The high-temperature self-crosslinking contribution of azobenzene groups to the flame retardance and anti-dripping of copolyesters

Flame‐retardant poly (ethylene terephthalate) enabled by a novel melamine polyphosphate nanowire

“…The flame retardancy of PET, PET/FR, and PET/FR C nanocomposites was evaluated by LOI and vertical combustion test (UL‐94); relevant data were summarized in Table . Polymeric materials displaying LOI values over 26% would exhibit self‐extinguishing behavior and were considered to possess high flame retardance . The pure PET only had an LOI value of 20.5%, which was highly flammable in air atmosphere.…”

“…To get more understanding of the flame retardation mechanism of PET/FR nanocomposites in condensed phase, Raman spectroscopy was employed to further investigate the carbonaceous structure of char residue . In the Raman spectrum of PET (Figure c), there were two characteristic overlapping peaks at 1350 cm −1 (D band) and 1580 cm −1 (G band), which corresponded to amorphous and organized graphitic char structure.…”

“…To get more understanding of the flame retardation mechanism of PET/FR nanocomposites in condensed phase, Raman spectroscopy was employed to further investigate the carbonaceous structure of char residue. 24 In the Raman spectrum of PET (Figure 9c), there were two characteristic overlapping peaks at 1350 cm −1 (D band) and 1580 cm −1 (G band), which corresponded to amorphous and organized gra- acted a barrier to mass and heat transfer between the gas phase and the condensed phase, which slowed down the escape of organic volatiles during the combustion of PET. 35,36 Just because of the excellent catalytic carbonization effect caused by MPP nanowires, the fire hazard of PET material was reduced greatly and obviously.…”

PET-based copolyesters with bisphenol A or bisphenol F structural units: Their distinct differences in pyrolysis behaviours and flame-retardant performances

“…However, most phosphorus-containing copolyesters will drip seriously in the fire, leading to secondary damage and scald for human body [7,8]. Recently, our research group copolymerized thermo-cross-linkable monomers or ionic monomer into PET, which can promote the carbonization reactions of copolyester during combustion [9][10][11]. Via chemical cross-linking or ionic aggregation, the char residue was enhanced, and the release of volatile products was decreased, as well as the melt dripping was inhibited.…”

Dual Fire Retardant Action: The Combined Gas and Condensed Phase Effects of Azo-Modified NiZnAl Layered Double Hydroxide on Intumescent Polypropylene

“…Wilen and colleagues have synthesized a series of azo-based FRs such as azo (R-N=N-R) and/or triazenes (R-N=N-N-R), which achieved excellent fire retardancy in a PP system 33,34 and a PE system 35 . Additionally, incorporation of azobenzene groups in copolyester can significantly increase the amount of residue and thermo-oxidative stability due to its high-temperature self-crosslinking characteristics 36 . Moreover, the azo compounds possess a good UV absorption ability 37 .…”