Conceptually Novel Few-Layer Black Phosphorus/Supramolecular Coalition: Noncovalent Functionalization Toward Fire Safety Enhancement

Abstract

Black phosphorus (BP) has been widely concerned in the field of composite materials because of its special geometrical and physicochemical properties. As a red phosphorus allotrope, BP has the dual function of physical barrier and catalytic carbonization and has the potential to be a highly effective flame retardant. In this article, the aminated BP/melamine cyanurate (BP–NH–MCA) coalition with a sandwich structure was prepared by an in situ self-assembly of MCA supramolecules on the surface of aminated BP. TEM, SEM, and the surface distribution scan results showed that the hybrid nanosheets were successfully fabricated and uniformly distributed in the matrix. The analysis of the data of cone calorimetry showed that with the loading of BP–NH–MCA increasing from 0.5 to 2.0 wt %, the peak value of heat release rate of composites decreases by 21.9–47.2%, and the total heat release value decreases by 26.7–42.3%. In addition, the EP/BP–NH–MCA2.0 nanocomposite has the lowest emission intensity of typical volatile products, including toxic CO during combustion, compared to EP/BP2.0 and pure EP samples, significantly improving the fire safety of composites. This work provides a reference for the application of BP in flame-retardant fields and reveals the flame-retardant mechanism of its hybrid materials.

Optimization of Flexible Nacre-Like Cellulose Nanofiber Films by a Covalent Overlapping Method: Excellent Thermal Conductivity and Superior Flame Resistance

“…The peaks at 129.4 and 130.3 eV correspond to the P 2p 1/2 and P 2p 3/2 signals in the P–P bond, respectively, and the P ox peak at 134.2 eV is attributed to the oxide produced by the slight oxidation of the BP surface. Most notably, compared with BP-bulk, the P–N bond at 133.4 eV in the P 2p spectra (Figure S3b) and the N–P bond at 401.4 eV in the N 1s spectra (Figure S3c) of BP-NH 2 were also found, proving the success of functionalization . Additionally, the infrared absorption peaks at 3200 and 1015 cm –1 in the FTIR spectra of BP-NH 2 (Figure g) are attributed to N–H and P–N, respectively .…”

“…Most notably, compared with BP-bulk, the P−N bond at 133.4 eV in the P 2p spectra (Figure S3b) and the N−P bond at 401.4 eV in the N 1s spectra (Figure S3c) of BP-NH 2 were also found, proving the success of functionalization. 37 Additionally, the infrared absorption peaks at 3200 and 1015 cm −1 in the FTIR spectra of BP-NH 2 (Figure 2g) are attributed to N−H and P− N, respectively. 38 As a simultaneous process, the structural changes caused by exfoliation were studied by XRD.…”

Multifunctional Lightweight Guanidine Phosphate/Poly(Vinyl Alcohol) Melamine-Based Hybrid Foam for Superior Thermal Insulation and Flame Retardancy

“…Unlike the MF-0 foam, the C 1s spectrum of the MF-1.5 foam appears with an extra peak at 287.4 eV ascribed to the CC groups, confirming the presence of an aromatic structure in the char residue (Figure c). It is the aromatic structure in the char layer that endows the MF-1.5 foam with excellent thermal stability and flame retardancy. , Figure d depicts the P 2p spectrum of the MF-1.5 foam, and the appearance of P–O and PO groups illustrates the GP pyrolyzed into phosphoric acid, metaphosphoric acid, or other phosphorous compounds to participate in the char layer formation . Based on the above results, the pyrolysis process and decomposition products of the MF-1.5 foam have changed with the addition of GP, resulting in the formation of a dense char layer and the enhancement of flame retardancy.…”

“…The spectra are distinguished into two broad peaks around 1370 and 1590 cm –1 , which correspond to the D-band and G-band, respectively. In general, the integrated intensity ratio of D-band and G-band ( I D / I G ) is adopted to estimate the graphitization degree of the char residue, with the lower I D / I G value indicating a higher graphitization degree . The MF-1.5 foam possesses a lower I D / I G value of 2.73, demonstrating the splendid charring ability of GP.…”

Design of New Functional Flame‐Retardant System for High‐Performance Epoxy Thermosets Enabled by Bifunctional Few‐Layer Black Phosphorus and Synergistic Strategy

“…Figure 3a illustrates the XRD plots of BP and BP-NH 2 and the correspondences between the diffraction peaks at different 2𝜃 and the crystal planes in the orthorhombic phase of BP-NH 2 are revealed in Table S1 (Supporting Information). [43] Compared with the strong and sharp diffraction peaks of BP, the weaker peak intensity of BP-NH 2 implies that it is exfoliated into nanosheets during the ball milling process. [44] In addition, the diffraction peaks of BP-NH 2 shift to larger angles because the introduction of atom N with smaller radius than the main atom P leads to smaller lattice parameters and interplanar crystal spacing.…”