Layer-by-layer assembled bagasse to enhance the fire safety of epoxy resin: A renewable environmental friendly flame retardant

In an effort to make rational use of resources, wasted bagasse were collected, and then fabricated by layer-by-layer (LbL) assembly to prepare an environmentally benign flame retardant for epoxy resin (EP). Six chitosan/ammonum polyphosphate bilayers were successfully deposited on the surface of bagasse, which endows EP/6BL@BF composites with a limiting oxygen index value of 24.1% and V-1 rating in UL-94 test. Compared with untreated bagasse, cone calorimetry test reveals that the incorporation of 6BL@BF reduces the peak heat release rate and total heat release by 64.6% and 13.2%, respectively. Besides, expandable graphite (EG) was combined with 6BL@BF to further enhance the fire safety and thermal stability of EP composites. Furthermore, the gas and condensed phase analysis of EP/6BL@BF/EG-3 composite was investigated by TG-IR, scanning electronic microscopy, Laser Raman spectroscopy, and X-ray photoelectron spectroscopy, and the flame retardant mechanism of 6BL@BF/EG was proposed. Finally, the mechanical properties of EP composites were investigated systematically.     

Thermal degradation kinetics,mechanical, and flame retardant properties of epoxy‐HDPE fabric‐clay composite laminates

Addition of particulates into laminates has been found to influence thermal and mechanical properties. Composite laminates of epoxy‐high density polyethylene (HDPE) fabric‐clay were prepared by reinforcing clay in the range of 0.1–0.7 phr into epoxy‐HDPE fabric laminates. These laminates are characterized for their mechanical, thermal, and flame retardant performances. With the addition of clay, an increase was found in impact resistance, tensile strength, flexural strength, and Young's modulus to an extent of 0.2 phr clay, after which there is a decrease in these properties. The thermal stability is found to decrease with the addition of clay. The improved mechanical properties are obtained at the slight expense of thermal stability. UL‐94 tests indicate a reduction in the burning rate. Morphology of the broken samples indicate better dispersion at lower clay load and tactoid formation at higher clay loading. These materials have potential applications in agriculture, construction, and decorative purposes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40751.     

Flame‐retardant mechanism of silica: Effects of resin molecular weight

The effects of resin molecular weight on the flame‐retardant mechanism of silica were studied with two different molecular weights of poly(methyl methacrylate) (PMMA), 122,000 and 996,000 g/mol, and two silicas, fused silica with a small surface area and silica gel with a large surface area. A total of six different samples were studied, with a mass fraction of 10% silica. The mass loss rate of the six samples in nitrogen and the heat release rate from burning in air were measured at an external radiant flux of 40 kW/m². The addition of silica gel to the low‐molecular‐weight PMMA significantly reduced the mass loss rate and heat release rate; addition to the high‐molecular‐weight PMMA provided the largest reductions of these quantities in this study. For fused silica, some reduction in mass loss rate and heat release rate was observed when it was added to the high‐molecular‐weight PMMA; addition to the low‐molecular‐weight PMMA did not reduce either loss rate. Chemical analysis of the collected residues and observation of the sample surface during gasification reveal the accumulation of silica near the surface; the larger its coverage over the sample surface was, less the mass loss rate and heat release rate were. Both the level of accumulation and its surface coverage depended strongly not only on the silica characteristics but also on the melt viscosity of the PMMA. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1541–1553, 2003     

Flame‐retardant properties and mechanisms of epoxy thermosets modified with two phosphorus‐containing phenolic amines

Two phosphorus‐containing phenolic amines, a 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO)‐based derivative (DAP) by covalently bonding DOPO and imine (SB) obtained from the condensation of p‐phenylenediamine with salicylaldehyde, and its analog (AP) via the addition reaction between diethyl phosphite and SB, were used to prepare flame‐retardant epoxy resins. The burning behaviors and dynamic mechanical properties of epoxy thermosets were studied by limited oxygen index (LOI) measurement, UL‐94 test, and dynamic mechanical analysis. The flame‐retardant mechanisms of modified thermosets were investigated by thermogravimetric analysis, Py‐GC/MS, Fourier transform infrared, SEM, elemental analysis, and laser Raman spectroscopy. The results revealed that epoxy thermoset modified with DAP displayed the blowing‐out effect during UL‐94 test. With the incorporation of 10 wt % DAP, the modified thermoset showed an LOI value of 36.1% and V‐0 rating in UL‐94 test. The flame‐retardant mechanism was ascribed to the quenching and diluting effect in the gas phase and the formation of phosphorus‐rich char layers in the condensed phase. However, the thermoset modified with 10 wt % AP only showed an LOI value of 25.7% and no rating in UL‐94 test, which was possibly ascribed to the mismatching of charring process with gas emission process during combustion. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43953.     

Synthesis and properties of a novel phosphorous‐containing flame‐retardant hardener for epoxy resin

An aryl phosphinate dianhydride 1,4‐bis(phthalic anhydride‐4‐carbonyl)‐2‐(6‐oxido‐6H‐dibenz[c,e][1,2]‐oxaphosphorin‐6‐yl)‐phenylene ester (BPAODOPE) was synthesized and its structure was identified by FTIR and ¹H‐NMR. BPAODOPE was used as hardener and flame retardant for preparing halogen‐free flame‐retarded epoxy resins when coupled with another curing agent. Thermal stability, morphologies of char layer, flame resistance and mechanical properties of flame‐retarded epoxy resins were investigated by thermogravimetric analysis, SEM, limiting oxygen index (LOI), UL‐94 test, tensile, and charpy impact test. The results showed that the novel BPAODOPE had a better flame resistance, the flame resistance and char yield of flame‐retarded epoxy resins increased with an increase of phosphorus content, tensile strength and impact strength of samples gradually decreased with the addition of BPAODOPE. The flame‐retarded sample with phosphorus contents of 1.75% showed best combination properties, LOI value was 29.3, and the vertical burning test reached UL‐94 V‐0 level, tensile strength and impact strength were 30.78 MPa and 3.53 kJ/m², respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Reactive organophosphorus flame retardant for transparency,low-flammability,and mechanical reinforcement epoxy resin

To maintain transparency and improve flame retardancy and mechanical properties of epoxy resin, a reactive organophosphorus flame retardant (DPDDM) was designed and synthesized, which was derived from 3,4-dihydroxybenzaldehyde, 4, 4′- diamino diphenylmethane and 9,10-dihydro-9-oxa –10- phosphaphenanthrene-10-oxidein two steps. Compared with neat epoxy resin (EP), the tensile strength and flexural strength of the EP with 5% DPDDM increased by 28.6% and 42.8%, respectively, indicating that DPDDM can significantly improve the mechanical properties of EP materials. Meanwhile, the DPDDM modified EP materials have good transparency and the EP with 5% DPDDM passed the V-0 rating and had the limiting oxygen index as high as 34%. Cone calorimeter test results showed that the heat release and smoke generation of the modified materials were significantly lower than the unmodified materials, which were reduced by 32.6% and 64.6%, respectively, indicating that the modified materials can greatly improve the safety of fire prevention. This work provides a new approach to prepare transparent epoxy resin with good mechanical properties and excellent flame retardancy.     

Transparent epoxy resin material with excellent fire retardancy enabled by a P/N/S containing flame retardant

An epoxy resin (EP) with excellent fire retardancy, good transparency, and satisfactory thermal stability has been obtained by introducing a new N/P/S containing flame retardant (HBD) into EP composites. When the phosphorus content was 0.48 wt%, EP/HBD reached V-0 rating with the limiting oxygen index of 33.5%. The cone calorimeter test (CC) indicated that the incorporation of HBD resulted in 1.5 times increase in ignition time, a 50% decrease in the maximum of heat release rates, 40% reduction of total heat release, and 50.7% decrease in total smoke production compared with EP. Besides, the fire-resistant behavior of EP/8% HBD is much better than the EP materials modified by similar P/N/S flame retardants reported in literature. The fire-retardant mechanism of HBD on EP was also analyzed by Raman, scanning electron microscope, Py-GC/MS, and Fourier transform infrared spectroscopy. The results show that HBD plays an important role in the formation of a dense intumescent carbon layer and gas phase quenching.     

Thermal polymerization of a brominated flame retardant in a glass‐fiber‐reinforced polypropylene—quantitative analysis

Pentabromobenzylacrylate (PBBA) is a possible candidate for use as a fire retardant (FR) in polypropylene (PP) composites. While PBBA imparts FR properties to the PP composite, it also affects adversely its mechanical properties. The FR may undergo thermal polymerization or grafting to the PP chains during processing. To study the effect of the different forms of FR (monomer, polymerized, or grafted) on composite properties, we have quantified the extent of FR polymerization and extent of grafting onto the PP chains. Fourier transform infrared microscopy was used in this work to determine the extent of polymerization and the spatial distribution of the FR. The latter was found to be homogeneous throughout the composite. Thermal polymerization of the FR during extrusion is varied mainly by the addition of an antioxidant. The grafting process of the FR onto PP depends on the degree of thermal polymerization, and therefore on the addition of antioxidant. The limiting value for grafting achieved at full polymerization is ～10% w/w. The grafted FR was found to have a significant effect on PP crystallinity, and hence it is expected to affect the mechanical properties as well. Bromine analysis indicates the FR has reacted with filler surfaces as well. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1506–1515, 2003     

Synthesis and performance of a novel nitrogen‐containing cyclic phosphate for intumescent flame retardant and its application in epoxy resin

A novel nitrogen‐containing cyclic phosphate (NDP) was synthesized and well characterized by ¹H, ¹³C, ³¹P NMR, mass spectra and elemental analysis. NDP was used as an additive intumescent flame retardant (AIFR) to impart flame retardancy and dripping resistance for diglycidyl ether of bisphenol‐A epoxy resin (DGEBA) curied by 4,4′‐diaminodiphenylsulfone (DDS) with different phosphorus content. The flammability, thermal stability, and mechanical properties of NDP modified DGEBA/DDS thermosets were investigated by UL‐94 vertical burning test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Izod impact strength and flexural property tests. The results showed that NDP modified DGEBA/DDS thermosets exhibited excellent flame retardancy, moderate changes in glass transition temperature and thermal stability. When the phosphorus content reached only 1.5 wt %, the NDP modified DGEBA/DDS thermoset could result in satisfied flame retardancy (UL‐94, V‐0). The TGA curves under nitrogen and air atmosphere suggested that NDP had good ability of char formation, and there existed a distinct synergistic effect between phosphorus and nitrogen. The flame retardant mechanism was further realized by studying the structure and morphology of char residues using FT‐IR and scanning electron microscopy (SEM). It indicated that NDP as phosphorus‐nitrogen containing flame retardant worked by both of the condensed phase action and the vapor phase action. Additionally, the addition of NDP decreased slightly the flexural strength of the flame retarded DGEBA epoxy resins, and increased the Izod impact strength of these thermosets. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41859.     

Property of intrinsic flame retardant epoxy resin cured by functional magnesium organic composite salt and diethylenetriamine

An efficient intrinsic flame retardants composite was prepared by curing epoxy resin with a functional magnesium organic composite salt (FMOCS, 0.685 ± 0.3 nm) and diethylenetriamine (DETA). Curing behavior, thermal and flame‐retardant properties of the cured epoxy resins were systematically investigated by infrared spectrum (FTIR), thermogravimetric analysis (TGA), vertical burning test (UL‐94) and limited oxygen index (LOI) measurement. It was found that flame retardancy and mechanical properties of the cured composite are significantly enhanced compared with DETA/EP. The LOI of the EP reached to 33%, which is much higher than the DETA/EP (19%) or its IFR composite (31%) in the optimal addition of ammonium polyphosphate (APP, 18.69 wt %), pentaerythritol (PER, 6.21 wt %) and FMOCS (3.50 wt %). Furthermore, the mechanical properties of the composite material measurement results to imply that it can enhance tensile strength (150%) and bending strength (88%) rather than DETA/EP, which were tested by impact testing machine and microcomputer control electron universal testing machines. Copyright © 2016 John Wiley & Sons, Ltd.     

A phosphorus‐containing inorganic compound as an effective flame retardant for glass‐fiber‐reinforced polyamide 6

A novel inorganic compound, aluminum hypophosphite (AP), was synthesized successfully and applied as a flame retardant to glass‐fiber‐reinforced polyamide 6 (GF–PA6). The thermal stability and burning behaviors of the GF–PA6 samples containing AP (flame‐retardant GF–PA6) were investigated by thermogravimetric analysis, vertical burning testing (with a UL‐94 instrument), limiting oxygen index (LOI) testing, and cone calorimeter testing (CCT). The thermogravimetric data indicated that the addition of AP decreased the onset decomposition temperatures, the maximum mass loss rate (MLR), and the maximum‐rate decomposition temperature of GF–PA6 and increased the residue chars of the samples. Compared with the neat GF–PA6, the AP‐containing GF–PA6 samples had obviously improved flame retardancy: the LOI value increased from 22.5 to 30.1, and the UL‐94 rating went from no rating to V‐0 (1.6 mm) when the AP content increased from 0 to 25 wt % in GF–PA6. The results of CCT reveal that the heat release rate, total heat release, and MLR of the AP‐containing GF–PA6 samples were lower than those of GF–PA6. Furthermore, the higher additive amount of AP affected the mechanical properties of GF–PA6, but they remained acceptable. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of water‐dispersed flame‐retardant polyurethane resin using phosphorus‐containing chain extender

In this research, a flame‐retardant water‐dispersed polyurethane resin was synthesized through incorporating phosphonate groups into the polyurethane structure in the chain‐extension step. A phosphorus‐containing reactive flame‐retardant compound was synthesized for this purpose. First, bis(4‐nitrophenyl)phenyl phosphine oxide was synthesized and then converted to bis(4‐amino phenyl)phenyl phosphine oxide (BAPPO) by reducing its nitro groups into amines. The obtained products were characterized by IR, ¹H‐NMR, and ³¹P‐NMR, and the thermal properties of the polymers were determined by DSC analysis. The BAPPO‐containing polyurethane showed physical properties that were almost similar to those of phosphorus‐free polyurethane and exhibited good flame resistance with a limiting oxygen index value of 27. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1314–1321, 2004     

Flame‐retardant epoxy resin from a caged bicyclic phosphate quadridentate silicon complex

The synergistic effects of phosphorus–silicon in a caged bicyclic phosphate quadridentate silicon complex (CPQS) on the flame retardancy of epoxy resin (EP) were studied with the limiting oxygen index, the UL‐94 test, thermogravimetric analysis, real time Fourier transform infrared spectroscopy, X‐ray powder diffraction, and scanning electron microscopy. The limiting oxygen index data, UL‐94 test, and thermogravimetric analysis results showed that the use of phosphorus and silicon together had a synergistic effect on the flame retardancy of EP. The Fourier transform infrared results and X‐ray powder diffraction measurements provided evidence that CPQS could promote the formation of char with silicophosphate and phosphocarbonaceous structures. The morphological structures observed by scanning electron microscopy demonstrated that more compact charred layers were formed in samples with CPQS than in those with 1‐oxo‐1‐phospha‐2,6,7‐trioxabicyclo[2.2.2]‐4‐hydroxymethyl octane and tetraethoxysilane. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Flame‐retardant cyanate ester resin with suppressed toxic volatiles based on environmentally friendly halloysite nanotube/graphene oxide hybrid

Development of high‐performance thermosetting resins by adding environmentally friendly flame retardant to heat‐resistant resins without deteriorating their outstanding thermal stability is an important research direction. Here, a unique hybrid (GHNT) consisting of graphene oxide (GO) and halloysite nanotubes (HNT) was synthesized, and then a series of composites based on cyanate ester (CE) resin were fabricated. The effects of GHNT on the heat resistance, flame retardancy, and smoke suppression of GHNT/CE composites were intensively investigated. The GHNT/CE composite with 5.0 wt % GHNT not only has about 15.1 °C higher initial degradation temperature, but also shows 54.6% or 37.9% lower peak heat release rate or maximum smoke density than CE resin. These results clearly demonstrate that GHNT is not the simple combination of GO and HNT; instead, it obviously shows positive synergistic effects in simultaneously improving the flame retardancy and thermal resistance of CE resin. The improved flame retardancy could be attributed to condensed‐phase mechanisms, including increasing char yield, building a dense char layer, and free radical scavenging. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46587.     

Novel strategy for molybdenum disulfide nanosheets grown on titanate nanotubes for enhancing the flame retardancy and smoke suppression of epoxy resin

A novel hybrid consisting of a molybdenum disulfide (MoS₂) coating on a titanium dioxide nanotube (TNT) surface (MoS₂–TNT) was synthesized by a hydrothermal method. The MoS₂, TNTs, and MoS₂–TNT hybrid were incorporated into epoxy resin (EP) to study their effects on its thermal performance and flame retardancy. Thermogravimetric analysis results show that the char yield at 700 °C of EP–MoS₂–TNTs was obviously increased compared with that of the EP–MoS₂ or EP–TNTs; this indicated that MoS₂–TNTs had a good carbonization effect. The limiting oxygen index, cone calorimetry, and smoke density tests showed that MoS₂–TNTs effectively improved the flame retardancy and smoke suppression of EP. This was attributed to the physical barrier effect of MoS₂ and the adsorption of TNTs. Moreover, the flame retardancy and smoke suppression of the EP–MoS₂–TNTs were better than those of the EP–MoS₂ or EP–TNTs alone with the same amount of addition; this indicated that there was a synergistic effect between MoS₂ and TNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46064.     

Melamine polyphosphate/silicon‐modified phenolic resin flame retardant glass fiber reinforced polyamide‐6

The halogen‐free flame retardance of glass fiber reinforced polyamide‐6 (PA6) is an everlastingly challenge due to well‐known wick effect. In this research, a novel system composed of a nitrogen–phosphorous flame retardant, melamine polyphosphate combined with a macromolecular charring agent, silicon‐modified phenolic resin (SPR), was employed to flame‐retard glass fiber reinforced PA6. It exhibited obvious synergistic effect between the two components at a proper ratio range. The flame retardance of the composites can be remarkably improved due to the increased amount and improved thermal stability of the produced char. The flame resistance tests indicated that the synergism system with an optimized ratio achieved V0 (1.6 mm) rating of UL94, 25.2% of Limited Oxygen Index, and only 338.2 W/g of the heat release peak rate. The corresponding synergistic mechanisms were investigated by the characterizations including the thermal gravimetric analysis, carbonation test, and the char morphology observation. It confirmed that the introduced SPR could accelerate the carbonation of PA6 resin, which was in favor of the construction of denser and more continuous charring structure. In addition, the flame retardant materials also indicated the acceptable mechanical properties, showing the advantages in the overall performance. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Flame‐retardant behavior of a phosphorus/silicon compound on polycarbonate

A phosphorus/silicon flame retardant, MVC‐DOPO, was synthesized from 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and 2,4,6,8‐tetra‐methyl‐2,4,6,8‐tetra‐vinyl‐cyclo‐tetrasiloxane (MVC) via addition reaction. Its flame‐retardant effect on polycarbonate (PC) was investigated. The phosphorus/silicon flame retardant increased the limited oxygen index and UL‐94 rating and reduced the heat release rate and total heat release of DOPO‐MVC/PC composites during combustion, indicating the excellent flame‐retardant effect of MVC‐DOPO on PC. MVC‐DOPO inhibited the burning intensity of PC material in the gaseous phase and promoted the formation of a more viscous residue in the condensed phase. Through releasing phosphorus‐containing pieces and phenoxy radicals from the phosphaphenanthrene group, MVC‐DOPO quenched the combustion chain reaction in the gaseous phase; through promoting formation of a more viscous residue and a dense char layer from the main actions of the cyclotetrasiloxane group, MVC‐DOPO reduced fuel release and generated a barrier effect in the condensed phase. Hence, MVC‐DOPO effectively exerted a flame‐retardant effect on PC material in both the gaseous and condensed phases during combustion. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45815.     

Joint flame‐retardant effect of triazine‐rich and triazine/phosphaphenanthrene compounds on epoxy resin thermoset

To obtain a more efficient flame‐retardant system, the extra‐triazine‐rich compound melamine cyanurate (MCA) was coworked with tri(3‐9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide‐2‐hydroxypropan‐1‐yl)?1,3,5‐triazine‐2,4,6‐trione (TGIC–DOPO) in epoxy thermosets; these were composed of diglycidyl ether of bisphenol A (DGEBA) epoxy resin and 4,4′‐diaminodiphenyl methane (DDM). The flame‐retardant properties were investigated by limited oxygen index measurement, vertical burning testing, and cone calorimeter testing. In contrast to the DGEBA/DDM (EP for short) thermoset with a single TGIC–DOPO, a better flame retardancy was obtained with TGIC–DOPO/MCA/EP. The 3% TGIC–DOPO/2% MCA/EP thermoset showed a lower peak heat‐release rate value, a lower effective heat of combustion value, fewer total smoke products, and lower total yields of carbon monoxide and carbon dioxide in comparison with 3% TGIC–DOPO/EP. The results reveal that MCA and TGIC–DOPO worked jointly in flame‐retardant thermosets. The dilution effect of MCA, the quenching effect of TGIC–DOPO, and their joint action inhibited the combustion intensity and imposed a better flame‐retardant effect in the gas phase. The 3% TGIC–DOPO/2% MCA/EP thermoset also exhibited an increased residue yield, and more compositions with triazine rings were locked in the residues; this implied that MCA/TGIC–DOPO worked jointly in the condensed phase and promoted thermoset charring. The results reveal the better flame‐retardant effect of the MCA/TGIC–DOPO system in the condensed phase. Therefore, the joint incorporation of MCA and TGIC–DOPO into the EP thermosets increased the flame‐retardant effects in both the condensed and gas phases during combustion. This implied that the adjustment to the group ratio in the flame‐retardant group system endowed the EP thermoset with better flame retardancy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43241.     

Synthesis and characterization of epoxy film cured with phosphorous‐containing phenolic resin

Through the electrophilic addition reaction of ? P(O)? H and C?C, a series of novel phosphorus‐containing phenolic resins bearing maleimide (P‐PMFs) were synthesized and used as curing agent for preparing high performance and flame retardancy epoxy resins. The structure of the resin was confirmed with FTIR and elemental analysis. Thermal properties and thermal degradation behaviors of the thermosetted resin was investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The epoxy resins exhibited high glass transition temperature (143–156°C), goof thermal stability (>330°C) and retardation on thermal degradation rates. High char yields (700°C, 52.9%) and high limited oxygen indices (30.6–34.8) were observed, indicating the resins' good flame retardance for the P‐PMFs/CNE cured resins. The developed resin may be used potentially as environmentally preferable products in electronic fields. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3813–3817, 2007     

Intrinsic flame-retardant epoxy resin composites with benzoxazine: Effect of a catalyst and a low curing temperature

Three kinds of inherent flame-retardant epoxy resin (EP) composites with 20 wt % benzoxazine (BOZ) were prepared with different curing processes with 2-methyl-1H-imidazole (MI) as a catalyst or/and changes in the curing temperature. The effects of the curing process on the flame retardancy, thermal stability, mechanical properties, and curing behaviors were investigated. The composite with added MI cured at low temperature (EBM–LT) had the best properties. It possessed a 35.3% limiting oxygen index and achieved a UL 94 V-0 rating. Thermogravimetric analysis indicated that EBM–LT had the best thermal stability among the three kinds of EP composites with BOZ. The EP composites with BOZ mainly displayed a condensed-phase flame-retardant mechanism. The mechanical properties improvement was attributed to the formation of a heterogeneous network. Differential scanning calorimetry indicated that MI reacted with EP and catalyzed the homopolymerization of BOZ, and EP reacted with BOZ. Fourier transform infrared spectroscopy analysis indicated that curing at lower temperature caused the formation of more homopolymers of BOZ. The relationship of the curing process, network structure, and properties of EP composites with BOZ was established; this could help with the design of high-performance EP composites with BOZ. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47847.