Effects of an (Intumescent flame retardant)‐montmorillonite combination on the thermal stability and fire‐retardant properties of LDPE/EVA nanocomposites

The combined effects of an organically modified montmorillonite (OMMT) and an intumescent flame retardant, poly (piperazine spirocyclic pentaerythritol bisphosphonate) (PPSPB), in (low‐density polyethylene)/[ethylene‐(vinyl acetate) copolymer] (LDPE/EVA) nanocomposites were observed. The results from X‐ray diffraction and transmission electron microscopy studies showed that exfoliated LDPE/EVA/PPSPB/OMMT nanocomposites were formed. Thermal stability and flammability properties were investigated by thermogravimetric analysis and cone calorimeter tests. The combination of PPSPB and montmorillonite improved thermal stability and reduced significantly the flammability, including peak heat release rate (PHRR), total heat release, average mass loss rate, etc. The PHRR of LDPE/EVA/PPSPB/OMMT was reduced by about 50% compared to that of an LDPE/EVA blend. The morphology and composition of the residues generated by cone calorimeter tests were investigated by scanning electronic microscopy (SEM) and energy dispersive X‐ray (EDX) analysis. The results of SEM showed that a compact and dense intumescent char was formed from the LDPE/EVA/PPSPB/OMMT nanocomposite upon combustion. The results of EDX examination revealed that the carbon content of this char was increased significantly by the combined effect of PPSPB and montmorillonite. J. VINYL ADDIT. TECHNOL., 19:285–292, 2013. © 2013 Society of Plastics Engineers     

Condensed‐phase flame retardation in nylon 6‐layered silicate nanocomposites: Films,fibers, and fabrics

Flame‐retardant properties of nylon 6/organically modified montmorillonite (OMMT) thin films, fibers, and fabrics were investigated to determine the efficacy of condensed‐phase flame‐retardant mechanism in relation to montmorillonite concentration, sample geometry, and flame test conditions. Horizontal flame spread conducted on thin films revealed no significant difference in burning behavior between nylon 6 and nanocomposites with 5 wt% OMMT. However, with a higher concentration level of 8–10 wt% OMMT, the films burned without any dripping. The flame spread rate was reduced by 30–40% as compared with nylon 6 films. Cone calorimeter study on nanocomposite films showed that the peak heat release rate of nylon 6 was reduced by 65–67% with 8–10 wt% OMMT. Undrawn nanocomposite monofilaments with 10 wt% OMMT burned slowly and steadily in Bunsen flame without dripping. In cone calorimeter, nanocomposite fabrics with 8 wt% OMMT showed reduced heat release rate and mass loss rate compared to nylon 6 fabrics with increase in fabric tightness factor. The mass loss rate was about 40–60% less when compared with nylon 6 fabrics. The fabric char structure remained intact after burning. This demonstrated the interdependence of fabric tightness factor, OMMT concentration, and source of heat flux in forming a protective char and affecting the flammability of fabrics. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Mechanical,thermal, and morphological properties of injection molded poly(lactic acid)/SEBS‐g‐MAH/organo‐montmorillonite nanocomposites

Poly(lactic acid)/organo‐montmorillonite (PLA/OMMT) nanocomposites toughened with maleated styrene‐ethylene/butylene‐styrene (SEBS‐g‐MAH) were prepared by melt‐compounding using co‐rotating twin‐screw extruder followed by injection molding. The dispersibility and intercalation/exfoliation of OMMT in PLA was characterized using X‐ray diffraction and transmission electron microscopy (TEM). The mechanical properties of the PLA nanocomposites was investigated by tensile and Izod impact tests. Thermogravimetric analyzer and differential scanning calorimeter were used to study the thermal behaviors of the nanocomposite. The homogenous dispersion of the OMMT silicate layers and SEBS‐g‐MAH encapsulated OMMT layered silicate can be observed from TEM. Impact strength and elongation at break of the PLA nanocomposites was enhanced significantly by the addition of SEBS‐g‐MAH. Thermal stability of the PLA/OMMT nanocomposites was improved in the presence of SEBS‐g‐MAH. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Pyrolysis and flammability behavior of long (Glass fiber)‐Reinforced polyamide 6 by aluminum alkylphosphinate‐based flame retardants in combination with organic montmorillonite

The pyrolysis and flammability behavior of long (glass fiber)‐reinforced polyamide 6 containing aluminum alkylphosphinate‐based flame retardant in conjunction with montmorillonite or organic montmorillonite (OMMT) were investigated by using thermal gravimetry, limiting oxygen index, vertical burning test, and cone calorimeter measurements. The results revealed that the incorporation of OMMT in (aluminum alkylphosphinate)‐containing long (glass fiber)‐reinforced polyamide 6 did not significantly affect the thermal stability; however, they showed an obvious synergy on the char yield. The components from the flame retardant, especially phosphorus, acted in the gas phase and condensed phase simultaneously. Substitution of part of flame retardants with OMMT helped keep more phosphorus in the solid phase at the expense of gas‐phase activity, as demonstrated in scanning electron microscopy‐energy‐dispersive X‐ray characterization of the residue. This substitution constructed an impermeable barrier on the burning surface, which was responsible for the improvements in the vertical burning test classification and limiting oxygen index test. J. VINYL ADDIT. TECHNOL., 24:27–36, 2018. © 2015 Society of Plastics Engineers     

Thermal and combustion behavior of ethylene‐vinyl acetate/aluminum trihydroxide/Fe‐montmorillonite composites

The flammability characterization and synergistic flame‐retardant effect of Fe‐montmorillonite (Fe‐OMT) in the ethylene‐vinyl acetate/aluminum hydroxide (EVA/ATH) compounds were studied using limiting oxygen index (LOI), UL‐94 test, cone calorimeter, microscale combustion calorimetry (MCC), and thermogravimetric analysis (TGA). The results showed that addition of Fe‐OMT increases the LOI value and improves the UL 94 rating. Cone calorimeter data indicate that the addition of Fe‐OMT greatly reduced the heat release rate and carbon monoxide production rate. Furthermore a compact char residue formed on the surface of the sample with a suitable of Fe‐OMT during the combustion. The MCC results indicate that addition of Fe‐OMT reduced the heat release rate and catalyzed the decomposition of EVA. The TGA data showed further evidence that Fe‐OMT can catalyze carbonization reactions. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Effect of organoclay in an immiscible poly(ethylene terephtalate) waste/poly(methyl methacrylate) blend

Blends of organically modified montmorillonite (OMMT) with poly(ethylene terephtalate) (PET) waste and poly(methyl methacrylate) (PMMA) were prepared by melt mixing. The morphology of PET/PMMA nanocomposites with different OMMT contents was characterized by transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The nonisothermal crystallization temperatures of nanocomposites were also examined by DSC. TEM observations and XRD patterns revealed that silicate layers were intercalated and well dispersed in the blend. Nanocomposites displayed better mechanical properties when compared with the unfilled blend. DMA analyses also showed efficient mixing of the two immiscible polymers and changes in glass transition temperature with the presence of OMMT. DSC analysis showed an enhancement in crystallization rate of nanocomposites and a decrease in cristallinity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Flammability and thermal characterization of PMMA/clay nanocomposites and thermal kinetics analysis

A detailed study of thermal stability of Poly (Methyl methacrylate)/layered silicate nanocomposites has been carried out in this work. Commercially modified nanoclays such as cloisite 30B (30B), cloisite 93A (C93A) and Na‐MMT and in‐house modified Na‐MMT were used as nanofiller in this study. All the systems were characterized by X‐ray diffraction, thermogravimetric analysis, differential scanning calorimetry, thermal conductivity. Investigations revealed the improved thermal properties of PMMA nanocomposites and the validity of Ozawa and Kissinger for the PMMA nanocomposites were also confirmed. Detailed study on thermal degradation kinetics using Ozawa and Kissinger model was carried out. The flammability of the materials has been investigated by cone calorimeter experiment, which showed reduced flammability of the nanocomposites. Formation of protective char layers during burning of nanocomposites was also observed through SEM analysis.POLYM. COMPOS., 33:2058–2071, 2012. © 2012 Society of Plastics Engineers     

A novel intumescent flame‐retardant system for flame‐retarded LLDPE/EVA composites

A new intumescent flame retardant (IFR) system consisting of ammonium polyphosphate (APP) and charing‐foaming agent (CFA) and a little organic montmorillonite (OMMT) was used in low‐density polyethylene (LLDPE)/ethylene‐vinyl acetate (EVA) composite. According to limiting oxygen index (LOI) value and UL‐94 rating obtained from this work, the reasonable mass ratio of APP to CFA was 3 : 1, and OMMT could obviously enhance the flame retardancy of the composites. Cone calorimeter (CONE) and thermogravimetric analysis (TGA) were applied to evaluate the burning behavior and thermal stability of IFR‐LLDPE/EVA (LLDPE/EVA) composites. The results of cone calorimeter showed that heat release rate peak (HRR‐peak) and smoke production rate peak (SPR‐peak) and time to ignition (TTI) of IFR‐LLDPE/EVA composites decreased clearly compared with the pure blend. TGA data showed that IFR could enhance the thermal stability of the composites at high temperature and effectively increase the char residue. The morphological structures of the composites observed by scanning electron microscopy (SEM) and X‐ray diffraction (XRD) demonstrated that OMMT could well disperse in the composites without exfoliation, and obviously improve the compatibility of components of IFR in LLDPE/EVA blend. The morphological structures of char layer obtained from Cone indicated that OMMT make the char layer structure be more homogenous and more stable. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synergistic effect of amino silane functional montmorillonite on intumescent flame‐retarded SEBS and its mechanism

A functional modified montmorillonite (F‐OMMT) was prepared by intercalating pristine montmorillonite using phosphonium salt and subsequent grafting through alkyl amino silane coupling. The synergistic effect of F‐OMMT on the flame retardancy and char‐forming mechanism of intumescent flame‐retarded polystyrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS) composite (SEBS/IFR) was investigated. When 2 wt % F‐OMMT was introduced to the SEBS/IFR composite, the limited oxygen index (LOI) value of the composite increased from 24.9% to 26.9%, and the peak heat release rate significantly reduced according to microscale combustion calorimeter (MCC) test. The outer char demonstrated that F‐OMMT produced dense and intact nanoparticles with a stabilised graphite structure. Meanwhile, F‐OMMT helped form a crosslinking network containing large amounts of P, O, N, and Si in the char layer. Along with IFR, the amino functional group on the clay released nonflammable ammonia in the gaseous phase, the enhanced blowing effect can overcome the high‐viscosity resistance of SEBS, more intumescent coating with strengthened clay platelets was then produced. In addition, the tensile properties of SEBS/IFR/F‐OMMT composite increased evidently for the good dispersion effect. F‐OMMT can serve as an effective and environmentally friendly additive for SEBS/IFR composite. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44953.     

Synthesis and properties of poly(methyl methacrylate)/clay nanocomposites using natural montmorillonite and synthetic Fe‐montmorillonite by emulsion polymerization

In this article, Fe‐montmorillonite (Fe‐MMT) was synthesized by hydrothermal method. For the first time, Fe‐MMT was modified by cetyltrimethyl ammonium bromide (CTAB), and poly(methyl methacrylate)(PMMA)/Fe‐MMT nanocomposites were synthesized by emulsion polymerization. Then poly(methyl methacrylate)(PMMA)/natural montmorillonite (Na‐MMT) and PMMA/Fe‐MMT nanocomposites were compared by Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD) patterns, transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA). By XRD and TEM, it was found out that the morphology of PMMA/Fe‐MMT nanocomposites was different from that of the PMMA/Fe‐MMT nanocomposites when the content of two types of clay was same in the PMMA matrix. It was possible that the presence of iron may lead to some radical trapping, which enhances intragallery polymerization to be developed to improve layer dispersion in PMMA/Fe‐MMT systems. In TGA curves, the thermal stability and residue at 600°C of PMMA/Fe‐MMT nanocomposites were higher than those of PMMA/Na‐MMT nanocomposites. Those dissimilarities were probably caused by structural Fe ion in the lattice of Fe‐MMT. POLYM. COMPOS., 27:49–54, 2006. © 2005 Society of Plastics Engineers     

Clay intercalation and influence on flammability and crystallization behaviors of POE‐based nanocomposites

Ethylene‐octene copolymer (POE)‐based nanocomposites were prepared from POE or maleic anhydride grafted POE with organo‐modified montmorillonite (OMT) using melt blending technique. Their morphology, flammability, and crystallization behavior were investigated by X‐ray diffraction (XRD), transmission electron microscopy (TEM), cone calorimeter, and differential scanning calorimetry (DSC). XRD and TEM studies confirmed the intercalation of clay layers within the POE matrix whereas the exfoliation throughout the maleated POE matrix. Cone calorimetry results exhibited that the reduction in heat release rate of exfoliated maleated‐POE/OMT nanocomposite was greater than that of intercalated POE/OMT nanocomposite. The DSC results suggested that the nonisothermal kinetics crystallization of the exfoliated nanocomposite corresponded to tridimensional growth with heterogeneous nucleation. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Preparation of aluminum hydroxide/aluminum phosphinate flame‐retardant poly(vinyl alcohol) foam through thermal processing

A novel flame‐retardant poly (vinyl alcohol) (PVA) composite foam was prepared successfully through thermal processing, which was filled with high content of flame retardant, based on aluminum hydroxide (ATH) and aluminum phosphinate (AlPi) and using water as plasticizer and blowing agent. The flame‐retardant property and mechanism of the prepared foam matrix were studied by vertical burning test, limiting oxygen index (LOI), cone calorimeter, scanning electronic microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). The experimental results showed that the PVA/ATH/AlPi (1/1.2/0.05) composite achieved LOI value of 41% and UL94 V‐0 (3.2 mm) rate. The addition of ATH and AlPi into PVA matrix significantly decreased flammability of the composites, because a more compact and continuous char layer of the PVA/ATH/AlPi composite could be formed, due to the involvement of AlPi in the char‐forming reaction. Compared with the pure PVA sample, the peak heat release rate (PHRR) and total heat release (THR) of PVA/ATH/AlPi (1/1.2/0.05) composite were reduced by 76.5% and 58.2%, respectively. Built upon this PVA‐based foam matrix with good flame retardancy, the flame‐retardant PVA‐based foam was successfully prepared through thermal extrusion. In addition, the influence of water content on melt viscosity, foam structure and mechanical strength was also analyzed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42020.     

Structural and ordering behavior of lamellar polystyrene‐block‐polybutadiene‐block‐polystyrene triblock copolymer containing layered silicates

Nanocomposites based on organically modified montmorillonites (OMMTs) and sodium montmorillonite (CLO‐Na⁺) with poly(styrene‐b‐butadiene‐b‐styrene) (SBS) diblock copolymer have been investigated. Solution blending of OMMT suspension in toluene with SBS and subsequent static casting and annealing resulted in transparent films. Final samples were processed by compression molding. The intercalation spacing in the nanocomposites, microphase separation of the SBS, and the degree of dispersion of nanocomposites were investigated by X‐ray diffraction (Wide and small‐angle X‐ray scattering), transmission optical microscopy (TOM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The increase of basal spacing of OMMT in the nanocomposites suggested the intercalation of SBS. The lamellar structure perfection was extensively affected by both OMMT. AFM images and TOM micrographs only showed well dispersed but not exfoliated nanocomposites. On the other hand, TEM showed inserted tactoids into both blocks depending on the surfactant used (stained samples) and the dispersion of those tactoids (unstained samples). Fourier transform infrared spectroscopy indicated only the presence of the OMMT into the SBS. Deviations of the decomposition pathway of pristine SBS with addition of the OMMT were found by thermogravimetric analysis. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation,thermal, and flammability of halogen‐free flame retarding thermoplastic poly(ether‐ester) elastomer/montmorillonite nanocomposites

In this article, the nanocomposites thermoplastic polyester‐ether elastomer (TPEE) with phosphorous–nitrogen (P–N) flame retardants and montmorillonite (MMT) was prepared by melt blending.The fire resistance of nanocomposites was analyzed by limiting oxygen index (LOI) and vertical burning (UL94) test. The result shows that the flame retardants containing P–N increased the LOI of the material from 17.3 to 27%. However, TPEE containing P–N flame retardants just got UL94 V‐2 ranking, which resulted in the flaming dripping phenomenon. On the other hand, TPEE containing P–N flame retardant and organic‐modified montmorillonite (o‐MMT) achieved UL94 V‐0 rating for the special microstructure. The XRD and TEM morphology has demonstrated that the formation of multi‐ordered structure regarding restricted segmental motions at the organic–inorganic interface and stronger interactions between the clay mineral layers and the polymer chains. The structure was supported by the results of rheological properties and DSC analysis. The thermal degradation and char residue characterization was studied by thermal gravimetric analysis (TGA) and SEM‐EDX measurements, respectively. The TGA and SEM‐EDX have demonstrated that o‐MMT results in the increase of char yield and the formation of the thermal stable carbonaceous char. POLYM. COMPOS., 37:700–708, 2016. © 2014 Society of Plastics Engineers     

Intumescent flame retardation of melamine‐modified montmorillonite on polyamide 6: Enhancement of condense phase and flame retardance

Melamine‐modified montmorillonite (MA‐MMT) was prepared via cation exchange. The intercalation behavior was investigated by Fourier transform infrared spectrometer (FT‐IR), X‐ray photoelectron spectroscopy (XPS), and X‐ray diffraction (XRD). The results showed that the d‐spacing value increased from 1.25 nm for Na‐montmorillonite (Na⁺MMT) to 1.53 nm for MA‐MMT. Different kinds of montmorillonite combined with melamine pyrophosphate (MPP) were used to prepare flame‐retardant polyamide 6 (FR‐PA6). Flame retardance of FR‐PA6 samples was investigated by limiting oxygen index (LOI), UL‐94 vertical burning method, and cone calorimeter test. Morphology and component of char residues for FR‐PA6 were investigated by scanning electron microscope (SEM) and XPS. It was found that MA‐MMT/MPP system contributed both excellent flame retardance and anti‐dripping ability for PA6. MA‐MMT particles can fill flaws of char residues and strengthen the char layer, leading to form more intumescent char layer. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

SEBS／蒙脱土复合材料结构与阻燃性能的研究

根据蒙脱土（MMT）特殊的片层结构,采用熔融插层法制备热塑性弹性体SEBS／蒙脱土插层复合材料。通过X射线衍射仪、透射电镜等表征手段研究复合材料的微观结构。使用锥形量热仪评价复合材料的燃烧性能。结果表明,有机蒙脱土（OMMT）片层的间距为1．948nm,SEBS／5％OMMT体系的片层间距为4．307nm,说明聚合物SEBS插入有机蒙脱土片层之间。SEBS／OMMT复合材料具有较低的热释放速率和质量损失速率,且随着OMMT添加量的增加,其热释放速率峰值降低愈明显。通过对复合材料的阻燃性能和微观结构的分析,探讨了其阻燃机理。     

Use of a new natural clay to produce poly(methyl methacrylate)‐based nanocomposites

Nanocomposites of poly(methyl methacrylate) (PMMA) filled with 3 wt% of modified natural Algerian clay (AC; montmorillonite type) were prepared by either in situ polymerization of methyl methacrylate initiated by 2,2′‐azobisisobutyronitrile or a melt‐mixing process with preformed PMMA via twin‐screw extrusion. The organo‐modification of the AC montmorillonite was achieved by ion exchange of Na⁺ with octadecyldimethylhydroxyethylammonium bromide. Up to now, this AC montmorillonite has found applications only in the petroleum industry as a rheological additive for drilling muds and in water purification processes; its use as reinforcement in polymer matrices has not been reported yet. The modified clay was characterized using X‐ray diffraction (XRD), which showed an important shift of the interlayer spacing after organo‐modification. The degree of dispersion of the clay in the polymer matrix and the resulting morphology of nanocomposites were evaluated using XRD and transmission electron microscopy. The resulting intercalated PMMA nanocomposites were analysed using thermogravimetric analysis and differential scanning calorimetry. The glass transition temperature of the nanocomposites was not significantly influenced by the presence of the modified clay while the thermal stability was considerably improved compared to unfilled PMMA. This Algerian natural montmorillonite can serve as reinforcing nanofiller for polymer matrices and is of real interest for the fabrication of nanocomposite materials with improved properties. Copyright © 2009 Society of Chemical Industry     

Preparation and structure and mechanical properties of poly(styrene‐b‐butadiene)/clay nanocomposites

Star‐shaped and linear block thermoplastic poly(styrene‐b‐butadiene) copolymer (SBS)/organophilic montmorillonite clays (OMMT) were prepared by a solution approach. The intercalation spacing in the nanocomposites and the degree of dispersion of nanocomposites were investigated by X‐ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The mechanical properties, dynamic mechanical properties, and thermal stability of these nanocomposites were determined. Results showed that SBS chains were well intercalated into the clay galleries and an intercalated nanocomposite was obtained. The mechanical strength of nanocomposites with the star‐shaped SBS/OMMT were significantly increased. The addition of OMMT also gave an increase of the elongation, the dynamic storage modulus, the dynamic loss modulus, and the thermal stability of nanocomposites. The increase of the elongation of nanocomposites indicates that SBS has retained good elasticity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3430–3434, 2004     

Relationship between the distribution of organo‐montmorillonite and the flammability of flame retardant polypropylene

This article studies the relationship between the distribution of organically modified montmorillonite (OMMT) and the flammability of flame retardant polypropylene which consists of polypropylene (PP), brominated epoxy resin‐antimony oxide (BER‐AO) and OMMT. Polypropylene‐graft‐maleic anhydride (PP‐g‐MAH) was used to increase the polarity of PP and aid the dispersion of OMMT. Two model systems, PP/BER‐AO/OMMT and PP/PP‐g‐MAH/BER‐AO/OMMT composites, have been prepared by melt blending. TEM studies reveal a significant change in the distribution of OMMT for these two systems. For the first composites, OMMT platelets are aggregated in the BER‐AO domains, whereas for the second composites, OMMT platelets are dispersed in the PP matrix. The flame retardant properties of the second composite reflected by UL 94 vertical burning test and cone calorimetry are better than that of the first one. When OMMT platelets aggregate in BER‐AO domains as in the first composite, the BER‐AO associated with OMMT may agglomerate into long ribbon‐like structures during burning, inducing uneven distribution of BER‐AO. As a result, loose and uneven residues are formed at the end of combustion. In comparison, OMMT platelets dispersed in polymer matrix are more efficient at stabilizing the polymer and preventing aggregation of BER‐AO during burning, which induce thick and uniform char layers at the end of combustion. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Flame‐retarding mechanism of organically modified montmorillonite and phosphorous‐Nitrogen flame retardants for the preparation of a halogen‐free,flame‐retarding thermoplastic poly(ester ether) elastomer

In this study, thermoplastic poly(ester ether) elastomer (TPEE) nanocomposites with phosphorus–nitrogen (P–N) flame retardants and montmorillonite (MMT) were prepared by melt blending. The fire resistance of the nanocomposites was analyzed by limiting oxygen index (LOI) and vertical burning (UL 94) tests. The results show that the addition of the P–N flame retardants increased the LOI of the material from 17.3 to 27%. However, TPEE containing P–N flame retardants only obtained a UL 94 V‐2 ranking; this resulted in a flame dripping phenomenon. On the other hand, TPEE containing the P–N flame retardant and organically modified montmorillonite (o‐MMT) achieved better thermal stability and good flame retardancy; this was ascribed to its partially intercalated structure. The synergistic effect and synergism were investigated by Fourier transform infrared spectroscopy and thermogravimetry. The introduction of o‐MMT decreased the inhibition action of the P–N flame retardant and increased the amount of residues. The catalytic decomposition effect of MMT and the barrier effect of the layer silicates are discussed in this article. The residues after heating in the muffle furnace were analyzed by scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and laser Raman spectroscopy. It was shown that the intercalated layer silicate structure facilitated the crosslinking interaction and promoted the formation of additional carbonaceous char residues in the formation of the compact, dense, folded‐structure surface char. The combination of the P–N flame retardant and o‐MMT in TPEE resulted in a better thermal stability and fire resistance because of the synergistic effect of the mixture. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41094.