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Synergistic effect between silicone‐containing macromolecular charring agent and ammonium polyphosphate in flame retardant polypropylene
Author(s) -
Lai Xuejun,
Yin Changyu,
Li Hongqiang,
Zeng Xingrong
Publication year - 2015
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.41580
Subject(s) - ammonium polyphosphate , fire retardant , intumescent , charring , limiting oxygen index , thermogravimetric analysis , polypropylene , char , materials science , composite number , nuclear chemistry , thermogravimetry , composite material , chemical engineering , polymer chemistry , chemistry , pyrolysis , engineering
A novel silicone‐containing macromolecular charring agent (Si‐MCA) was synthesized via polycondensation, and it was combined with ammonium polyphosphate (APP) to flame retard polypropylene (PP). The results showed that Si‐MCA exhibited a good synergistic effect with APP in flame retardant PP. When the content of APP was 18.7 wt % and Si‐MCA was 6.3 wt %, the limiting oxygen index value of the PP/APP/Si‐MCA composite was 33.5%, and the vertical burning (UL 94) test classed a V‐0 rating. The peak heat release rate, total heat release, average mass loss rate, and total smoke production of the composite were also decreased significantly. Moreover, the PP/APP/Si‐MCA composite showed an outstanding water resistance. After soaking in 70°C water for 168 h, the PP/APP/Si‐MCA composite could still reach a UL 94 V‐0 rating at 20.0 wt % IFR loading, whereas the PP/APP/PER composite failed to pass the UL 94 test even at 25.0 wt % IFR loading. Thermogravimetric analysis, thermogravimetry‐Fourier transform infrared spectrometry, and scanning electron microscopy‐energy dispersive X‐ray spectrometry results revealed that a compact and thermostable intumescent char was formed by APP/Si‐MCA during burning, thus effectively improved the flame retardancy of PP. The possible synergistic mechanism between APP and Si‐MCA was also discussed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41580.