The design of highly fire-safe and smoke-suppressive single-component epoxy (EP) resins combining modest curing temperature and fast curing rate has been desirable yet very challenging in both academia and industry. Herein, we report a facile design of a phosphorus/imidazole-containing single-component EP system via incorporating 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and a flame-retardant curing agent cyclotriphosphazene-modified benzimidazole (BICP) into EP. Our results show that EP/DOPO/BICP exhibits a rapid modest-temperature curing feature because DOPO serves as a switch that triggers BICP to release benzimidazole (BIM) via substitution reaction in the initial curing stage. Moreover, as-prepared EP/DOPO/BICP shows outstanding fire retardancy, reflected by the high limited oxygen index (LOI) of 38.3% and UL-94 V-0 rating. Compared to the control EP system, the peak of heat release rate (PHRR) and total smoke production (TSP) of EP/DOPO/BICP remarkably decrease by ~74.5% and ~50.6%, respectively, which is superior to previously-reported flame-retardant P-containing epoxy counterparts. The significant enhancements in flame retardancy and smoke suppression are mainly due to the formation of a highly intumescent char layer and the reduced burning degree of pyrolysis fragments. This work offers a facile and scalable strategy for creating fast-curing, modest-temperature curable, highly fire-resistant and smoke-suppressive one-component epoxy systems applicable to large-scale industrial production.

A highly fire-safe and smoke-suppressive single-component epoxy resin with switchable curing temperature and rapid curing rate

Highly efficient, transparent, and environment-friendly flame-retardant coating for cotton fabric

An overview of alginates as flame-retardant materials: Pyrolysis behaviors, flame retardancy, and applications.

In order to develop high-performance epoxy resins (EP), a novel phosphorus/nitrogen-containing phenylsiloxane macromolecule (DP-PPD) has been synthesized as a multi-functional additive. The DP-PPD macromolecules can simultaneously enhance the mechanical strength, flame retardancy, and smoke suppression performance for EP at low loading. Compared with unmodified EP, only by introducing 2 wt% DP-PPD, the impact strength, flexural strength and flexural modulus are greatly increased by 100%, 12.9% and 38.7%, respectively, due to flexible phenylsiloxane units and covalent interaction with EP matrix. Meanwhile, the resultant EP containing barely 3 wt% DP-PPD reaches V-0 rating in UL-94 test and shows a high limiting oxygen index of 30.1%. The cone calorimeter test results reveal that the peak of heat release rate, total heat release, and total smoke release of 9%DP-PPD/EP are decreased by 31.4%, 35.4%, and 20.0%, respectively, compared to those of unmodified EP. The mechanism analysis confirms that abundant aromatic rings, siloxane, and DOPO units in DP-PPD can synergistically promote the formation of P–Si-containing hybrid char layer for EP resins during combustion, thus leading to satisfied flame retardancy and smoke suppression. Meanwhile, the reduction of volatilized organic products and the emergence of phosphorous fragments indicates the flame inhibition effect of DP-PPD. Moreover, DP-PPD has little negative effect on the heat resistance of EP. This efficient single-component multi-functional additive provides a new strategy for the construction of high-performance macromolecular materials.

High strength, low flammability, and smoke suppression for epoxy thermoset enabled by a low-loading phosphorus-nitrogen-silicon compound

In order to improve the flame retardancy and smoke suppression of epoxy resin (EP) simultaneously, we synthesized a melamine phenylhypophosphonate named as MABP via a simple one-step method and used it to modify EP materials As expected, the addition of MABP not only largely improved the flame retardancy but also restrained the smoke release of EP For details, when the content of MABP was 10 wt%, the EP composite possessed a limiting oxygen index value of 33% and achieved to a UL-94 V-0 rating as well as its PHRR, THR and TSP values decreased by 551%, 271% and 60% compared with that of neat EP, respectively In addition, the flame-retardant mechanism was investigated by multiple instruments, and the corresponding results exhibited that the MABP could improve the compactness of char layer in condense phase and exerted fire-inhibition effect in gaseous phase

A facile one-step synthesis of highly efficient melamine salt reactive flame retardant for epoxy resin

An efficient organic/inorganic phosphorus–nitrogen–silicon flame retardant towards low-flammability epoxy resin

Novel organophosphorus compound with amine groups towards self-extinguishing epoxy resins at low loading

Novel multi-element DOPO derivative toward low-flammability epoxy resin

A novel organic–inorganic hybrid particle (JF633-SBA-15A) was successfully prepared by solution blending method using hybrid hyperbranched polyether polyol (JF633) and surface-modified mesoporous (SBA-15). Further, JF633-SBA-15A/EP composites were fabricated by melt-blending method. The structure and morphology of JF633-SBA-15A were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry analysis, nitrogen adsorption–desorption, and scanning electron microscopy. The mechanical and dynamic mechanical properties of JF633-SBA-15A/EP were also studied. The results demonstrated that the prepared JF633-SBA-15A hybrid particles had excellent thermal stability and unique mesoporous structural characteristics. Compared with pure EP, the maximum degradation temperature of the composites decreased and the thermal stability increased at high temperature. Notably, the JF633-SBA-15A/EP composite had better comprehensive performance. The impact strength and temperature of the glass transition (Tg) of JF633-SBA-15A/EP composites with 1.0 wt% JF633-SBA-15A increased by 32% and 23 °C, respectively. SEM images of the cross-section of the composite which reinforced with hybrid particles exhibited a rough surface and multiple dimples, indicating a ductile fracture.

Synthesis of a Novel Mesoporous Inorganic–Organic Hybrid and Its Application in Epoxy Resins

The invention discloses a preparation method of a hollow mesoporous silica microsphere-reinforced epoxy resin composite material. The preparation method comprises preparing hollow mesoporous silica microspheres, carrying out coupling treatment through a silane coupling agent, adding the coupled microspheres into an epoxy resin oligomer, carrying out vacuum mixing, ultrasonic treatment and vacuum-pumping treatment to obtain a hollow mesoporous silica microsphere/epoxy resin mixture, adding a curing agent and a promoter into the mixture, carrying out curing at 80-100 DEG C for 3-6h, and carryingout curing at 140-180 DEG C for 4-8h to obtain the hollow mesoporous silica microsphere-reinforced epoxy resin composite material. The preparation method has simple processes, realizes a low cost andeasily satisfies the requirements of industrial production. The hollow mesoporous silica microsphere-reinforced epoxy resin composite material has good comprehensive performances. Compared with the pure epoxy resin cured product, the composite material has higher glass-transition temperature, higher storage modulus, better tensile strength and better bending strength.

Luo Haiqiang

Papers

An efficient organic/inorganic phosphorus–nitrogen–silicon flame retardant towards low-flammability epoxy resin

Novel organophosphorus compound with amine groups towards self-extinguishing epoxy resins at low loading

Novel multi-element DOPO derivative toward low-flammability epoxy resin

Synthesis of a Novel Mesoporous Inorganic–Organic Hybrid and Its Application in Epoxy Resins

Preparation method of hollow mesoporous silica microsphere-reinforced epoxy resin composite material