Application Of Epoxy Research Articles

Diphenylphosphine oxide derivative with a symmetrical structure as an efficient flame retardant for application in epoxy resin

AbstractA fresh phosphorus‐containing fireproofing agent (oxybis(4,1‐phenylene))bis((2,5‐dihydroxyphenyl)(phenyl)phosphine oxide) (ODDPO‐HQ) was synthesized by a simple two‐step reaction. The effect of ODDPO‐HQ on the glass transition temperature (Tg), crosslinking density, thermal stability, fire resistance, dielectric performances, hydrophobicity, and water absorption of epoxy resin (EP) was studied. EP/ODDPO‐HQ containing 1.2 wt% phosphorus not only achieved the vertical burning V‐0 grade with a limited oxygen index of 28.9% but also maintained good thermal stability. Compared to unmodified EP, its Tg value has only decreased by 7.2°C. Detailed studies revealed that the excellent flame resistance of ODDPO‐HQ for epoxies was ascribed to the flame suppression both in the gaseous phase and condensed phase, especially the obvious barrier effect. Although the water uptake of the modified epoxies slightly rose with the content of ODDPO‐HQ caused by the reduction of the crosslinking density within the matrix, it did not adversely affect the properties of the polymer. The modified epoxies showed reduced dielectric constant and dielectric loss values, and the contact angle of EP/ODDPO‐HQ samples increased as the flame retardant content rose, which might be due to the symmetrical structure of ODDPO‐HQ reducing the polarity. Our study presents an easy approach for producing high‐performance epoxies.

Phenyl, propyl polysiloxane modified epoxy resin II: The co-continuous phase, concurrently strengthening and toughening mechanism

The applications of epoxy resins are restricted in certain areas due to their brittleness, while improving the epoxy toughness always compromises their strength. We reported a phenyl, propyl polysiloxane modified epoxy resins with excellent tensile strength and toughness before. In this study, the mechanism of strengthening and toughening are studied and elaborated. Compared to cured EP resin (EP), cured P/E resin (P/E20) significantly improved the tensile strength, elongation at break, impact strength, and critical strain energy release rate (GIc) by 45 %, 248 %, 18 %, and 512 %, respectively. Fracture analysis of the P/E20 revealed the appearance of parabolic markings, typical and convincing evidence of ductile fracture, indicating good toughness of the resin. AFM height and Young's modulus plots reveal the complex details of the dimples and the co-continuous phases, which provide the strong evidence to explain the reinforcement and toughening mechanism.

Boron nitride nanosheets synergized with two‐dimensional micron silver sheets to enhance thermal conductivity and insulation of epoxy resin composites

AbstractWith the rapid progress of the advanced electronic device industry, precision electronic instruments are gradually developing towards miniaturization. In this case, epoxy resin gradually attracts people's attention, but its intrinsic thermal conductivity is not high, and the resulting heat dissipation problem limits the further application of epoxy resin in the field of electronic packaging. Therefore, how to enhance the thermal conductivity of epoxy resins has become an urgent problem in the field of electronic packaging. In this work, BNNS was successfully prepared by stripping h‐BN into a flaky two‐dimensional material, which was added to the epoxy resin as a filler to make the composite material. And on the basis of the above, two‐dimensional micron silver flakes (AgMS) with different mass fractions were added to the composites, and the AgMS/BNNS/EP composites were successfully prepared. When BNNS was 25 wt% and AgMS was 1 wt%, its out‐of‐plane thermal conductivity was enhanced from 0.17 W m−1 K−1 of pure epoxy resin to 0.43 W m−1 K−1. When BNNS was 20 wt% and AgMS was 1 wt%, the breakdown strength was enhanced from 105 kV/mm for pure epoxy to 130 kV/mm. This work provides a new strategy for synthesizing high‐thermal‐conductivity epoxy matrix composites.

Preparation of halogen-free flame retardant curing agent and its application in epoxy resin

9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-N-Aminoethylpiperazine (DOPO-AEP), a phosphorus and nitrogen intumescent flame retardant curing agent was prepared by using acetonitrile as solvent using 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and N-aminoethylpiperazine (AEP) as raw materials. The structure of the flame retardant curing agent DOPO-AEP was analyzed Fourier Transform Infrared Spectrometer (FTIR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESI-MS), and the synthesis method of the target product was determined. In addition, the content of char residue was determined by thermogravimetric analyzer, and its thermal properties were comprehensively explored, and based on the obtained results, the curable epoxy resin was selected to prepare DOPO-AEP/EP flame retardant composites. According to the amount of DOPO-AEP added product, different proportions of DOPO-AEP/EP flame retardant composites were prepared, and the actual impact of flame retardant properties and mechanical properties of epoxy resin in different proportions was explored. When the content of DOPO-AEP is 35%, the limiting oxygen index of DOPO-AEP/EP reaches 29.9, which has a significant increase compared with the limiting oxygen index of pure epoxy resin of 19.8, but compared with the content of DOPO-AEP of 30%, the limiting oxygen index of DOPO-AEP/EP is 28.7, and there is no significant increase change. Comprehensive analysis shows that when the component content of DOPO-AEP is 30%, the flame retardant system has a tensile strength of 29.0 MPa, an impact strength of 4.5Kj/m2 and a flexural strength of 73.9 MPa, and its limiting oxygen index is as high as 28.7, and the comprehensive performance of the system is the best. By testing the surface morphology of the flame retardant composites after combustion by SEM, it was found that a dense char layer was formed on the surface of the epoxy resin cured char residue and foamed obviously, indicating that the flame retardant curing performance of DOPO-AEP was good.

Synthesis of magnesium hydroxide flame retardant based on microcrystalline magnesite and its application in epoxy resin

Abstract A nanoscale hexagonal flake magnesium hydroxide (MH) flame retardant was prepared by a hydrothermal method using Tibetan microcrystalline magnesite as the raw material. The synthesized samples were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FSEM), thermogravimetric analysis-differential scanning calorimetry (TG-DSC), and laser particle size analysis. When subjected to hydrothermal treatment at 180 °C for a duration of 8 h in a solution containing 6 mol l−1 NaOH, and with the incorporation of 4 wt% of the surfactant polyethylene glycol 2000 (PEG2000), hexagonal flake MH, possessing an average particle size of 378.3 nm, was successfully synthesized. The study conducted an examination of the thermal, mechanical, and flame-retardant properties of both EP and EP/MH composites. The results revealed that the incorporation of 9 wt% MH led to a notable reduction in the peak heat release rate, total smoke production, and mass loss rate of the EP/MH composites by 36%, 14.5%, and 33.3% respectively, as compared to the pure EP. Remarkably, the tensile and flexural strength of the composite exhibited minimal impact.

Preparation of P/N/Si‐containing covalent organic framework‐based flame retardants and their application in epoxy resins

AbstractBalancing the enhancement of flame retardancy of epoxy resin while maintaining its mechanical capacities intact poses a significant challenge in the realm of flame‐retardant epoxy resins. To reach the above objectives, a COF‐based synergistic flame retardant with phosphorus, nitrogen, and silicon (PA‐COF@MT) was synthesized using phytic acid (PA), montmorillonite (MT), and covalent organic framework (COF). When PA‐COF@MT was added at 4 wt%, EP/PA‐COF@MT exhibited a reduction of 42.1% in peak heat release rate (PHRR), 45.84% in total heat release (THR), and 59.8% in total smoke production (TSP) compared with the pure EP. LOI increased by 30.5% and UL‐94 tested to V‐0 grade. flame‐retardant index (FRI) value of 3.03, achieving a “good” rating. Fire growth indices and mean effective combustion heat were increased while mechanical properties also improved. These findings suggest that the flame retarding mechanism of PA‐COF@MT is mainly through vapor phase and condensed phase actions. The combined effects of phosphorus, nitrogen, and silicon make the surface of carbon residue solid and dense, resulting in excellent heat insulation and smoke suppression effects. In simple terms, this study provides new insights into COF‐based flame retardants. Combining low‐cost and simple preparation methods, PA‐COF@MT has broad application prospects in flame‐retardant epoxy resin systems.

Effect of Condensed Water at an Alumina/Epoxy Resin Interface on Curing Reaction.

The adhesion of epoxy adhesives to aluminum materials is an important issue in assembling parts for lightweight mobility. Aluminum surfaces typically possess an oxide layer, which readily adsorbs water. In this study, the aggregation states of water and its effect on the curing reaction were examined by placing a water layer between an amorphous alumina surface and a mixture of epoxy and amine components. This study used molecular dynamics simulations and density functional theory calculations. Before the reaction, water molecules strongly adsorbed onto the alumina surface, aggregating excess water. Some water diffused into the epoxy/amine mixture, accelerating the diffusion of unreacted substances. This led to faster reaction kinetics, particularly in proximity to the alumina surface. The adsorption of water molecules onto the alumina surface and the aggregation of excess water were similarly observed even after the curing process. Subsequently, the interaction between the alumina surface and various functional groups of the epoxy/amine mixture was evaluated before and after the reaction. Epoxy monomers had little interaction with the alumina surface before the reaction, whereas hydroxy groups formed by the ring-opening reaction of epoxy groups exhibited notable interaction. Conversely, sulfonyl and amino groups in amine compounds formed hydrogen bonds with OH groups on the alumina surface before the reaction. However, after the reaction, amino groups weakened their interaction with the alumina OH groups as they transformed from primary to tertiary during the curing reaction. Both epoxy and amine monomers/fragments similarly interacted with water molecules, both before and after the reaction. The insights gained from this study are expected to contribute to a better understanding of the impact of moisture absorption on the application of epoxy resins.

Synthesis of aminopyrazine‐based fire resistant additive and its application in epoxy resin

AbstractA new fire retardency APD was synthesized successfully by the condensation between 2‐aminopyrazine and DOPO, and target product APD was characterized by NMR. Absorption peak at 12.6 ppm in 31P NMR verified complete consumption of the reactant DOPO and further confirmed the structure of APD. The safety of epoxy resin (EP) in fire disaster was dramatically improved by introduction of APD. Epoxy resin modified with 8% APD succeeded in vertical burning (UL‐94) test with V‐0 rating and limited oxygen index (LOI) of EP/8% APD was also improved to 33.9%. Cone calorimeter (CC) test further exhibited fire resistant effect of APD on EP in detail. 11.0 g APD reduced total heat release of 100 g EP to 35.1% and reduced total smoke product of 100 g EP to 19.9%. Char residue from CC test of EP/8% APD was analyzed by Raman, XPS, SEM, and FTIR tests. The results of these tests indicated that compact morphology of char residue from EP/8% APD possessed a positive effect in blocking fire spread.Highlights APD was synthesized and fire resistant EP was made. EP/APD acquired outstanding fire resistance and moderate mechanical properties. APD played fire resistant role in gas phase and condensed phase.

Mechanical characterization of PEEK-CF/PEEK sandwich structures prepared via a combination of fused filament fabrication and epoxy post-bonding

Poly-ether-ether-ketone (PEEK) and carbon-fiber-reinforced PEEK (PEEK-CF) are examples of engineering thermoplastics with exceptional mechanical properties. In the context of Fused Filament Fabrication (FFF), the interlayer bonding between PEEK and PEEK-CF has a significant impact on the mechanical properties of printed components. Epoxy resin is used to enhance the interfacial bonding between PEEK and PEEK-CF due to its remarkable adhesive properties, while preserving the dimensional and weight attributes of the bonded sandwich structure. The application of epoxy resin as a post-processing technique enables the creation of intricate geometric designs within the bonded sandwich structures. This study presents a straightforward technique for producing sandwich structures using PEEK and PEEK-CF, followed by improving their mechanical properties through isothermal annealing. We conduct systematic single-factor experiments to explore the mechanical advantages of FFF-printed PEEK and PEEK-CF via three-point bending tests on individually printed monolithic specimens. Furthermore, mono-material specimens are bonded using epoxy resin to form dual-material bending specimens. Our findings reveal an optimal sequence: after isothermal annealing, mono-material specimens bonded with epoxy resin exhibit superior flexural strength and modulus. In addition, an in-depth examination of the meso-structure and fracture morphology of FFF-printed sandwich structures after bonding and heat treatment reveals insights into toughening and reinforcement mechanisms. This analysis is complemented by corresponding finite element simulations to validate the results. Notably, our research highlights the successful optimization of interlayer structures, facilitating the creation of sandwich structures with superior mechanical performance.

Synthesis of a Novel P/N-Triazine-Containing Ring Flame Retardant and Its Application in Epoxy Resin.

To meet the environmental protection and flame retardancy requirements for epoxy resins (EPs) in certain fields, in this study, a novel triazine-ring-containing DOPO-derived compound (VDPD), derived from vanillin, 2,4-Diamino-6-phenyl-1,3,5-triazine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), was synthesized using a one-pot method. Flame-retardant epoxy resin (FREP) was prepared by adding various ratios of VDPD to EP and curing with 4,4-diaminodiphenylmethane (DDM). The curing behavior, thermal stability, mechanical properties, and flame-retardant properties of the FREP were examined in various tests. According to the results, when the amount of VDPD added to the EP increased, the glass transition temperature of the FREP decreased linearly, and the flame-retardant properties gradually improved. With a 0.4 wt.% P content, the vertical burning rating of EP/DDM/VDPD-0.4 (according to the theoretical content of VDPD) reached the V-0 level, and the LOI value reached 33.1%. In addition, the results of a CCT showed that the peak heat release rate (PHRR) of EP/DDM/VDPD-0.4 decreased by 32% in comparison with that of the EP. Furthermore, compared with those of the EP, the tensile strength of EP/DDM/VDPD-0.4 decreased from 80.2 MPa to 74.3 MPa, only decreasing by 6 MPa, and the tensile modulus increased. Overall, VDPD can maintain the mechanical properties of EP and effectively improve its flame-retardant properties.

A metal-based microencapsulated phase change material (MEPCM) with high thermal conductivity, electrical insulation and flame retardancy and its application in epoxy resin

Using the “double-layer coating, sacrificial inner layer” method, MEPCM with a thermal expansion void was prepared by encapsulating Sn particles into a magnesium hydroxide shell. The results showed that MEPCM exhibited better thermal reliability than those without a thermal expansion void. More importantly, the Sn was selected as the core material that MEPCM was enabled to have large volume latent heat (425.2 J/cm3) and high thermal conductivity (10.06 W/m·K), and magnesium hydroxide was chosen as the shell material that MEPCM was given great heat absorption ability (260 J/g), excellent electrical insulation performance and flame retardancy. By adding 20 vol% MEPCM to EP, the thermal conductivity of the composite improved 164.9 %. The volume resistivity of EP/MEPCM composites was 2.1 × 1012 Ω·cm. The pHRR and THR of EP/MEPCM composites were only 471.64 kW/m2 and 12.95 m2, respectively. The existence of MEPCM enhanced the thermal conductivity, electrical insulation performance and flame retardancy of EP.

A simple synthesis of a guaiacol based reactive flame retardant and its application in epoxy resins

Under the premise of ensuring the flame retardancy and heat resistance of flame-retardant epoxy resin (FREP), the development of bio-based reactive flame retardants has a broad application prospect.

Synthesis of a novel bis(diphenylphosphinyl)-containing pyromellitimide and its application in epoxy resins

Epoxy resin (EP) is one of the most widely used thermosetting resins. Developing EP with high-comprehensive properties still holds great significance. Thus, a novel bis(diphenylphosphinyl)-containing pyromellitimide (abbreviated as DTPMI) was synthesized as a multi-functional additive for EP. Compared with pure EP, 6 wt.% of DTPMI could increase the limited oxygen index (LOI) value of the EP/6DTPMI from 23.0 % to 28.5 %, with a 30.5 % reduction in the peak heat release rate. The satisfactory flame retardancy for the EP/6DTPMI was attributed to the formation of a thermal oxidation-resistant char layer during the combustion, effectively reducing the material’s burning intensity and fire hazard. Surprisingly, the dielectric constant and loss of the EP/6DTPMI could be significantly reduced to 2.69 and 0.0527 at 10 MHz, respectively. Also, its contact angle to water was raised from 63.1° (pure EP) to 92.4°, decreasing the surface moisture absorption of the EP/DTPMI thermosets. Besides, the incorporation of DTPMI hardly deteriorated the thermal and mechanical properties of the EP/DTPMI thermosets. This work provided a feasible approach for fabricating the EP thermosets with high-comprehensive performance, especially for flame retardancy and dielectric performance, and proposed potential application prospects of the EP/DTPMI thermosets.

Preparation of a novel flame retardant based on phosphorus/nitrogen modified lignin with metal–organic framework and its application in epoxy resin

Preparation of a novel flame retardant based on phosphorus/nitrogen modified lignin with metal–organic framework and its application in epoxy resin

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

AbstractIn this paper, Salen‐Ni basis polyphosphazene microsphere (Salen‐PZN‐Ni), boric acid (BA), and 3‐aminopropyltriethoxysilane (KH‐550) were used as raw materials to prepare a new flame retardant Salen‐PZN‐Ni@BA@KH‐550 by surface modification. The thermal and flame retardant properties of epoxy resin (EP) composites were studied. The introduction of Salen‐PZN‐Ni@BA@KH‐550 refined the thermal stability of EP composites, as well as the amount of carbon residue at 800°C. At 5 wt% of Salen‐PZN‐Ni@BA@KH‐550, the limiting oxygen index (LOI) of EP composites is increased from 25.4% to 30.5% and UL‐94 has been achieved with a V‐1 rating. Meanwhile, the mechanical properties of Salen‐PZN‐Ni@BA@KH‐550/EP composites were also improved. In addition, the good char formation ability of Salen‐PZN‐Ni@BA@KH‐550 caused the reduction of peak heat release rate, total heat release rate, maximum average heat release rate and total smoke generation of the EP composites. All these results indicate that Salen‐PZN‐Ni@BA@KH‐550/EP composites have a wider range of applications.

Synthesis of solid reactive organophosphorus‐nitrogen flame retardant and its application in epoxy resin

AbstractA solid reactive organophosphorus‐nitrogen flame retardant 4N‐BDP was devised and synthesized in order to address the flaws of the widely used organophosphorus flame retardants BDP as well as the issue of flame retardant modification of epoxy resin (EP). A series of flame‐retardant EP composites were prepared by adding 4N‐BDP and BDP to EP in a specific proportion. The flame‐retardant properties of the two were compared, and the flame‐retardant mechanism of 4N‐BDP was deeply analyzed. The results of the UL‐94 test revealed that sample 4N‐BDP‐6 obtained the greatest V‐0 level, while BDP‐6 had no level, when the addition ratio of flame retardant was 8.03%. In the cone calorimeter test, the peak smoke production rate (pSPR) and total smoke production (TSP) of BDP‐6 were not significantly different from those of pure EP. In contrast, TSP and pSPR of 4N‐BDP‐6 decreased by 39.50% and 50.00% respectively compared with EP. Compared with BDP, 4N‐BDP shows better flame retardancy and smoke suppression performance, which can significantly improve the fire resistance of EP. The flame‐retardant mechanism of 4N‐BDP was resolved by scanning electron microscopy, XPS, and thermogravimetric analysis/infrared spectrometry. 4N‐BDP can increase the residual carbon rate of the composites, improve the residual carbon strength, play an excellent condensed phase flame retardant effect, and avoid further decomposition of the materials. In the gas phase, the decomposition of 4N‐BDP produces PO·, PO2· and NH3, which play a good quenching effect and dilution effect. The escape of NH3 will leave bubbles in the residual carbon, making the residual carbon more fluffy, further improving the ability of heat insulation and oxygen insulation, and enhancing the flame retardant effect of the condensed phase. In general, the flame‐retardant mechanism of 4N‐BDP is a synergistic combination of condensed phase and gas phase flame retardant mechanism. This work provides a new approach to improve the defects of organophosphorus flame retardant BDP commonly used in the market and enhance the fire resistance of EP.

Bio-inspired adenosine triphosphate-modified h-BN-based coral-like CuAl-LDH nanosheets as a functional green flame retardant to improve the fire safety of epoxy resins via catalyzing intumescent char formation

High flammability and fire toxicity are the biggest hindrances to further applications of epoxy resins (EP). In this work, we designed a novel “integrated” green intumescent flame retardant via bio-inspired adenosine triphosphate modification of h-BN-anchored coral-like CuAl-LDH nanosheets (mBN@LDH@PATP). Then, the mBN@LDH@PATP was used as a filler to improve the fire safety of EP. Specifically, the anisotropic heat transfer mode of h-BN can effectively promote the longitudinal barrier and lateral diffusion of heat. The coral-like CuAl-LDH can successfully promote the catalytic carbonization of pyrolytic volatiles and their adsorption. Furthermore, adenosine triphosphate (ATP) synergistically interacts with h-BN and CuAl-LDH to impart a high heat-stable intumescent char network to EP. As expected, mBN@LDH@PATP significantly improved the flame retardancy and smoke suppression of the EP nanocomposites. Compared with the control EP, the prepared mBN@LDH@PATP/EP showed a 43.3 %, 40.8 %, 36.5 % and 39.1 % decrease in PHRR, THR, PSPR and TSP, respectively. In addition, CO and CO2 yield were significantly reduced by 53.5 % and 57.5 %, while LOI (32.9 %) and UL-94 (V-0) were significantly improved. The enhanced fire safety of EP nanocomposites was confirmed by adequate characterization. This research offers a workable way to achieve efficient and environmentally friendly flame retardant polymers.

Preparation of a Novel Phosphorus–Nitrogen‐Containing Flame Retardant by Supramolecular Reaction and its Application in Epoxy Resin

Piperazine hexahydrate (PI) and diethylenetriamine penta(methylene phosphonic acid) (DTPMP) are used to synthesize flame‐retardant PI‐DTPMP through supramolecular reaction. The incorporation of PI‐DTPMP simultaneously improves the mechanical and flame‐retardant properties of epoxy resin (EP). With only 5 wt% loading of PI‐DTPMP, EP composites show excellent flame retardancy with a limiting oxygen index (LOI) of 36.4% and V‐0 rating in the UL‐94 test. The cone calorimetric test results demonstrates that the peak heat release rate, total heat release, and total smoke release of EP/5%PI‐DTPMP are reduced by 44.9%, 34.7%, and 37.7% compared with that of neat EP, respectively, owing to the formation of compact and insulating char layer during combustion. Moreover, EP/PI‐DTPMP composites show enhanced mechanical properties with the improved tensile and impact strength, as well as higher storage modulus, crosslink densities, and glass‐transition temperatures in dynamic mechanical analysis.

Preparation of Calcium Titanate Nanoparticles with Investigate the Thermal and Electrical Properties by Incorporating Epoxy

In recent years, the materials industry has begun to develop in the directions on enabling the effect of nanomaterials. Nanomaterials are one of the most basic materials that have helped in the development of industrial technology because of their unique properties. These properties make them spread in many areas, especially in the electrical and thermal. Still, traditional materials, at present, suffer from issues that restrict their use, such as thermal conductivity and electrical conductivity. Currently, nanomaterials owing to outstanding performance those traditional materials do not possess. In contrast, scientists have recently focused their efforts on increasing the (electrical and thermal) applications of epoxy resins. In this study, we combined nanoparticles (CaTiO3) with type epoxy resin (Quickmast 105) with different concentrations of CaTiO3 (0, 0.01, 0.02, 0.03, 0.04, 0.05 wt%) by casting. Several tests such as thermal conductivity, thermal expansion, electrical conductivity, dielectric constant and dielectric loss have been carried out. The test results showed a significant increase in thermal conductivity with increasing concentrations of nanoparticles in epoxy, decreasing thermal expansion by 28%, and increasing AC conductivity for all concentrations. The relative permittivity (dielectric constant) of epoxy nanocomposites remains nearly constant with increasing frequency. For dielectric loss, it can be seen that the epoxy nanocomposite's tan values are increasing also with high concentrations.

Synthesis of a Multielement Flame Retardant and Its Application in Epoxy Resin

For the purpose of obtaining flame-retardant epoxy resin (FREP) with exceptional comprehensive properties, a multielement flame retardant SVPM was synthesized by sulfathiazole, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), methylvinyldichlorosilane and vanillin. The effects of SVPM on the thermal stability, heat resistance, mechanical behavior and flame retardancy of epoxy resin (EP) were systematically revealed, and the flame-retardant mechanism of SVPM was deeply explored. In the presence of only 0.12 wt% phosphorus content in the system, FREP achieved V-0 rating of vertical combustion (UL-94) and the limiting oxygen index (LOI) value reached 31.1%. Additionally, SVPM reduced the smoke and heat release of EP. The mechanical properties of EP were enhanced by SVPM; specifically, the maximum increment of tensile strength and flexural strength of FREP were 26.23% and 16.67% respectively. The investigation of flame-retardant mechanism showed that the phosphorus-containing free radicals and SO2 decomposed by SVPM can quench the active free radicals in the combustion process, thus interrupting the chain reaction of combustion, and the noncombustible gas generated by SVPM during combustion can reduce the concentration of combustible volatiles. In the condensation phase, phosphoric acid and silicon dioxide produced by SVPM degradation can promote the stability and densification of the char layer, eventually effectively reducing the combustion intensity.