A novel oligomer containing DOPO and ferrocene groups: Synthesis, characterization, and its application in fire retardant epoxy resin

Abstract

A novel oligomer (PFDCHQ) based on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and ferrocene groups was synthesized successfully, aiming at improving the flame retardant efficiency of diglycidyl ether of bisphenol A epoxy resin (DGEBA). FTIR, 1 H NMR and 31 P NMR were used to confirm the chemical structure of PFDCHQ. The high char yields of 60.3 wt% and 20.1 wt% were obtained for PFDCHQ from TGA results in nitrogen and air atmosphere, respectively. The thermal degradation mechanism of PFDCHQ was investigated by TG-FTIR and Py-GC/MS. The limiting oxygen index (LOI) of EP-5 with 5 wt% loading of PFDCHQ increased to 32.0% and the UL-94 V-0 rating was achieved, showing a notable blowing-out effect. In contrast to EP-0, the peak of the heat release rate (pHRR) and total heat release (THR) of EP-5 decreased by 18.0% and 10.3%. The flame retardant mechanism of PFDCHQ in epoxy resin was studied by TG-FTIR, SEM and Raman. SEM and Raman results indicated the formation of coherent and dense char residue with high degree of graphitization due to the incorporation of PFDCHQ. In UL-94, the blowing-out effect dominantly accounted for the enhanced flame retardancy in combination with optimized char structure. Furthermore, the addition of PFDCHQ improved the Young's modulus compared to EP-0.

Flame retardant and toughening behaviors of bio‐based DOPO‐containing curing agent in epoxy thermoset

“…Due to excellent flame retardant effect of DOPO‐based derivatives, they had received outstanding attentions in flame retardant thermosets . Currently, some researchers designed DOPO derivatives with different structures to prepare flame retardant epoxy thermosets; those flame retardants showed excellent flame retardant efficiency …”

Synthesis of a furfural-based DOPO-containing co-curing agent for fire-safe epoxy resins

“…As can be seen, the gaseous products of EP-4.0 and EP-0 are identied by the absorptions at 1170 and 1251 cm À1 (ethers), 1598, 1503 and 1332 cm À1 (aromatic substances), 2343 and 2302 cm À1 (CO 2 ), 3037 and 2960 cm À1 (hydrocarbons), and 3658 cm À1 (phenols). 23,24 However, unlike EP-0, there is a new peak in the spectrum of EP-4.0, belonging to P-O-P (1057 cm À1 ), 25 which is generated from the decomposition of MBF-DOPO in EP-4.0 during combustion, indicating that the phosphorus-containing gaseous products play an important role in the gas-phase ame-retardant effect of MBF-DOPO. 1962 | RSC Adv., 2020, 10,[1956][1957][1958][1959][1960][1961][1962][1963][1964][1965] This journal is © The Royal Society of Chemistry 2020…”

Basalt Fiber-Based Flame Retardant Epoxy Composites: Preparation, Thermal Properties, and Flame Retardancy

“…Nevertheless, the intrinsic brittleness and high flammability still limit its application for several advanced areas. In order to tackle this issue, some approaches have been conducted to improve these drawbacks, such as incorporation of nanocarbon materials [ 1 ], layered double hydroxides (LDHs) [ 2 , 3 ], metal–organic frameworks (MOFs) [ 4 , 5 ], nanoclay [ 6 , 7 ], and phosphorus-containing flame retardants [ 8 , 9 ]. Concerning the environmental friendliness and high-efficiency, intumescent fire retardants (IFRs) have been long-term developed and attracted numerous attentions to polymers [ 10 , 11 , 12 ].…”