Exfoliated and functionalized boron nitride nanosheets towards improved fire resistance and water tolerance of intumescent fire retardant coating

Abstract

In this work, the exfoliated and functionalized boron nitride (f‐BN) nanosheets were prepared via facile treatment and used in the intumescent fire retardant (IFR) coatings, which offer passive fire protection to the steel. To acquire the best fire resistance, the formula of the coating was optimized using response surface methodology (RSM) based on central composite design. According to the result, the optimal sample, with 36.2 wt% ammonium polyphosphate (APP), 27.4 wt% pentaerythritol (PER), 16.8 wt% melamine (MEL), and 7.9 wt% f‐BN, was prepared and its fire resistance was tested in our lab. At the end of fire resistance test, the backside temperature of optimal sample was only 185.2°C, which was very close to the RSM‐predicted result, indicating satisfactory fire resistance. During the test, the coating decomposed to form an intumescent char layer with high graphitization degree and compactness, thus suppressing the transfer of heat and protecting the underlying steel. In addition, the optimal coating possessed great water tolerance and thermal stability, and its water contact angle and char yield reached up to 66.7° and 40.5%, respectively. Hence, this IFR coating with satisfied fire retardancy and water tolerance has broad practical future in the fire safety of steel structure.

A phosphorus/silicon‐containing flame retardant based on eugenol for improving flame retardancy and smoke suppression of epoxy resin

“…It founds that the peak of P2p appears in the spectrum of the char residue of EP/ED7, and the characteristic peak of silicon element 48 In addition, the spectrum of Si2p can be deconvoluted into two peaks at 103.3 and 102.2 eV, corresponding to the Si O and Si C structures, respectively. 49 The above results further prove that both phosphorus and silicon elements are involved in the char formation during the degradation process. 50 gas phase.…”

“…For the spectrum of P2p, the fitted peaks at 133.7 and 132.6 eV correspond to the PO and POC structures, respectively, demonstrating the formation of polyphosphoric acid or pyrophosphoric acid structures in the cross‐linked carbon layer 48 . In addition, the spectrum of Si2p can be deconvoluted into two peaks at 103.3 and 102.2 eV, corresponding to the SiO and SiC structures, respectively 49 . The above results further prove that both phosphorus and silicon elements are involved in the char formation during the degradation process 50 …”

Influences of 4ZnO·B2O3·H2O whisker based intumescent flame retardant on the mechanical, flame retardant and smoke suppression properties of polypropylene composites

“…And then gas source is decomposed and massive non-flammable and non-toxic gases obtained, for the purpose of forming intumescent char residues. [22][23][24] These non-flammable gases and intumescent char residues are both beneficial for improving the flame retardancy of matrix. The most common IFR system is comprised by ammonium polyphosphate (APP) and pentaerythritol (PER), which acts as acid, gas sources, and charring source, respectively, with the optimal molar ratio of APP/PER about 3:1.…”

“…During a burning process, acid source reacted with charring source via esterification to obtain rudiments of expanded chars. And then gas source is decomposed and massive non‐flammable and non‐toxic gases obtained, for the purpose of forming intumescent char residues 22–24 . These non‐flammable gases and intumescent char residues are both beneficial for improving the flame retardancy of matrix.…”