Synergistic Flame-Retardant and Smoke Suppressions Effects of Polyethylene Glycol Borate in Transparent Intumescent Fire-Retardant Coatings

A series of flexible phosphate flame retardants (PPB) with different polyethylene glycol borate (PEG-BA) contents were synthesized by the esterification of phosphate ester acid (PEA) and PEG-BA, and their structures were well characterized by FT-IR and 1H-NMR. Then, the PPBs were applied into amino resins to prepare a series of transparent fire-retardant coatings. The effects of PEG-BA on the flame retardancy and smoke suppression properties of the transparent intumescent fire-retardant coatings were investigated by fire performance test, cone calorimeter and smoke density meter. The synergistic mechanism of PEG-BA in the coatings was also analyzed by thermogravimetric analyzer (TGA), SEM and FT-IR. The results show that the introduction of PEG-BA into transparent fire-retardant coatings can effectively improve the thermal stability, flame retardancy and smoke suppression properties of the coatings. When the mass ratio of PEA to PEG is 4:1, the coating has the lowest heat release rate, total heat release and smoke density, and the back stable temperature of samples is 146℃. The char residue analysis shows that the addition of PEG-BA can promote the formation of more crosslinked structures such as P-O-C, P-O-B and B-O-C, thus forming a more compact and thermally stable char layer. © 2019, Editorial Board of Polymer Materials Science & Engineering. All right reserved.