Reactive,intumescent, halogen‐free flame retardant for polypropylene

A reactive, intumescent, halogen‐free flame retardant, 2‐({9‐[(4,6‐diamino‐1,3,5‐triazin‐2‐yl)amino]‐3,9‐dioxido‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5]undecan‐3‐yl}oxy)ethyl methacrylate (EADP), was synthesized through a simple three‐step reaction from phosphorus oxychloride, pentaerythritol, hydroxyethyl methacrylate, and melamine. EADP exhibited excellent thermal stability and char‐forming ability, as revealed by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The TGA results show that the temperature at 5% weight loss was 297.8°C and the char yield at 700°C was 51.75%. SEM observation revealed that the char showed a continuous and compact surface and a cellular inner structure with different sizes. Composite of polypropylene (PP) with a 25 wt % addition of EADP (PP/EADP25) passed the UL‐94 V‐0 rating and showed a limiting oxygen index value of 31.5. Compared with those of neat PP, the flexural strength and modulus values of PP/EADP25 were somewhat improved, the tensile strength was basically unchanged, and the notched Izod impact strength was slightly decreased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40054.     

Preparation of a chitosan‐based flame‐retardant synergist and its application in flame‐retardant polypropylene

A novel flame‐retardant synergist, chitosan/urea compound based phosphonic acid melamine salt (HUMCS), was synthesized and characterized by Fourier transform infrared spectroscopy and ³¹P‐NMR. Subsequently, HUMCS was added to a fire‐retardant polypropylene (PP) compound containing an intumescent flame‐retardant (IFR) system to improve its flame‐retardant properties. The PP/IFR/HUMCS composites were characterized by limiting oxygen index (LOI) tests, vertical burning tests (UL‐94 tests), microscale combustion calorimetry tests, and thermogravimetric analysis to study the combustion behavior and thermal stability. The addition of 3 wt % HUMCS increased the LOI from 31.4 to 33.0. The addition of HUMCS at a low additive amount reduced the peak heat‐release rate, total heat release, and heat‐release capacity obviously. Furthermore, scanning electron micrographs of char residues revealed that HUMCS could prevent the IFR–PP composites from forming a dense and compact multicell char, which could effectively protect the substrate material from combusting. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40845.     

Halogen Free flame retardant rigid polyurethane foam with a novel phosphorus−nitrogen intumescent flame retardant

A novel phosphorous‐nitrogen containing intumescent flame retardant, toluidine spirocyclic pentaerythritol bisphosphonate (TSPB), was synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR). Flame retardant rigid polyurethane foams (TSPB‐RPUF) were prepared by using TSPB. The flame retardancy of TSPB on rigid polyurethane foams (RPUF) was investigated by the limiting oxygen index (LOI), vertical burning test, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and FTIR. The results showed TSPB exhibited better compatibility with RPUF and lesser negative influence on the mechanical properties of TSPB‐RPUF. When the content of TSPB was 30 pph, the LOI of TSPB‐RPUF could reach 26.5%, and a UL‐94 V‐0 rating was achieved. Furthermore, the TSPB‐RPUF exhibited an outstanding water resistance that it could still obtain a V‐0 rating after water soaking. TGA showed the charring ability of RPUF was relatively poor, However, the residual weight of TSPB‐RPUF was improved greatly. SEM and FTIR indicated the intumescent chars formed from TSPB‐RPUF were compact and smooth, which was a critical factor for protecting the substrate material from burning. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39581.     

Thermal degradation behaviors of polypropylene with novel silicon‐containing intumescent flame retardant

The N‐[3‐(dimethoxy‐methyl‐silanyl)‐propyl]‐N′‐ (9‐methyl‐3,9‐dioxo‐2,4,8,10‐tetraoxa‐3,9‐diphospha‐spiro[5.5]undec‐3‐yl)‐ethane‐1,2‐diamine/dimethoxy dimethyl silane copolymer (PSiN II), which simultaneously contains silicon, phosphorus, and nitrogen, is synthesized and incorporated into polypropylene (PP). The flame retardancy is evaluated by the limiting oxygen index value, which is enhanced to 29.5 from 17.4 with 20% total loading of PSiN II. The thermal degradation behavior of PP/PSiN II is investigated by thermogravimetric analysis under N₂ and air. The PP/PSiN II sample degrades at 400°C for different amounts of time, and the process of degradation is studied by Fourier transform IR. The morphology of the char formed at 400°C for 10 min is investigated by scanning electron microscopy. The swollen inner structure, close, and smooth outer surface provide a much better barrier for the transfer of heat and mass during fire and good flame retardancy. The thermal stability of PP is improved by incorporation of PSiN II. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2487–2492, 2005     

Synergistic flame‐retardant effect of halloysite nanotubes on intumescent flame retardant in LDPE

Synergistic flame‐retardant effect of halloysite nanotubes (HNTs) on an intumescent flame retardant (IFR) in low‐density polyethylene (LDPE) was investigated by limited oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis (TGA), cone calorimeter (CC) test, and scanning electronic microscopy (SEM). The results of LOI and UL‐94 tests indicated that the addition of HNTs could dramatically increase the LOI value of LDPE/IFR in the case that the mass ratio of HNTs to IFR was 2/28 at 30 wt % of total flame retardant. Moreover, in this case the prepared samples could pass the V‐0 rating in UL‐94 tests. CC tests results showed that, for LDPE/IFR, both the heat release rate and the total heat release significantly decreased because of the incorporation of 2 wt % of HNTs. SEM observations directly approved that HNTs could promote the formation of more continuous and compact intumescent char layer in LDPE/IFR. TGA results demonstrated that the residue of LDPE/IFR containing 2 wt % of HNTs was obviously more than that of LDPE/IFR at the same total flame retardant of 30 wt % at 700°C under an air atmosphere, and its maximum decomposing rate was also lower than that of LDPE/IFR, suggesting that HNTs facilitated the charring of LDPE/IFR and its thermal stability at high temperature in this case. Both TGA and SEM results interpreted the mechanism on the synergistic effect of HNTs on IFR in LDPE, which is that the migration of HNTs to the surface during the combustion process led to the formation of a more compact barrier, resulting in the promotion of flame retardancy of LDPE/IFR. In addition, the mechanical properties of LDPE/IFR/HNTs systems were studied, the results showed that the addition of 0.5–2 wt % of HNTs could increase the tensile strength and the elongation at break of LDPE/IFR simultaneously. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40065.     

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.     

Synergistic effect of metal oxides on the flame retardancy and thermal degradation of novel intumescent flame‐retardant thermoplastic polyurethanes

The synergistic effects of some metal oxides on novel intumescent flame retardant (IFR)–thermoplastic polyurethane (TPU) composites were evaluated by limiting oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis (TGA), cone calorimetry, and scanning electron microscopy. The experimental data indicated that the metal oxides enhanced the LOI value and restricted the dropping of the composites. The IFR–TPU composites passed the UL‐94 V‐0 rating test (1.6 mm) in the presence of magnesium oxide (MgO) and ferric oxide (Fe₂O₃) at 35 wt % IFR loading, whereas only the MgO‐containing IFR–TPU composite reached a UL‐94 V‐0 rating at 30 wt % IFR loading. The TGA results show that the metal oxides had different effects on the process of thermal degradation of the IFR–TPU compositions. MgO easily reacted with polyphosphoric acid generated by the decomposition of ammonium polyphosphate (APP) to produce magnesium phosphate. MgO and Fe₂O₃ showed low flammability and smoke emission due to peak heat release rate, peak smoke production rate, total heat release, and total smoke production (TSP). However, zinc oxide brought an increase in the smoke production rate and TSP values. Among the metal oxides, MgO provided an impressive promotion on the LOI value. The alkaline metal oxide MgO more easily reacted with APP in IFRs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis,thermal degradation,and flame retardance of novel triazine ring‐containing macromolecules for intumescent flame retardant polypropylene

Two novel triazine ring‐containing macromolecules, designated as charring‐foaming agent 1 (CFA1) and charring‐foaming agent 2 (CFA2), were synthesized by a series of polycondensation reactions. Their chemical structures were analyzed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (¹³C solid‐state NMR), and elemental analysis, and their thermal degradation properties were assessed by thermogravimetric analysis (TGA). TGA data revealed that CFA1 and CFA2 show high thermal stability and have a high propensity for char formation, their initial decomposition temperatures being 300.2°C and 287.1°C, and their char residues at 800°C amounting to 32.2 wt % and 21.1 wt %, respectively. CFA1 presents higher thermal stability and more char residue than CFA2. Based on experimental results of the flame retardancy (limiting oxygen indices values and UL‐94 V‐0 rating) and the TG data of new intumescent flame retardant polypropylene (IFR‐PP) containing CFA1 and CFA2, CFA1 exhibits more outstanding intumescent flame retardance than CFA2. IFRs containing CFA1 and CFA2 enhanced Notched Izod Impact strength of IFR‐PP, and slightly lower tensile strength of IFR‐PP. IFR2 shows more advantageous effect on mechanical properties of IFR‐PP than IFR1. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of phosphorus‐containing flame‐retardant antistatic copolymers and their applications in polypropylene

By adjusting the molar ratios of antistatic monomer of octyl phenol ethylene oxide acrylate (denoted as AS), rigid monomer of methyl methacrylate (denoted as MMA), and flame‐retardant monomer of 2‐(phosphoryloxymethyl oxyethylene) acrylate (denoted as FR), a series of flame‐retardant antistatic copolymers poly (octyl phenol ethylene oxide acrylate‐co‐methyl methacrylate‐co‐phosphoryloxymethyl oxyethylene acrylate) (donated as AMF) were synthesized through radical polymerization. Among the obtained copolymers, two copolymers, AMF162 (the feed molar ratio of AS, MMA, and FR as 1 : 6 : 2) and AMF1104 (the feed molar ratio of AS, MMA, and FR as 1 : 10 : 4) with different concentrations were added into polypropylene (PP) to prepare PP‐AMF162 and PP‐AMF1104 series of composites. The thermal stability, limiting oxygen index, the antistatic property, and mechanical properties of PP composites were tested and analyzed. PP‐AMF162 series composites have excellent antistatic effect. When the AMF162 content was equal to or <15 wt %, the impact strength of PP‐AMF162 composites was higher than that of pure PP. The results indicated that copolymer AMF162 was a suitable flame‐retardant and antistatic additive for PP. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41677.     

Effect of expandable graphite on the properties of intumescent flame‐retardant polyurethane foam

Water‐blown rigid polyurethane foam (PUF) with two different particle sizes (180 and 300 μm) of expandable graphite (EG) as a flame‐retardant additive were prepared, and the effects on the mechanical, morphological, water absorption, thermal conductivity, thermal, and flame‐retardant properties were studied. In this investigation, EG content was varied from 5 to 50 php by weight. The mechanical properties of PUF decreased with increasing EG loading in both cases. The water absorption of the PUF increased with an increase in the EG loading mainly because of the collapse of foam cells, as evidenced from the scanning electron microscopy pictures. The thermal conductivity of the EG‐filled PUF showed that the insulation properties decreased with EG loading. The flame‐retardant properties (limiting oxygen index and char yield measurement) of the PUF improved with increasing EG loading. PUF filled with the higher particle size EG showed better mechanical properties and fire‐retardant properties than the PUF filled with the lower particle size EG. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Halogen‐free flame‐retardant waterborne polyurethane with a novel cyclic structure of phosphorus−nitrogen synergistic flame retardant

A novel phosphorus?nitrogen flame retardant, octahydro‐2,7‐di(N,N‐dimethylamino)‐1,6,3,8,2,7‐dioxadiazadiphosphecine (ODDP), with bi‐phosphonyl in a cyclic compound, was synthesized by the reaction of POCl₃, NH(CH₃)₂·HCl with OHCH₂CH₂NH₂ in CH₂Cl₂ solution, and characterized by Fourier transform infrared spectrometer, nuclear magnetic resonance, and mass spectrum. ODDP has been successfully reacted with polyurethane (PU) as a chain extender to prepare phosphorus–nitrogen synergistic halogen‐free flame‐retardant waterborne PU (DPWPU). Limiting oxygen index (LOI), UL‐94, thermogravimetric analysis and scanning electron microscopy suggest the excellent flame retardancy of the DPWPU polymer. When the content of ODDP was 15 wt %, the LOI of DPWPU was 30.6% and UL‐94 achieved a V‐0 classification. Compared with the unmodified WPU, the thermodecomposition temperature of the DPWPU was reduced and the amount of carbon residue was increased to 18.18%. The surface of carbon residue was shown to be compact and smooth without holes, which would be favorable for resisting oxygen and heat. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41288.     

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     

Crystallization,melting behavior,and crystal structure of reactive,intumescent, flame‐retardant polypropylene

Polypropylene (PP)/2‐({9‐[(4,6‐diamino‐1,3,5‐triazin‐2‐yl) amino]‐3,9‐dioxido‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro [5.5] undecan‐3‐yl} oxy) ethyl methacrylate (EADP) composites were prepared by the blending of PP with EADP as a new flame‐retardant material. The nonisothermal crystallization and melting behaviors of composites were investigated with differential scanning calorimetry (DSC). Their crystal morphologies and structures were studied by polarized optical microscopy (POM) and X‐ray diffraction (XRD), respectively. The DSC results show that the addition of EADP increased the crystallization onset temperature, crystallization peak temperature, and degree of crystallinity of PP in the PP/EADP composites. The melting onset temperature and melting end temperature of the PP/EADP composites decreased slightly, whereas the melting peak temperature of the PP/EADP composites increased. The POM results show that the addition of EADP greatly reduced the crystal size of PP in the composites. When the content of EADP in the PP/EADP composites was increased, the crystal size of PP became smaller. The XRD results indicate that the addition of EADP changed the crystal structure of PP in the PP/EADP composites, which exhibited both α‐form and β‐form crystal structures. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41374.     

Synergistic flame retardant effect of piperazine salt and ammonium polyphosphate as intumescent flame retardant system for polypropylene

Amino trimethylene phosphonic acid piperazine (ATPIP) salt, as a novel charring agent, is prepared via a simple ionic reaction in distilled water using amino trimethylene phosphate (ATMP) and piperazine as raw materials. The synergistic flame retardant effect of ATPIP and ammonium polyphosphate (APP) as an intumescent flame retardant (IFR) is investigated by various characterization and testing methods. The results show that the polypropylene (PP)/modified APP with piperazine (MAPP)/ATPIP ternary blend passes UL-94 V-0 rating and achieve a limiting oxygen index (LOI) of 30% at a loading level of 25 wt% IFR (MAPP:ATPIP = 3:1). Meanwhile, the total smoke production (TSP) value of IFR-PP samples is 3.3 m², which decreases by 93.2% compared with that of pure PP, exhibiting excellent smoke suppression performance. Besides, the analysis of gaseous pyrolysis products and char residue indicates that the IFR-PP samples show a synergistic flame-retardant mechanism including the gas phase and the condensed phase.     

Novel phosphorus‐based flame retardants containing 4‐tert‐butylcalix[4]arene: Preparation and application for the fire safety of epoxy resins

A novel flame retardant (FR) containing phosphorus and 4‐tert‐butylcalix[4]arene was synthesized and characterized. The FR combined with ammonium polyphosphate (APP) was then incorporated into epoxy resins (EPs) at different ratios. The flame retardancy, thermal stability, and smoke‐releasing properties were investigated. The limiting oxygen index was as high as 30.8% when the mass fraction ratio of the FR to APP was 1:2. The improved FR effect have been due to the combined FR effects between the FR and APP. The char residue content at 800 °C under a nitrogen atmosphere increased notably from 8.22% to 17.6% when the FR APP was incorporated into EP; this indicated an improvement in the thermooxidation resistance. From the cone test, we found that both the total heat‐release and peak heat‐release rate of the FR resins were reduced. Compared to the resins containing no FRs, the smoke‐production rate and total smoke‐production results indicate that the FR resins also exhibited good smoke‐suppression properties. Generally, the stable char layer of the FR APP–EP not only effectively prevented the release of combustion gases but also hindered the propagation of oxygen and heat into the interior substrate. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45105.     

Microencapsulation of intumescent flame‐retardant agent: Application to flame‐retardant natural rubber composite

The first part of this investigation focused on the synthesis and characterization of a microencapsulated intumescent flame retardant (MIFR) agent. Two steps were used in the synthesis process. The structure was characterized by scanning electron microscopy, thermogravimetric anaylysis, and Fourier transform infrared spectroscopy. The addition of this MIFR agent into natural rubber (NR) led to an improvement in its physicomechanical and flame‐retardant (FR) properties. The second part focused on the evaluation of such characteristics as cure characteristics, FR property, tensile properties, abrasion resistance, and dynamic mechanical analysis of MIFR filled NR composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1828–1838, 2007     

Aging of the flame‐retardant properties of polycarbonate and polypropylene protected by an intumescent coating

Flame retardancy (FR) in polycarbonate (PC) and polypropylene (PP) was obtained through the application of an intumescent coating on the polymeric substrate. A better performance was obtained with PC, a char former and highly viscous polymer, compared to with PP. Indeed, whereas 61 μm was required to obtain good FR (by the UL94 V0 rating, in particular) in the case of PC, at least 158 μm needed to be used to give FR to PP. The aging of the coated materials induced by UV‐filtered light radiation was then studied. This exposure led to a decrease in the FR. This effect was more pronounced in the case of PP compared to that of PC. The decrease in the FR was attributed to a decrease in the adhesion of the coating on the polymeric substrate because of its suspected physical aging. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39566.     

Highly flame‐retardant bio‐based polyurethanes using novel reactive polyols

Poor flame retardancy of polyurethanes (PU) is a global issue as it limits their applications particularly in construction, automobile, and household appliances industries. The global challenge of high flammability of PU can be addressed by incorporating flame‐retardant materials. However, additive flame‐retardants are non‐compatible and depreciate the properties of PU. Hence, reactive flame‐retardants (RFR) based on aliphatic (Ali‐1 and Ali‐2) and aromatic (Ar‐1 and Ar‐2) structured bromine compounds were synthesized and used to prepare bio‐based PU using limonene dimercaptan. The aromatic bromine containing foams showed higher close cell content (average 97 and 100%) and compressive strength (230 and 325 kPa) to that of aliphatic bromine containing foams. Similar behavior was observed for a horizontal burning test where with a low concentration of bromine (5 wt %) in the foams for Ar‐1 and Ar‐2 displayed a burning time of 12.5 and 11.8 s while, Ali‐1 and Ali‐2 displayed burning time of 25.7 and 37 s, respectively. Neat foam showed a burning time of 74 s. The percentage weight loss for neat PU foam was 26.5%, while foams containing 5 wt % bromine in Ali‐1, Ali‐2, Ar‐1, and Ar‐2 foams displayed weight loss of 11.3, 14, 7.9, and 14%, respectively. Our results suggest that flame retardant PU foams could be prepared effectively by using RFR materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46027.     

Halogen‐free intumescent flame‐retardant ethylene‐vinyl acetate copolymer system based on organic montmorillonite and graphene nanosheets

Halogen‐containing flame retardants are not preferred for environmental reasons. Herein, a halogen‐free intumescent flame‐retardant ethylene‐vinyl acetate copolymer (EVA/IFR) system containing organic montmorillonite (OMMT) and graphene nanosheets (GNSs) is fabricated with well dispersion structure, enhanced thermal‐oxidative resistance at high temperature. Interestingly, the amount of residual chars from thermogravimetric analysis is increased to 12.7 wt % at 700 °C, the EVA/IFR composite containing both OMMT and GNSs exhibits the best flame retardancy with the lowest peak heat release rate value of 529.58 kW m^?2, and the highest limited oxygen index value of 24.8%. The excellent flame retardancy is attributed to the formation of complete and compact protective char layer. Furthermore, the decreases of the mechanical properties caused by the addition of IFR are relieved and a high volume resistivity is maintained when combining OMMT and GNSs in the EVA/IFR system together. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46361.     

Study on flame‐retardancy and thermal degradation behaviors of intumescent flame‐retardant polylactide systems

Two intumescent flame‐retardant (IFR) additives, IFR‐I and IFR‐II, were synthesized and their structure was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Polylactide (PLA) was modified by the two IFRs to obtain flame‐retardant composites. The flammability of the PLA/IFR composites was characterized by the vertical burning test UL‐94 and limiting oxygen index. The limiting oxygen index values of the PLA composites increased with increase of IFR content. The PLA composite with 20 wt% IFR‐I could pass the UL‐94 V0 rating, while the composite with 30 wt% IFR‐II could not. The results of pyrolysis combustion flow calorimetry showed that the heat release capacity of PLA composites with 30 wt% IFR‐I decreased 43.1% compared with that of pure PLA. The thermal degradation and gas products of PLA/IFR‐I systems were monitored by thermogravimetric analysis and thermogravimetric analysis infrared spectrometry. Scanning electron microscopy was used to investigate the surface morphology of the char residue. Copyright © 2011 Society of Chemical Industry