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Fire retardant properties of intumescent polypropylene composites filled with calcium carbonate
Author(s) -
Isitman Nihat Ali,
Dogan Mehmet,
Bayramli Erdal,
Kaynak Cevdet
Publication year - 2011
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.21901
Subject(s) - intumescent , pentaerythritol , ammonium polyphosphate , fire retardant , materials science , composite material , limiting oxygen index , polypropylene , calcium carbonate , calorimetry , portlandite , combustion , char , chemistry , organic chemistry , physics , portland cement , cement , thermodynamics
This study was aimed to investigate the influence of calcium carbonate (CaCO 3 ), a widely used filler, on the fire retardancy of intumescent polypropylene composites. Two intumescent systems based on (1) mixture of ammonium polyphosphate (APP) and pentaerythritol and (2) surface‐modified APP (m‐APP) were examined. In terms of steady heat release rate, total heat evolved, and fire growth index determined by mass loss calorimetry, m‐APP performed markedly superior to APP‐pentaerythritol. The presence of CaCO 3 in both intumescent formulations caused significant losses in fire retardant performance assessed by mass loss calorimetry, limiting oxygen index and UL‐94 tests. Peak rates of heat release and mass loss during combustion, and total heat evolved on combustion were increased, whereas time to ignition was decreased. Characterization of fire residues ascribed the mechanism of deterioration in fire retardancy to the formation of porous and nonexpanded crystalline calcium phosphate/CaCO 3 residues during combustion rather than the amorphous protective intumescent chars formed in the absence of CaCO 3 . POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers