Novel intumescent flame retardants: synthesis and application in polycarbonate

Novel phosphorus‐containing and nitrogen‐containing intumescent flame retardants, bis‐aminobenzyl spirocylic pentaerythritol bisphosphonate (BASPB) and arylene‐N,N′‐bis(2,2‐dimethyl‐1,3‐propanediol phosphoramidate) (ABDPP), were synthesized, and their structures were characterized with Fourier transform infrared spectroscopy and ¹H and ³¹P nuclear magnetic resonance. The phosphorus compounds were used to impart flame retardancy to polycarbonate (PC). Combustion behaviors and thermal degradation properties of the flame‐retarded‐PC composites were assayed by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test, and thermogravimetric analysis. PC/5 wt.% BASPB and PC/5 wt.% ABDPP composites passed UL‐94 V‐0 rating; their LOI values were 35.5% and 34.7%, respectively. Scanning electron microscopy revealed that the char properties had crucial effects on the flame retardancy. The mechanical properties and water resistance of the PC/BASPB and PC/ABDPP composites were also measured. After water resistance test, PC/5 wt.% BASPB and PC/5 wt.% ABDPP composites kept V‐0 rating, and the mass loss was only 1.0%. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis of a novel char-forming agent (PEIC): Improvement in flame retardancy,thermal stability,and smoke suppression for intumescent flame-retardant polypropylene composites

A novel char-forming agent named PEIC was designed and synthesized combining pentaerythritol octahydrogen tetraphosphate (PEPA) and tris(2-hydroxyethyl) isocyanurate. PEIC was combined with the silica-gel-microencapsulated ammonium polyphosphate (OS-MCAPP), preparing intumescent flame-retardant polypropylene (PP) composites. The results of the limiting oxygen index (LOI) show that the composite containing 30 wt % IFR with OS-MCAPP:PEIC = 2:1 presents the optimal LOI of 32.7%. Meanwhile, the cone calorimeter tests show that its peak heat release rate is 432 kW m⁻², which decreases by 62.1% compared with that of pure PP, showing a high-efficient flame retardancy. The exhibited UL-94 V-0 rating for all the composites indicates that the IFR composed of PEIC and OS-MCAPP has high-efficient flame retardancy in PP. The analysis of residue char reveals that PEIC could improve the quality of char in compactness, intumescentia, and the degree of graphitization. Further, the effect of IFR on the mechanical properties of PP composites was also evaluated and discussed. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48296.     

An easy‐to‐obtain silicone‐containing flame retardant and its effects on the combustion of polycarbonate

A novel silicone‐containing flame retardant (HSOBA) synthesized from hydrogen‐containing silicone oil and Bisphenol A via a simple approach has been incorporated into polycarbonate (PC) matrix to study its effects on the flame retardancy. The flame retardancy of PC/HSOBA composites is investigated by limiting oxygen index (LOI), vertical burning tests (UL‐94), and cone calorimeter measurement. The LOI value of the composites is 31.7 and the UL‐94 rating reaches V‐0, when the content of HSOBA is 3 wt %. Cone calorimeter data confirm that the HSOBA acts as an effective additive functioning both as flame retardants and as smoke suppressant. Evolution of the thermal behaviors of the composites tested by TGA, the morphological structures, and the constituent of char residue after LOI tests characterized by scanning electronic microscopy‐energy‐dispersive X‐ray analysis were used to explain the possible flame‐retardant mode. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mechanical,thermal properties,and flame retardancy of PC/ultrafine octaphenyl‐POSS composites

Composites of ultrafine polyhedral oligomeric octaphenyl silsesquioxane (OPS) and polycarbonate (PC) were prepared by melt blending. The mechanical and thermal properties of the composites were characterized by tensile and flexural tests, impact test, differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), and thermal gravimetric analysis (TGA). Rheological properties of these melts were tested by torque rheometer. The flame retardancy of the composites was tested by limiting oxygen index (LOI), the vertical burning (UL‐94), and cone calorimeter test. The char residue was characterized by scanning electron microscope (SEM) and ATR‐FTIR spectrum. Furthermore, the dispersion of OPS particles in the PC matrix was evidenced by SEM. The results indicate that the glass transition temperatures (T_g) and torque of the composites decrease with increasing OPS loading. The onset decomposition temperatures of composites are lower than that of PC. The LOI value and UL‐94 rating of the PC/OPS composites increase with increasing loading of OPS. When OPS loading reaches 6 wt %, the LOI value is 33.8%, UL‐94 (1.6 mm) V‐0 rating is obtained, and peak heat release rate (PHRR) decreases from 570 to 292 kJ m^?2. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of a phenylene phenyl phosphine oligomer and its flame retardancy for polycarbonate

A novel flame retardant, phenylene phenyl phosphine oligomer (PPPO) was synthesized and its chemical structure was characterized using Fourier transform infrared spectroscopy, ¹H, ¹³C, ³¹P nuclear magnetic resonance spectroscopy and mass spectrometer. PPPO was used to impart flame retardancy to polycarbonate (PC). Combustion behaviors and thermal degradation properties of PC/PPPO system were assayed by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test, and thermogravimetric analysis. PC/6 wt % PPPO passed UL‐94 V‐0 rating with 3.0 mm samples and the LOI value was 34.1%, and PC/8 wt % PPPO also passed UL‐94 V‐0 rating with 1.6 mm samples and the LOI value was 36.3%. Scanning electron microscopy reveals that the char properties had crucial effects on the flame retardancy of PC. Mechanical properties and water resistance of PC/PPPO system were also measured. After water resistance test, PC/6 wt % PPPO with 3.0 mm samples and PC/8 wt % PPPO with 1.6 mm samples kept V‐0 rating and mass loss was only 0.2%. The results revealed that PPPO was an efficient flame retardant for PC. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Comparative study on flame retardancy and thermal degradation of phosphorus- and silicon-containing epoxy resin composites

Epoxy composites containing phosphorus and/or silicon were prepared using polyphenylmethoxysilicone (PPMS) and microencapsulated ammonium polyphosphate (MFAPP) as modifiers. Siliconized epoxy copolymer (EPMS) was obtained via the polycondensation of PPMS and diglycidyl ethers of bisphenol A (DGEBA) type epoxy resin. Then MFAPP was added into EPMS or DGEBA based hybrids respectively to improve their flame retardancy further. Thermal and flame retardant properties of EPMS/MFAPP and DGEBA/MFAPP composites were evaluated by Limited Oxygen index (LOI), UL-94 test and thermogravimetric analysis (TGA). The higher LOI value and UL-94 rating confirmed that MFAPP was an effective flame retardant in DGEBA compared with EPMS. A remarkable synergistic effect of phosphorus and silicon on flame retardation of EPMS/MFAPP was not observed. The reason was that the flame retardancy of epoxy composites containing phosphorus was based on solid phase. FTIR spectra of the char residue showed that when MFAPP was added, without sufficient O-H groups in EPMS/MFAPP, an effective insulative layer which protects underlying materials can’t form during combustion.     

Effects of platinum compounds/superfine aluminum hydroxide/ultrafine calcium carbonate on the flame retardation and smoke suppression of silicone foams

Environmentally friendly, flame-retardant, and relatively low-density (0.25–0.31 g cm⁻³) silicone foams (SiFs) were successfully obtained through dehydrogenation at room temperature (RT = 25.0 °C). Moreover, a flame-retardant system for SiFs was obtained through a synergistic combination of platinum (Pt) compounds, superfine aluminum hydroxide (ATH), and ultrafine calcium carbonate (CC). The smoke suppression, flame retardance, mechanical properties, and thermal stability of SiFs with Pt compounds, ATH, and CC were tested using the limited oxygen index (LOI), UL-94 test, smoke density test, cone calorimeter, and thermogravimetry–Fourier transform infrared spectroscopy. With only 0.6 wt % Pt compounds, the pure SiF achieved the UL-94-V1 rating (3 mm thick), had an LOI value of 29.6%, and the maximum smoke density (MSD) was 6.5%. After adding ATH and CC, SiF composites could achieve the UL-94-V0 rating (3 mm thick), the LOI increase to 35.2%, and MSD decrease by 45%. Furthermore, the SiF with 0.6 wt % Pt compounds, 15.0 wt % ATH, and 15.0 wt % CC exhibited the optimal comprehensive properties for smoke suppression, flame retardance, mechanical performance, and thermal stability. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47679.     

Synergistic Effects of Nanoporous Nickel Phosphates VSB-1 on an Intumescent Flame-Retardant Low-Density Polyethylene (LDPE) System

Nanoporous nickel phosphates VSB-1 was synthesized by hydrothermal method, and its structure was characterized by X-ray diffraction (XRD), thermogravimetric analyses (TGA) and high resolution transmission electron microscopy (HRTEM). The flame retardancy and thermal behaviour of intumescent flame retardants (IFR) with and without VSB-1 for low-density polyethylene (LDPE) were evaluated by LOI, UL-94 burning test, TGA and cone calorimeter test. With the addition of 2 wt% VSB-1 to LDPE/IFR systems, the LOI value increases from 28.7 to 31, and UL-94 rating raises from V-1 rating to V-0 rating. The results of cone calorimeter show that heat release rate (HRR) peak decrease substantially from 511 KW/m² to 407 KW/m² with 2 wt% VSB-1 in LDPE/IFR systems. The scanning electron microscopy (SEM) indicates the quality of char forming of LDPE/IFR/ VSB-1 is superior to that of LDPE/IFR.     

Crosslinking of β-cyclodextrin and combining with ammonium polyphosphate for flame-retardant polypropylene

This work presents the synthesis of crosslinked hexamethylene diisocyanate β-cyclodextrins (HDI-CDs) by reacting β-cyclodextrin (β-CD) with HDI as a crosslinking agent at different feed ratios. As a novel char-forming agent, the HDI-CDs are combined with ammonium polyphosphate (APP) and applied in polypropylene (PP) to form intumescent flame-retardant composites. The structure of HDI-CDs is characterized by Fourier transform infrared spectra (FTIR), ¹³C nuclear magnetic resonance spectroscopy, and nitrogen adsorption–desorption test. The thermogravimetric analysis (TGA) results indicate that HDI-CDs have better char-forming performance than β-CD. FTIR spectra, X-ray diffraction, and Raman spectra characterization demonstrate that the reaction between HDI-CDs and APP contributes to the formation of a more stable char layer than β-CD and APP. According to the results of TGA, scanning electron microscopy, limiting oxygen index (LOI), UL-94, and X-ray photoelectron spectroscopy test, when the crosslinking degree of HDI-CDs is high enough (not less than β-CD:HDI = 1:3.6), the PP/APP/HDI-CDs composites can form a compact and dense char layer during combustion. Among all composites, PP/APP/HDI-CD(4) shows the best flame-retardant performance, which can pass the UL 94 V-0 rating with an LOI value of 32.8% when the loading of flame retardants is 28 wt %. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48320.     

In situ polymerization of flame retardant modification polyamide 6,6 with 2-carboxy ethyl (phenyl) phosphinic acid

A novel halogen-free flame retardant copolyamide 6,6 (FR-PA66) was prepared successfully by in situ polymerizing with adipic acid hexamethylene salt and 2-carboxy ethyl (phenyl) phosphinic acid (CEPPA). The elemental composition and chemical structure of FR-PA66 were characterized by energy dispersive X-ray spectroscopy, Fourier transform infrared spectrometer and ¹³C Nuclear magnetic resonance spectrometer. The flame retardancy, thermal stability, and morphology of char residues were also investigated by the limiting oxygen index (LOI), UL 94 test, thermogravimetric analysis, and scanning electron microscopy. The results showed that FR-PA66 samples had much better flame retardancy and char formation ability than pure PA66 after the flame retardant modification. The LOI values were increased from 24.0 to 28.0% by adding 6 wt % of CEPPA and all FR-PA66 samples were rated as V-0 rating in UL-94 test. Furthermore, the thermal stability analysis indicated that in situ polymerization with CEPPA effectively decreased the initial decomposition temperature and increased the amount of char residue. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48687.     

Flame retardant performance of a carbon source containing DOPO derivative in PET and epoxy

The combination of gas‐phase and condensed‐phase action will contribute to high quality flame retardant. A novel 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO)‐based flame retardant (DOPO‐DOPC), which contains carbon source was synthesized in favor of conducting the effect of gas‐phase as well as promoting the char formation in condensed‐phase. The chemical structure of DOPO‐DOPC was characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). DOPO–DOPC was used as an additive in poly(ethylene terephthalate) (PET) and epoxy resin (EP). The flame retardancy of PET/DOPO‐DOPC and EP/DOPO‐DOPC composites were studied by limiting oxygen index (LOI) and UL‐94 test. The results showed that the incorporation of DOPO–DOPC into PET or EP could obviously improve their flame retardancy. The LOI values of modified PET or EP, which contained 10 wt % DOPO‐DOPC reached 42.8 and 31.7%, respectively. The thermogravimetric analysis (TGA) results revealed that DOPO–DOPC enhanced the formation of char residues. The Laser Raman spectroscopy (LRS) was used to investigate the carbon structure of thermal oxidation residues. Because of the combination of the gas phase flame retardant effect of DOPO moiety and the promoting formation of char residues in condensed phase, the PET and EP composites exhibited significant improvement toward flame retardancy. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44639.     

Vinyl polysiloxane microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

Vinyl polysiloxane microencapsulated ammonium polyphosphate (MAPP) was prepared by a sol-gel method using vinyltrimethoxysilane as a precursor to improve its thermal stability and hydrophobicity. The MAPP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and thermogravimetric analyzer (TGA). The results showed that ammonium polyphosphate (APP) was successfully coated with vinyl polysiloxane. MAPP and pentaerythritol (PER) were used together to improve the flame retardancy of polypropylene (PP). The flame retardant properties of PP composites were investigated by limiting oxygen index (LOI), UL-94 test, TGA and SEM. When the MAPP was added as a flame retardant, with PER as a char forming agent, the LOI of PP/MAPP/PER composites was 33.1%, and it reached the UL-94 V-0 level. The results also demonstrated that the flame retardant properties of PP/MAPP/PER composites were better than those of PP/APP/PER composites at the same loading. Moreover, the addition of flame retardant and carbon forming agent could promote the crystallization behavior of PP.     

硅酮粉协同膨胀阻燃剂阻燃HIPS研究

通过熔融共混制备硅酮粉(GM)协同膨胀阻燃剂(IFR)阻燃的高抗冲聚苯乙烯(HIPS)复合材料,并通过红外光谱、扫描电子显微镜、热重分析、X射线衍射以及电子拉力机等对材料和残炭进行表征.结果表明:与只加入IFR相比,GM的加入能明显提升阻燃材料的力学性能,改善IFR与HIPS的相容性,有效提高HIPS的阻燃性能.当加入...     

Synthesis of a bio-based triazine derivative and its effects on flame retardancy of polypropylene composites

A triazine derivative CC–Cy was synthesized using cytosine (Cy) and cyanuric chloride (CC). The CC–Cy was used as a charring agent and combined with ammonium polyphosphate (APP) to form an intumescent flame-retardant (IFR) system. The IFR system was applied to improve the flame retardancy of polypropylene (PP). Moreover, bisphenol-A bis(diphenyl phosphate) (BDP) was introduced in the IFR system to regulate the suitability between the IFR and PP. The results showed the PP containing 20 wt % APP and 5 wt % CC–Cy achieves the UL-94 V-2 rating. While the PP with 18 wt % APP/CC-Cy (4:1) and 3 wt % BDP obtains the UL-94 V-0 rating indicating the improved flame-retardant efficiency. Thermal degradation behaviors and char morphology both showed that the reactions between APP and CC–Cy promote the formation of char residues, and BDP works in gas phase to enhance the flame retardancy of PP composites. Thus, a synergistic IFR system based on APP, CC–Cy, and BDP is formed, which can protect PP from fire effectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47367.     

Flame retardant and antibacterial properties of PLA/PHMG-P/APP composites

Poly(lactic acid) (PLA) has evolved into a commodity polymer with numerous applications. However, its high flammability limits its viability as a perfect alternative to petrochemical engineering plastics. In this study, PLA was modified using polyhexamethyleneguanidine phosphate (PHMG-P) and ammonium polyphosphate (APP). The flame retardant performance of PLA/PHMG-P/APP was investigated based on the limiting oxygen index (LOI), vertical burning test (UL-94), thermogravimetric analysis (TGA), cone calorimetry (CC), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and Raman Spectrometry. Qualitative and quantitative methods were used to determine the antibacterial properties of PLA composites. The LOI of PLA-10% (P:A = 1:4) was 31.7% and was rated V-0 in the UL-94 V-0 test. The antibacterial properties of the composites reflected the antibacterial effects of PLA-10% (P: A = 1:4) against Escherichia coli and Staphylococcus aureus, with the antibacterial rates reaching 93.41% and 93.26%, respectively. PHMG-P and APP had a synergistic flame-retardant effect and improved the flame retardancy of PLA while exhibiting excellent antibacterial properties.     

Synthesis of a novel flame retardant containing phosphorus and sulfur and its application in polycarbonate

A novel flame retardant containing phosphorus and sulfur, bis(2‐tienyl)phenylphosphine (BTPP) was synthesized and characterized with Fourier transform infrared spectroscopy, ¹H, ¹³C, and ³¹P nuclear magnetic resonance. BTPP was used to impart flame retardancy to polycarbonate (PC). Combustion behaviors and thermal degradation properties of PC/BTPP system were assayed by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test, and thermogravimetric analysis. PC/3 wt% BTPP passed UL‐94 V‐0 rating with 3.0 mm samples and the LOI value was 36.5%. PC/6 wt% BTPP passed UL‐94 V‐0 rating with 1.6 mm samples and the LOI value was 38.5%. Scanning electron microscopy revealed that char properties had direct effects on the flame retardancy. Mechanical properties and water resistance of PC/BTPP system were also examined. After water resistance test, PC/3 wt% BTPP with 3.0 mm samples and PC/6 wt% BTPP with 1.6 mm samples kept V‐0 rating and mass loss were only 0.2%. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Enhanced mechanical and flame-resistant properties of polypropylene nanocomposites with reduced graphene oxide-functionalized ammonium polyphosphate and pentaerythritol

A novel functionalized graphene oxide grafted by ammonium polyphosphate (GO-APP) was synthesized through acylating chlorination method to improve the flame retardancy and mechanical properties of polypropylene (PP) nanocomposites in combination with pentaerythritol (PER). During the mixing process, GO-APP nanosheets were thermally reduced and PP/rGO-APP/PER composites were finally obtained. In comparison, PP/rGO-APP/PER composites exhibit better mechanical, thermal, and flame-retardant performances than those of PP/APP/PER composites when containing the same loading of total additives. PP/APP/PER 30 wt % composite only passes V-1 rating in vertical burning tests (UL-94), whereas PP/rGO-APP/PER 25 wt % composite ranks V-0 rating. Furthermore, PP/rGO-APP/PER 30 wt % composite reaches the highest limiting oxygen index (LOI) value of 31.2%, and its impact strength is almost three times higher than pure PP. The improvement in the fire safety is mainly due to the enhanced char yield, and the “tortuous path” effect caused by intercalate-exfoliated structures formed in PP/rGO-APP/PER composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48036.     

Synthesis of a novel phosphonate flame retardant and its application in epoxy resins

A novel phosphonate flame retardant additive bis(2,6‐dimethyphenyl) phenylphosphonate (BDMPP) was synthesized from phenylphosphonic dichloride and 2,6‐dimethyl phenol, and its chemical structure was characterized by Fourier transform infrared (FTIR) spectroscopy, ¹H and ³¹P nuclear magnetic resonance. The prepared BDMPP and curing agent m‐phenylenediamine were blended into epoxy resins (EP) to prepare flame retardant EP thermosets. The effect of BDMPP on fire retardancy and thermal degradation behavior of EP/BDMPP thermosets was investigated by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter and thermalgravimetric analysis (TGA). The morphologies of char residues of the EP thermosets were investigated by scanning electron microscopy (SEM) and the water resistant properties of thermosets were evaluated by putting the samples into distilled water at 70°C for 168 h. The results demonstrated that the cured EP/14 wt % BDMPP composites with the phosphorus content of 1.11 wt % successfully passed UL‐94 V‐0 flammability rating and the LOI value was as high as 33.8%. The TGA results indicated that the introduction of BDMPP promoted EP matrix decomposed ahead of time compared with that of pure EP and led to a higher char yield at high temperature. The incorporation of BDMPP enhanced the mechanical properties and reduced the moisture absorption of EP thermosets. The morphological structures of char residue revealed that BDMPP benefited to the formation of a more compact and homogeneous char layer on the materials surface during burning, which prevented the heat transmission and diffusion, limit the production of combustible gases and then lead to the reduction of the heat release rate. After water resistance tests, EP/BDMPP thermosets still remained excellent flame retardancy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42765.     

纳米Al_2O_3对含磷环氧树脂体系的性能影响

研究了以纳米Al_2O_3作为协同阻燃剂,对EP/DOPO和EP/HPCTP树脂固化物阻燃性能的影响。通过热重分析测试(TGA)、动态热机械分析测试(DMA)、氧指数测定(LOI)及垂直燃烧测试(UL-94)重点探讨了树脂固化物的耐热及阻燃性能。测试结果表明,含磷阻燃剂有助于提高环氧树脂固化物的阻燃性能,但会降低其玻璃化转变温度(Tg)。随着纳米Al_2O_3的加入,残炭率(800℃)、极限氧指数(LOI)得到进一步的提高,并且能够在一定程度上提升树脂固化物的玻璃化转变温度(Tg)和初始热裂解温度(T5%)。     

Effect of a novel phosphorus‐containing compound on the flame retardancy and thermal degradation of intumescent flame retardant polypropylene

A novel flame retardant, tetra(5,5‐dimethyl‐1,3‐ dioxaphosphorinanyl‐2‐oxy) neopentane (DOPNP), was synthesized successfully, and its structure was characterized by FT‐IR, ¹H NMR, and ³¹P NMR. The thermogravimetric analysis (TGA) results demonstrate that DOPNP showed a good char‐forming ability. Its initial decomposition temperature was 236.4°C based on 1% mass loss, and its char residue was 41.2 wt % at 600°C, and 22.9 wt % at 800°C, respectively. The flame retardancy and thermal degradation behavior of novel intumescent flame‐retardant polypropylene (IFR‐PP) composites containing DOPNP were investigated using limiting oxygen index (LOI), UL‐94 test, TGA, cone calorimeter (CONE) test, and scanning electron microscopy (SEM). The results demonstrate that DOPNP effectively raised LOI value of IFR‐PP. When the loading of IFR was 30 wt %, LOI of IFR‐PP reached 31.3%, and it passed UL‐94 V‐0. TGA results show that DOPNP made the thermal decomposition of IFR‐PP take place in advance; reduced the thermal decomposition rate and raised the residual char amount. CONE results show that DOPNP could effectively decrease the heat release rate peak of IFR‐PP. A continuous and compact char layer observed from the SEM further proved the flame retardance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.