burning tests based on UL94 and cone calorimetry were conducted to evaluate a fire performance of WPCs with fire retardants. The addition of fire retardants could lead to self-extinguishing materials when 10 wt% of APP was used. However, in the case of pure polypropylene, addition of 10 wt% of APP did not improve the flammability. Wood flour accelerates the burning behavior of PP, but it can reduce the use of APP to achieve self-extinguishing materials. Synergy effects between wood flour and APP was confirmed. Wood flour facilitates the forming of foamed char layer by APP during the combustion. This protective char surface can reduce the heat and oxygen diffusion toward the WPCs. The effect of fire retardants of mechanical properties of WPCs was also investigated. Tensile strength and modulus of composites decreased with addition of fire retardants.

Original languageEnglish
Pages (from-to)48-56
Number of pages9
JournalEnergy Procedia
Issue numberC
Publication statusPublished - 2014
Externally publishedYes
EventEco-Energy and Materials Science and Engineering, EMSES 2014 - Phuket, Thailand
Duration: 2013 Dec 182013 Dec 21


  • Fire retardants
  • Flammability
  • Heat release rate
  • Wood-plastic composite

ASJC Scopus subject areas

  • General Energy


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