An Organometallic Flame Retardant Containing P/N/S–Cu²⁺ for Epoxy Resins with Reduced Fire Hazard and Smoke Toxicity

Abstract

Epoxy resins (EPs) have superior physical and chemical features and are used in a wide range of applications in everyday life and engineering. However, its poor flame-retardant performance has hindered its wide application. Over the past decades of extensive research, metal ions have received increasing attention for their highly effective smoke suppression properties. In this work, we used an "aldol-ammonia condensation" reaction to structure the Schiff base structure, together with grafting using the reactive group on 9,10-dihydro-9-oxa-10-phospha-10-oxide (DOPO). Then, Cu 2+ was used to replace Na + to obtain DCSA-Cu flame retardant with smoke suppression properties. Attractively, DOPO and Cu 2+ can collaborate, thus effectively improving EP fire safety. At the same time, the addition of a double-bond initiator at low temperatures allows small molecules to form in situ macromolecular chains through the EP network, enhancing the tightness of the EP matrix. With the addition of 5 wt % flame retardant, the EP shows well-defined fire resistance, and the limiting oxygen index (LOI) reaches 36% with a significant reduction in the values of peak heat release (29.72%). In addition, the glass-transition temperature (T g ) of the samples with in situ formations of macromolecular chains was improved, and the physical properties of EP materials are also retained.

Reduction‐triggered Disassembly of Organic Cationic Nanorods Produces a Cysteine Protease Mimic (Miravet et al.)

“…It has to be noted that the k cat values are one order of magnitude higher than that of imidazole at the same pH (0.13 M À 1 s À 1 ) [36] and comparable to those reported for some amino acid and peptide derivatives at the same pH, with values ranging from 1.8 to 10.6 M À 1 s À 1 . [42][43][44][45] Therefore, the results indicate that the simple molecule ZC-Im, presenting vicinal thiol and imidazole units, could be regarded as a cysteine protease mimic. Only a few examples of such mimics have been reported in the literature, such as zwitterions produced from imidazole-thiol pairs, [46] peptides with different arrangements of the cysteine and histidine units, [47] and blends of cyclic dipeptides bearing histidine or cysteine.…”

“…Similarly, a 6‐fold increase was measured for DZC‐Im 2 @CPC . It has to be noted that the k cat values are one order of magnitude higher than that of imidazole at the same pH (0.13 M −1 s −1 ) [36] and comparable to those reported for some amino acid and peptide derivatives at the same pH, with values ranging from 1.8 to 10.6 M −1 s −1 [42–45] …”

A multi-element flame retardant containing boron and double-bond structure for enhancing mechanical properties and flame retardancy of epoxy resins

“…It significantly mitigates the adverse effects of the flame retardants added to the EP. Specifically, a flame retardant called DCSA-Cu, which contains the double-bond structure and organometallic metal was developed 26 . The results proved that the flame retardant containing double-bond structure can promote the formation of macromolecular chain structure within the material, and effectively reduce the adverse impact of flame retardants on the mechanical properties of EP while obtaining a good flame retardant effect.…”

Synthesis of multi‐element hybrid polyphosphonitrile microspheres and their flame retardant application in epoxy resins

“…The DOPO and Cu 2+ have a good synergistic effect, can effectively improve the flame retardant and smoke suppressing properties of EP. 10 Therefore, the development of metal-doped flame retardant is of great significance for improving the flame retardancy of polymers.…”

“…Li et al used 9,10‐dihydro‐9‐oxa‐10‐phospha‐10‐oxide (DOPO) grafted with Schiff base structure and substituted with metal ions to produce DCSA‐Cu flame retardant. The DOPO and Cu 2+ have a good synergistic effect, can effectively improve the flame retardant and smoke suppressing properties of EP 10 . Therefore, the development of metal‐doped flame retardant is of great significance for improving the flame retardancy of polymers.…”