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Synthesis of a hyperbranched polyamide oligomer containing DOPO for simultaneously enhancing the flame retardance and glass transition temperature of epoxy resin
Author(s) -
Luo Qinqin,
Sun Yulin,
Yu Biao,
Song Jiangli,
Tan Dexin,
Zhao Jianqing,
Yan Shijing
Publication year - 2021
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.5106
Subject(s) - epoxy , materials science , glass transition , fire retardant , oligomer , polyamide , fourier transform infrared spectroscopy , polymerization , cone calorimeter , composite material , polymer chemistry , chemical engineering , polymer , pyrolysis , char , engineering
Flame retardants endow epoxy resins (EP) with flame retardance, however, their introduction often lead to the decrease in the glass transition temperature ( T g ), which is an important property for EP. Therefore, it is significant to design and synthesize a high‐efficiency flame retardant that enhances flame retardance and T g of EP. To achieve this goal, a hyperbranched polyamide oligomer containing DOPO (HPD) was successfully synthesized by A 4 + B 2 polymerization and its structure was confirmed by FTIR, 1 H NMR, and 30 P NMR spectra and GPC. HPD was used as an additive flame retardant in epoxy resin, and its effect on the flame retardance and thermal properties of epoxy resin was studied. The epoxy resin with 7.5 wt% HPD reached UL‐94V‐0 rating and a higher LOI value of 29.6%, and its T g was 176.2°C, which is higher than the pure epoxy resin. Moreover, the results of cone calorimetry testing (CCT) and TG‐FTIR analysis suggested that the gas‐phase and condensed‐phase flame‐retarded roles of HPD delayed the time to ignition, and reduced the value of relevant combustion parameters, including the peak of heat release rate, average of heat release rate, total heat release, smoke production rate, and total smoke production. The analysis results of Py‐GC/MS test of HPD further confirmed that HPD was able to play the flame‐retarded role in the gaseous and condensed phases.