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Expandable graphite‐methyl methacrylate‐acrylic acid copolymer composite particles as a flame retardant of rigid polyurethane foam
Author(s) -
Zhang XiaoGuang,
Ge LanLan,
Zhang WeiQin,
Tang JianHua,
Ye Ling,
Li ZhongMing
Publication year - 2011
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.34198
Subject(s) - materials science , polyurethane , composite material , thermogravimetric analysis , fire retardant , limiting oxygen index , composite number , methyl methacrylate , dynamic mechanical analysis , fourier transform infrared spectroscopy , methacrylate , emulsion polymerization , copolymer , polymer , polymer chemistry , chemical engineering , pyrolysis , char , engineering
Abstract An emulsion polymerization method was employed to prepare pulverized expandable graphite (pEG)‐poly(methyl methacrylate‐acrylic acid) copolymer [(PMA)] composite particles, and then the pEG‐P(MA) particles were used for a flame retardant of the rigid polyurethane foam (RPUF). Fourier transform infrared (FTIR) spectroscopy data demonstrated the existence of P(MA) in the pEG‐P(MA) particles, and the result of the thermogravimetric analysis (TGA) indicated that the content of P(MA) was 24.3 wt %. Morphological observation showed that the pEG particles were encapsulated by a layer of polymer coating to form typical core–shell composite particles. Due to the possible reaction between COOH of pEG‐P(MA) and R ‐CNO of isocyanate, the compatibility between the composite particles and the RPUF matrix was highly enhanced. In contrast to the pEG, the limiting oxygen index (LOI), the horizontal and vertical burning tests showed the pEG‐P(MA) composite particles could improve the flame retardancy effectively. The improved flame retardancy of the RPUF matrix was attributed to the increased expansion volume ratio of pEG‐P(MA) particles as exposed to fire. The dynamical mechanical analysis (DMA) showed that the incorporation of the core–shell particles could improve the storage modulus and tan δ of the RPUF composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011