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The synergistic flame‐retardant behaviors of pentaerythritol phosphate and expandable graphite in rigid polyurethane foams
Author(s) -
Wang Shijun,
Qian Lijun,
Xin Fei
Publication year - 2018
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.23939
Subject(s) - pentaerythritol , fire retardant , materials science , polyurethane , limiting oxygen index , graphite , char , composite material , cone calorimeter , combustion , scanning electron microscope , chemical engineering , intumescent , organic chemistry , chemistry , engineering
The flame‐retardant rigid polyurethane foams (RPUFs) containing pentaerythritol phosphate (PEPA) and expandable graphite (EG) were prepared by box‐foaming. The flame retardancy of RPUFs was characterized using the limiting oxygen index (LOI) and cone calorimeter. The results show that the PEPA/EG system can effectively enhance the LOI values and reduce the peak release rate of RPUFs comparing with the foams only containing PEPA or EG although the flame retardants in all the samples are same proportion. The two results imply that the PEPA/EG system form flame‐retardant synergistic effect. The micromorphology and chemical structure of residues of RPUFs were also investigated by scanning electron microscope and Fourier transform‐infrared instruments. During combustion, the polyphosphates and their related analogues generated by PEPA can combine with the surfaces of expanded graphite, thereby resulting in the formation of the improved char layer. The layer possessed increased barrier effect and thereby imposing the better flame retardancy to RPUFs. POLYM. COMPOS., 39:329–336, 2018. © 2016 Society of Plastics Engineers