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Flame retardancy of different‐sized expandable graphite particles for high‐density rigid polyurethane foams
Author(s) -
Shi Lei,
Li ZhongMing,
Xie BangHu,
Wang JianHua,
Tian ChunRong,
Yang MingBo
Publication year - 2006
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2021
Subject(s) - fire retardant , char , polyurethane , materials science , thermogravimetric analysis , composite material , thermal stability , graphite , particle size , particle (ecology) , pyrolysis , chemical engineering , oceanography , engineering , geology
Abstract The effects of expandable graphite (EG) of different particle sizes, on the fire‐retardant properties of high‐density rigid polyurethane foam (RPUF) (0.45 g cm −3 ) were studied. Samples of EG with different particle sizes were obtained by pulverization in an ultra‐high‐speed mixer for 4 and 13 min, respectively. It was shown that as received (EG0) and 4 min pulverized EG (EG4) efficiently improved the fire‐retardant properties of RPUF composites, while 13 min pulverized EG (EG13) did not. The char of the burned composites filled with EG0 and EG4 covered the whole surface of the samples and formed a complete physical barrier. This barrier material prevented combustible gases from feeding the flame and also isolated oxygen efficiently from the burning material. EG13 did not produce enough char to cover the whole surface of the burning sample, resulting in poor fire‐retardant property of the RPUF composites. Thermal degradation tests of the foams by thermogravimetric analysis indicated that EG showed negligible effects on the thermal stability of the RPUFs. Copyright © 2006 Society of Chemical Industry