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Flame retardancy, thermal properties, and combustion behaviors of intumescent flame‐retardant polypropylene containing (poly) piperazine pyrophosphate and melamine polyphosphate
Author(s) -
Hu Zhi,
Zhong ZhiQiang,
Gong XiaoDi
Publication year - 2020
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.4996
Subject(s) - intumescent , ammonium polyphosphate , materials science , fire retardant , melamine , cone calorimeter , limiting oxygen index , thermogravimetric analysis , polypropylene , char , composite material , pentaerythritol , polyphosphate , piperazine , chemical engineering , polymer chemistry , phosphate , organic chemistry , pyrolysis , chemistry , engineering
A (poly) piperazine pyrophosphate (PIPP) was synthesized and its chemical structure was confirmed via Fourier transform infrared spectroscopy, 1 H nuclear magnetic resonance, and 31 P nuclear magnetic resonance. PIPP was used together with melamine polyphosphate (MPP) as an ammonium polyphosphate (APP)‐free intumescent flame retardant (IFR) to prepare several flame‐retardant polypropylene (FRPP) composites. The flame retardancy and burning behaviors of the composites were investigated via limiting oxygen index (LOI) determination, vertical burning tests (UL‐94), and cone calorimeter tests. The thermal properties were investigated by means of thermogravimetric analysis under nitrogen and air atmosphere. Use of PIPP and MPP together yielded an increase in the LOI value, a UL‐94 V‐0 rating, and a decrease in both the values of PHRR and THR in cone calorimetric analysis. Visual observations and scanning electronic microscopy confirmed the occurrence of char formation, which acted as a heat and fire barrier in the condense phase.