Synergistic effect between a novel hyperbranched charring agent and ammonium polyphosphate on the flame retardant and anti-dripping properties of polylactide

A novel hyperbranched polyamine charring agent (HPCA), a derivative of triazines, was synthesized and well characterized by ¹H NMR and FTIR. HPCA and ammonium polyphosphate (APP) were added into polylactide (PLA) resin as an intumescent flame retardant (IFR) system to impart flame retardancy and dripping resistance to PLA. The flammability and thermal stability of IFR-PLA composites were investigated by limiting oxygen index (LOI), UL-94 vertical burning, cone calorimetry and thermogravometric analysis (TGA) tests. The results showed that the IFR system had both excellent flame retardant and anti-dripping abilities for PLA. The TGA curves suggested that HPCA has good ability of char formation and when combined with APP, would induce synergistic effect which could be clearly observed. This effect greatly promoted the char formation of IFR-PLA composites, hence improved the flame retardant property. Additionally, the structure and morphology of char residues were studied by XPS, FTIR and SEM.     

Inherent flame retardation of bio-based poly(lactic acid) by incorporating phosphorus linked pendent group into the backbone

The molecular design for inherently flame-retardant poly(lactic acid) (IFR-PLA) was outlined and achieved by chemically incorporating an effective organophophorus-type flame retardant (FR) into the PLA backbone via the chain extension of the dihydroxyl-terminated prepolymer with 1, 6-hexamethylene diisocyanate (HDI). The structure of IFR-PLA was characterized by ¹H- and ³¹P-nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. IFR-PLA was further blended with the commercial PLA to prepare flame retardant PLA blends (PLA-FR blend). The relevant properties of IFR-PLA and PLA-FR blends were evaluated by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), limiting oxygen index (LOI) measurements and UL-94 tests. The thermal analysis revealed that the char yield of IFR-PLA and PLA-FR blend above 400 °C was greatly enhanced compared to that of pure PLA. The LOI value was significantly improved from 19 for pure PLA to 29 when 1 wt% of phosphorus content was introduced and all IFR-PLA samples achieved V-0 rating in the UL-94 tests. PLA-FR blends had an LOI value of 25-26 and UL-94 V-2 rating at 20 wt% of IFR-PLA content. The tensile strength of all the FR PLA systems was ca. 60 MPa. The method used in this study provided a novel route to permanently flame retard PLA.     

Synthesis of functionalized α-zirconium phosphate modified with intumescent flame retardant and its application in poly(lactic acid)

A novel functionalized α-zirconium phosphate (F-ZrP) modified with intumescent flame retardant was synthesized by co-precipitation method and characterized. Poly (lactic acid) (PLA)/F-ZrP nanocomposites were prepared by melt blending method. The thermal stability and combustion behavior of PLA/F-ZrP nanocomposites were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical burning test (UL-94), scanning electronic microscopy (SEM), and cone calorimeter test (CCT). The results showed that the addition of flame retardant F-ZrP slightly affect PLA's thermal stability, but significantly improve the flame retardancy of PLA composites. In comparison with neat PLA, the LOI value of PLA/F-ZrP was increased from 19.0 to 26.5, and the UL-94 rating was enhanced to V-0 as the loading of F-ZrP at 10%. SEM results suggested the introduction of F-ZrP in the PLA system can form compact intumescent char layer during burning. All these results showed that the F-ZrP performed good flame retardancy for PLA.     

Synthesis of a novel polyphosphazene/triazine bi‐group flame retardant in situ doping nano zinc oxide and its application in poly (lactic acid) resin

A novel polyphosphazene/triazine bi‐group flame retardant in situ doping nano ZnO (A4‐d‐ZnO) was synthesized and applied in poly (lactic acid) (PLA). Fourier transform infrared (FTIR), solid state nuclear magnetic resonance (SSNMR), X‐ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM), and energy dispersive spectrometer (EDS) were used to confirm the chemical structure of A4‐d‐ZnO. The thermal stability and the flame‐retardant properties of the PLA composites were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), limiting oxygen index (LOI), vertical burning test (UL‐94), and micro combustion calorimeter (MCC) test. The results of XPS showed that A4‐d‐ZnO has been synthesized, and the doping ratio of ZnO was 7.2% in flame‐retardant A4‐d‐ZnO. TGA results revealed that A4‐d‐ZnO had good char forming ability (40 wt% at 600°C). The results of LOI, vertical burning test, and MCC showed that PLA/5%A4‐d‐ZnO composite acquired a higher LOI value (24%), higher UL94 rating, and lower pk‐HRR (501 kW/m²) comparing with that of pure PLA. It indicated that a small amount of flame‐retardant A4‐d‐ZnO could achieve great flame‐retardant performance in PLA composites. The catalytic chain scission effect of A4‐d‐ZnO could make PLA composites drip with flame and go out during combustion, which was the reason for the good flame‐retardant property. Moreover, after the addition of A4‐d‐ZnO, the impaired mechanical properties of PLA composites are minimal enough.     

A novel phosphazene cyclomatrix network polymer: Design, synthesis and application in flame retardant polylactide

A novel phosphazene cyclomatrix network polymer poly(cyclotriphosphazene-co- pentaerythritol) (PCPP) was synthesized and characterized based on an attempt to look for a high efficient and green intumescent flame retardant. A series of flame retardant polylactide (FR-PLA) composites containing PCPP were prepared by melt blending method. Thermal degradation behavior and combustion properties of FR-PLA composites were evaluated through thermogravimetric analysis, UL-94 experiments, limiting oxygen index and cone calorimeter tests. It is found that the weight of residues for FR-PLA composites improved greatly with the addition of PCPP. Additionally, PCPP show a high flame retardant efficiency for PLA, UL-94 V-0 could be passed only containing 5 wt% PCPP. Fourier transform infrared spectra and scanning electronic microscopy investigations reveal that the residual chars are compact and foaming containing P-O-C structure, which restrains the development of fire and increases the flame retardant properties.     

An efficient halogen-free flame retardant for glass-fibre-reinforced poly(butylene terephthalate)

Compared with poly(butylene terephthalate) (PBT), glass-fibre-reinforced poly(butylene terephthalate) (GF-PBT) is difficult to flame retard with halogen-free flame retardants. In the present study, the aluminium salt of hypophosphorous acid (AP) was used as a flame retardant for GF-PBT. A series of flame-retardant GF-PBT composites was prepared via melt compounding. The flame retardance and combustion behaviour of the composites were studied by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimetric test. Thermal behaviours and thermal decomposition kinetics were investigated by thermogravimetric analysis (TGA) under N₂ atmosphere. The addition of AP to the composites could result in an increased LOI value, a UL-94 V-0 (1.6 mm) classification and a better fire performance in cone calorimetric tests. The char morphology observation after flame-retardant tests, calculation of decomposition kinetics, X-ray photoelectron spectroscopy (XPS) and infra-red spectral analysis of the char residue confirmed the condensed-phase flame-retardant mechanism. Furthermore, the mechanical properties of the flame-retardant composites were not deteriorated, retaining an acceptable level.     

Effect of aluminum diethylphosphinate on flame retardant and thermal properties of rigid polyurethane foam composites

Rigid polyurethane foam/aluminum diethylphosphinate (RUPF/ADP) composites were prepared by one-step water-blown method. Furthermore, scanning electron microscope (SEM), thermal conductivity meter, thermogravimetric analysis (TGA), limiting oxygen index, Underwriters Laboratories vertical burning test (UL-94) and microsacle combustion calorimetry were applied to investigate thermal conductivity, thermal stability, flame retardancy and combustion behavior of RPUF/ADP composites. Thermogravimetric analysis–Fourier transform infrared spectroscopy (TG–FTIR) was introduced to investigate gaseous products in degradation process of RPUF/ADP composites, while SEM and X-ray photoelectron spectroscopy were used to research char residue of the composites. It was confirmed that RPUF/ADP composites presented well cell structure with density of 53.1–59.0 kg m^?3 and thermal conductivity of 0.0425–0.0468 W m^?1 K^?1, indicating excellent insulation performance of the composites. Flame retardant test showed that ADP significantly enhanced flame retardancy of RPUF/ADP composites, RPUF/ADP30 passed UL-94 V-1 rating with LOI of 23.0 vol%. MCC test showed that ADP could significantly decrease peak of heat release rate (PHPR) of RPUF/ADP composites. PHPR value of RPUF/ADP20 was decreased to 158 W g^?1, which was 21.8% reduced compared with that of pure RPUF. TG–FTIR test revealed that the addition of ADP promoted the release of CO₂, hydrocarbons and isocyanate compound in first-step degradation of RPUF matrix while inhibited the release of CO in second step degradation. Char residue analysis showed that the addition of ADP promoted polyurethane molecular chain to form aromatic and aromatic heterocyclic structure, enhancing strength and compactness of the char. This work associated a gas–solid flame retardancy mechanism with the incorporation of ADP, which presented an effective strategy for preparation of flame retardant RPUF composites.

     

Synthesis of a silicon-containing flame retardant and its synergistic effect with potassium-4-(phenylsulfonyl)benzenesulfonate (KSS) in polycarbonate (PC)

A novel flame retardant (DAPSiO), containing silicon and nitrogen, was synthesized by using dichlorodiphenylsilane, γ-chloropropyl methyl dimethoxysilane and 1,2-ethanediamine. DAPSiO was used together with potassium-4-(phenylsulfonyl)benzenesulfonate (KSS) to prepare a flame-retardant system for polycarbonate (PC). The structure of DAPSiO was characterized by Fourier transform infrared spectroscopy (FTIR), and ¹H-NMR tests. Flammability and thermal behaviors of PC/KSS/DAPSiO systems were estimated by limited oxygen index (LOI), vertical burning test (UL-94) and thermogravimetric analysis (TGA) tests. The results showed that the flame retardancy and thermal stability of PC/KSS system were improved with the addition of DAPSiO. When 1 wt% DAPSiO and 0.5 wt% KSS were incorporated, the LOI value of PC was found to be 44, and class V-0 of UL-94 test was passed. The scanning electron microscopy (SEM) and FTIR indicated that PC/KSS/DAPSiO system held a more cohesive and denser char structure when compared with pure PC and PC/KSS system.     

Simultaneous improvement in the flame retardancy and water resistance of PP/APP through coating UV-curable pentaerythritol triacrylate onto APP

To improve the flame-retardant efficiency and water resistance of ammonium polyphosphate(APP), the UV-curable pentaerythritol triacrylate(PETA) was used to microencapsulate APP via the UV curing polymerization method. The prepared PETA-microencapsulated APP(PETA-APP) was characterized by Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), and thermogravimetric(TG) analysis. PETA-APP was used as intumescent flame retardant(IFR) alone to flame retard polypropylene(PP). The water resistance of PP/PETA-APP composites was investigated, and the effect of PETA on the combustion behaviors of PP/APP composites was studied through limiting oxygen index(LOI), vertical burning test(UL-94) and cone calorimeter(CC) test, respectively. With 40 wt% of PETA-APP, the PP/PETA-APP system could achieve a LOI value of 30.0% and UL-94 V-0 rating after treatment in hot water for 168 h, while the LOI value of the system containing 40 wt% uncoated APP was only 19.2%, and it failed to pass the UL-94 rating. CC test results showed that the heat release rate(HRR), mass loss rate(MLR) and smoke production rate(SPR) of PP/PETAAPP system decreased significantly compared with PP/APP system, especially the peak of HRR was decreased by 51.4%. The mechanism for the improvement of flame reatardancy for PP/PETA-APP composites was discussed based on FTIR and X-ray photoelectron spectroscopy(XPS) tests. All these results illustrated that simultaneous improvement of flame retardancy and water resistance for PP/APP was achieved through coating UV-curable PETA onto APP.     

磷化淀粉的合成及其与聚磷酸铵协效阻燃聚乳酸的性能研究

利用9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)和马来酸酐(MA)对淀粉进行改性得到磷化淀粉(DOPOMASt),通过红外光谱(FTIR)、核磁共振谱(1H-NMR)和X射线光电子能谱(XPS)确定其结构.利用DOPOMASt作为碳源,与聚磷酸铵(APP)复配后通过熔融共混制备了阻燃聚乳酸(PLA)...     

Flame retardant properties and mechanism of an efficient intumescent flame retardant PLA composites

The charring agent (CNCA‐DA) containing triazine and benzene rings was combined with ammonium polyphosphate (APP) to form intumescent flame retardant (IFR), and it was occupied to modify polylactide (PLA). The flame retardant properties and mechanism of flame retardant PLA composites were investigated by the limited oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis, microscale combustion calorimetry, scanning electron microscopy, laser Raman spectroscopy analysis and X‐ray photoelectron spectroscopy. The analysis from LOI and UL‐94 presented that the IFR was very effective in flame retardancy of PLA. When the weight ratio of APP to CNCA‐DA was 3:1, and the IFR loading was 30%, the IFR showed the best effect, and the LOI value reached 45.6%. It was found that when 20 wt% IFR was loaded, the flame retardancy of PLA/IFR still passed UL‐94 V‐0 rating, and its LOI value reached 32.8%. The microscale combustion calorimetry results showed that PLA/IFR had lower heat release rate, total heat release, and heat release capacity than other composites, and there was an obvious synergistic effect between APP and CNCA‐DA for PLA. IFR containing APP/CNCA‐DA had good thermal stability and char‐forming ability with the char residue 29.3% at 800°C under N₂ atmosphere. Scanning electron microscopy observation further indicated that IFR could promote forming continuous and compact intumescent char layer. The laser Raman spectroscopy analysis and X‐ray photoelectron spectroscopy analysis results indicated that an appropriate graphitization degree of the residue char was formed, and more O and N were remained to form more cross‐linking structure. Copyright © 2016 John Wiley & Sons, Ltd.     

Flame retardation of glass-fibre-reinforced polyamide 6 by a novel metal salt of alkylphosphinic acid

Aluminum salts of phosphinic acid mixture of diisobutylphosphinic acid and monoisobutylphosphinic acid (HPA-2TBA-Al) and glass fibres were compounded with polyamide 6 to prepare a series of flame retardant GF/PA6 composites via melt blending. The flame retardance and burning behaviors of the composites were investigated by limiting oxygen index (LOI), vertical burning test (UL-94), and Cone calorimeter test. The thermal properties and decomposition kinetics were investigated by thermogravimetric analysis (TGA) under N₂ atmosphere. Addition of HPA-2TBA-Al results in an increased LOI value, a UL-94 V-0 rating together with a decrease in both the values of PHRR and THR in Cone calorimetric analysis. Visual observations and scanning electronic microscopy (SEM) after flame retardant tests confirmed the char-formation which acts as a fire barrier in condense phase. Analysis of cone calorimeter data indicates that gas phase flame retardant mechanism exists in the GFPA6/HPA-2TBA-Al system.     

A novel halogen-free flame retardant for glass-fiber-reinforced poly(ethylene terephthalate)

In order to prepare halogen-free flame-retardant glass-fiber-reinforced poly(ethylene terephthalate) (FR-GF-PET), a novel flame retardant containing three flame-retardant elements, P, N and S, was synthesized by melt condensation reaction. Its chemical structure was characterized by FT-IR and ¹H NMR spectra. FR-GF-PET was prepared by melt-mixing the flame retardant with GF-PET. The effects of the flame retardant on the flammability and thermally decomposing behaviors of GF-PET were studied via LOI, UL-94 and TGA tests. The results showed that despite a negative effect on the thermal stability of GF-PET, the incorporation of the flame retardant improved the flame retardancy of GF-PET largely. The LOI values of GF-PET increase linearly with the increase of flame retardant content. The GF-PET passed the V-0 rating in UL-94 tests when 15 wt% of the flame retardant was added to GF-PET. An interesting phenomenon was found, that is, with the increase of flame retardant content, the flame retardancy of the system increased but the char yield decreased, which was explained according to the evidences of XPS tests and the kinetics of thermally decomposing reaction.     

Experimental study on liquid fire behavior at different effective ceiling heights in a full-size simulated cargo compartment

A phosphorus-containing maleimide flame retardant (BDMP) was synthesized via the addition reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide and N,N′-bismaleimide-4,4′-diphenylmethane. The structure of BDMP was characterized by Fourier-transform infrared spectroscopy (FTIR), ¹H and ³¹P nuclear magnetic resonance and elemental analysis. The thermal, flame-retardant and mechanical properties of the flame-retardant cyanate ester system were investigated by thermogravimetric analysis (TG), limiting oxygen index (LOI), vertical burning (UL-94), cone calorimeter test and dynamic mechanical analysis. The TG results indicated that the initial decomposition of modified CE resin shifted from 416 to 363 °C, and on the contrary, the char yield increased from 38.8 to 44.5%. The results of combustion tests indicated that the CE with highest phosphorus content acquired LOI value of 37% and achieved a UL-94 V-0 rating. The peak heat release rate, average heat release rate and average of effective heat combustion (av-EHC) of that group decreased by 39.5, 31.2 and 41.8%, respectively. In addition, the increase in phosphorus content led to a decrease in av-EHC and average CO₂ yield, and an increase in average CO yield, indicating that BDMP led to an incomplete combustion of the modified CE system. The flame-retardant mechanism was investigated by TG–FTIR, scanning electron microscope and cone calorimeter. Last but not least, the dielectric constant of modified CE system showed a slight fluctuation from 2.96 to 3.02 at 1 GHz, which was lower than that of neat CE.     

Evaluation of activation energy conformity derived from model-free non-isothermal predictions and Arrhenius isothermal results

Organically modified montmorillonite (OMMT) was used as synergist to enhance the flame-retardant and mechanical properties of poly(butylene succinate)/intumescent flame retardant (PBS/IFR) composites. The flame-retardant, thermal degradation and combustion properties of PBS and its flame-retardant composites were characterized by limiting oxygen index (LOI) test, vertical burning (UL-94) test, thermogravimetric analysis, cone calorimeter and scanning electron microscopy, respectively. The results indicate that PBS/IFR composites exhibit excellent flame retardance when OMMT is at an appropriate content. PBS/IFR composite with 20 wt% IFR and 1.5 wt% OMMT has an LOI of 40.1% and can pass the UL-94 V0 rating. The synergistic effect between OMMT and IFR on the flame-retardant properties of PBS depends on the content of OMMT, and excessive OMMT diminish this synergistic effect. The possible flame-retardant mechanism of OMMT on PBS/IFR composite is proposed. The results of mechanical test also indicate that OMMT can effectively increase the notched impact strength of PBS/IFR composites.     

Preparation of a novel phosphorus‐containing organosilicon and its effect on the flame retardant and smoke suppression of polyethylene terephthalate

A novel phosphorus‐containing silicone flame retardant (PDPSI) was prepared by Mannish reaction, and a series of PDPSI/PET composites were prepared by melt blending method. The nuclear magnetic resonance (¹H NMR), Fourier transformation infrared (FTIR), and the thermogravimetric analyzer (TGA) results indicated that PDPSI showed network structure and owned good thermal stability, with the char residue of 62.2% at 800°C. The flame retardancy of PDPSI/PET composites was characterized by limiting oxygen index (LOI), vertical burning tests (UL‐94), and cone calorimeter (CCT). The results revealed that the addition amount of PDPSI was 5%, the LOI value of PDPSI/PET composites increased to 27.3%, and UL‐94 test passed V‐0 rating. When the PDPSI loading was 3%, PET composites showed excellent flame retardancy and smoke suppression, with a decrease in the peak heat release rate (PHRR) by 71.19% and the total smoke release (TSP) reduced from 14.4 to 11.1m². The scanning electron microscopy (SEM) and FTIR results of char residue demonstrated that the flame‐retardant mechanism of PDPSI was solid phase flame retardant. PDPSI catalyzed the aromatization reaction of PET to promote the formation of a dense and continuous carbon layer, finally improving the flame retardancy and smoke suppression properties of PET.     

Flammability characteristics and synergistic effect of hydrotalcite with microencapsulated red phosphorus in halogen-free flame retardant EVA composite

The flammability characteristics and synergistic effect of hydrotalcite with microencapsulated red phosphorus (MRP) in halogen-free flame retardant ethylene vinyl acetate (EVA) composite have been studied by cone calorimeter test (CCT), thermogravimetric analysis (TGA), limiting oxygen index (LOI) and UL-94 test. The results obtained by comparing the flame retardancy of hydrotalcite with magnesium hydroxide (MH) and aluminium hydroxide (AH) for their EVA composites showed that hydrotalcite has higher flame retardant effect than MH and AH at the same loading level. The CCT tests indicated that the heat release rate (HRR) and mass loss rate (MLR) of EVA composite blended with hydrotalcite greatly decreased compared with those blended with MH and AH. The LOI values of EVA/hydrotalcite composites are 3-4% higher than those of the corresponding MH composites at 40-60 wt% loading levels, and 6% higher than that of the corresponding AH composite at 40 wt% loading level. Moreover, the addition of a given amount of MRP apparently resulted in the increase of LOI value and decrease of the HRR and MLR as well the loading of hydrotalcite in EVA blend while keeping the V-0 rating in UL-94 test. However, the smoke release increased during the combustion of EVA/hydrotalcite blend containing MRP.     

Synergistic effect between expandable graphite and ammonium polyphosphate on flame retarded polylactide

Synergistic effect was observed between expandable graphite (EG) and ammonium polyphosphate (APP) on flame retarded polylactide (PLA) in this paper using limiting oxygen index (LOI), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and X-ray spectroscopy (XPS) and cone calorimeter tests etc. In the experiments, PLA composites with 15 wt% of APP/EG(1:3) combinations showed a LOI value of 36.5 and V-0 rating in UL-94 tests, greatly improved flame retardant properties from composites with APP or EG alone. Results from TGA and cone calorimeter demonstrated that APP/EG combination could retard the degradation of polymeric materials above the temperature of 520 °C by promoting the formation of a compact char layer. This char layer protects the matrix effectively from heat penetrating inside and prevents its further degradation, resulting in lower weight loss rate and better flame retarded performance.     

Fire retarded polyurethane foam composites based on steel slag/ammonium polyphosphate system: A novel strategy for utilization of metallurgical solid waste

A series of FR-RPUF composites were prepared by a one-step water foaming process with ammonium polyphosphate (APP) and steel slag (SS) as flame retardants. Thermogravimetric analysis (TG), limiting oxygen index (LOI), UL-94 vertical combustion test, microscale combustion calorimetry (MCC), TG-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscopy (SEM), Raman spectra and FTIR were used to investigate the thermal stability, flame retardancy, combustion performance, gas phase products, and char residue morphology of FR-RPUF composites. TG test results showed that the initial decomposition temperature (T_-5wt%) and char residue rate at 700°C of RPUF/APP/SS composites were significantly enhanced by the addition of APP and SS, and the thermal stability of the composites was improved. Flame retardant test results confirmed the significantly increased LOI values of RPUF/APP/SS composites with V-0 rating. TG-FTIR also confirmed the obviously decreased release of toxic gases and flammable gases in the combustion of RPUF/APP/SS composites. SEM and Raman spectra of char residues for the composites suggested that APP/SS system improved the compactness and graphitization degree of char layer for RPUF/APP/SS composite. The above researches provide a new strategy for the utilization of SS in fire safety engineering.     

Flame retardant mechanism of an efficient flame-retardant polymeric synergist with ammonium polyphosphate for polypropylene

An efficient flame retardant polymeric synergist poly[N⁴-bis(ethylenediamino)-phenyl phosphonic-N², N⁶-bis(ethylenediamino)-1,3,5-triazine-N-phenyl phosphonate] (PTPA) was designed and synthesized from cyanuric chloride, ethylenediamine and phenylphosphonic dichloride. It was characterized by Fourier Transform Infrared (FTIR), ¹H NMR and ³¹P NMR, Elemental Analysis (EA) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Combined with ammonium polyphosphate (APP), a new intumescent flame retardant (IFR) was obtained. The flammability behaviors of polypropylene (PP)/IFR system were investigated by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimetry. With 25 wt% of IFR (APP:PTPA = 2:1), the PP/IFR system could achieve a LOI value of 34.0% and UL-94 V-0 rating, and the heat release rate (HRR), peak heat release rate (PHRR), total heat release (THR) and smoke production rate (SPR) were considerably reduced, especially HRR and SPR were decreased by 85% and 79%, respectively. The results indicate that there is an excellent synergism between APP and PTPA, which endows PP with both good flame retardancy and good smoke suppression. Furthermore, the thermal degradation mechanism of IFR and the flame-retardant mechanism of PP/IFR system were investigated by thermogravimetric analysis (TGA), FT-IR, TG-FTIR and scanning electron microscope (SEM). The study on the flame-retardant mechanism of IFR indicated that a structure containing –CN was formed due to the reaction between APP and PTPA.