Toward an understanding of how red phosphorus and expandable graphite enhance the fire resistance of expandable polystyrene foams

Wenfei Ji, Yuan Yao, Jia Guo, Bin Fei, Xiaoyu Gu, Hongfei Li, Jun Sun, Sheng Zhang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


Flame retardant expandable polystyrene (EPS) foams were prepared by coating method. Red phosphorus (RP) and expandable graphite (EG) were chosen as the flame retardants to be coated on the surface of expanded PS beads. By the presence of 33 phr RP/EG with a mass ratio of 1:1, the limiting oxygen index of EPS foam could reach up to 26.9%, with V-0 rating obtained in UL-94 test. The peak heat release rate could also decrease to 180.67 kW/m2, which was 72.9% lower than that of neat EPS sample. Thermogravimetric analysis revealed an obvious increase of thermal stability and residue char amount by the presence of RP and EG. From the observation and analysis of char residue, it could be proposed that there existed a significant synergistic effect between RP and EG. RP could be oxidized and further react with graphite by the presence of oxygen at high temperature, forming isolated char layer and releasing nonflammable gases. Moreover, P radicals were generated at high temperature and could capture the radicals formed during the combustion of polystyrene and eliminate the burning chain reactions.

Original languageEnglish
Article number49045
JournalJournal of Applied Polymer Science
Issue number35
Publication statusPublished - 15 Sep 2020


  • flame retardance
  • foams
  • polystyrene

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry

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