Synthesis of aluminum ethylphenylphosphinate flame retardant and its application in epoxy resin

A novel flame retardant additive, aluminum ethylphenylphosphinate (AEPP), was synthesized from diethyl phenylphosphonite and aluminum chloride hexahydrate, and characterized by FTIR, ¹H NMR, and ³¹P NMR. AEPP was added into diglycidyl ether of bisphenol A epoxy resin (EP) cured by bisphenol A‐formaldehyde novolac resin. The flame retardancy of the cured EP was investigated by limited oxygen index, UL 94 test, and cone calorimeter test. The results revealed that the EP composite containing 15% AEPP had a limited oxygen index value of 28.2% with a UL 94 V‐0 rating. The incorporation of AEPP effectively decreased the peak heat release rate and the total heat release in cone calorimeter test analysis. Scanning electron microscopy results showed that the introduction of AEPP benefited to the formation of a smooth and continuous char layer during combustion of the flame retarded EP. The thermogravimetric analysis results indicated that the incorporation of AEPP promoted the initial decomposition of EP matrix, but AEPP/EP composites had a higher char yield at high temperatures. Moreover, the flexural properties of the flame retarded EP composites were studied.     

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.     

A P/N-containing flame retardant constructed by phosphaphenanthrene,phosphonate, and triazole and its flame retardant mechanism in reducing fire hazards of epoxy resin

A P/N-containing flame retardant (PPT) constructed by phosphaphenanthrene, phosphonate, and triazole groups was successfully synthesized and used as a reactive co-curing agent for epoxy resin (EP). The curing behavior, thermal property, combustion behavior, and flame retardant mechanism of EP thermosets were comprehensively investigated. According to the analysis of DSC and TGA, PPT accelerated the crosslinking reaction and enhanced the charring ability for EP thermosets at high temperature. The results of combustion test indicated that PPT endowed epoxy thermoset with outstanding flame retardancy. When the phosphorus content was 0.71 wt%, EP/DDS/PPT-2 achieved a LOI value of 33.2% and passed V-0 rating in UL-94 test, and its peak heat release rate and total heat release were decreased by 63.7 and 30.5%, respectively, relative to EP/DDS. Moreover, the FIGRA of EP/DDS/PPT-2 was reduced from 9.7 to 3.5 kW m⁻² s⁻¹, manifesting the significantly improved fire safety of EP thermoset. The flame retardant mechanism was summarized as two parts: (a) the barrier effect of continuous phosphorus-rich char layers in condensed phase, (b) the quenching effect of phosphorous radicals and diluting effect of nonflammable gases in gaseous phase.     

Ionic liquid modified graphene oxide for enhanced flame retardancy and mechanical properties of epoxy resin

In this work, to improve its dispersion and flame retardancy, graphene oxide (GO) was functionalized by silane coupling agent KH550 and 1-butyl-3-methylimidazole hexafluorophosphate (PF₆-ILs), and characteristics of the PF₆-ILs@GO was obtained by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Then, the synergistic flame retardant of GO or PF₆-ILs@GO and melamine pyrophosphate (MPP) were applied for epoxy resin (EP) materials. Specifically, the limiting oxygen index (LOI) value of EP with 0.1 wt% PF₆-ILs@GO was increased to 29.2% from 27.5% of EP/MPP composites, and the UL-94 test reached the V-0 rating. The CCT results showed that the total heat release (THR) and total smoke release (TSP) of EP/MPP/PF₆-ILs@GO composites were significantly 24.4% and 53.4% lower than that of EP/MPP composites. Besides, the thermal behavior investigated by TGA indicated that the char-forming effect of GO and PF₆-ILs@GO was great, the residual char of EP/MPP/PF₆-ILs@GO composites was as high as 19.5% at 700°C, and its thermal stability was higher than that of EP/MPP composites. On the other hand, the tensile strength of EP/MPP/GO and EP/MPP/PF₆-ILs@GO composites were increased by 15.6% and 28.3% compared with EP/MPP composites. According to SEM analysis, the EP/MPP/GO composites formed a good protective char layer, which can effectively improve flame retardancy of EP. This research represents a new method of flame retardant modified GO to improve the flame retardancy and mechanical properties of polymers.     

Preparation and investigation of flame‐retardant epoxy resin modified with a novel halogen‐free flame retardant containing phosphaphenanthrene,triazine‐trione,and organoboron units

In this article, a novel flame retardant (coded as BNP) was successfully synthesized through the addition reaction between triglycidyl isocyanurate, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide and phenylboronic acid. BNP was blended with diglycidyl ether of bisphenol‐A to prepare flame‐retardant epoxy resin (EP). Thermal properties, flame retardancy, and combustion behavior of the cured EP were studied by thermogravimetric analysis, limited oxygen index (LOI) measurement, UL94 vertical burning test, and cone calorimeter test. The results indicated that the flame retardancy and smoke suppressing properties of EP/BNP thermosets were significantly enhanced. The LOI value of EP/BNP‐3 thermoset was increased to 32.5% and the sample achieved UL94 V‐0 rating. Compared with the neat EP sample, the peak of heat release rate, average of heat release rate, total heat release, and total smoke production of EP/BNP thermosets were decreased by 58.2%–66.9%, 27.1%–37.9%, 25.8%–41.8%, and 21.3%–41.7%, respectively. The char yields of EP/BNP thermosets were increased by 46.8%–88.4%. The BNP decomposed to produce free radicals with quenching effect and enhanced the charring ability of EP matrix. The multifunctional groups of BNP with flame retardant effects in both gaseous and condensed phases were responsible for the excellent flame retardancy of the EP/BNP thermosets. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45291.     

Thermal degradation behaviors and flame retardancy of epoxy resins with novel silicon‐containing flame retardant

A novel macromolecular silicon‐containing intumescent flame retardants (Si‐IFR) was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus‐silicon characterized by IR. Epoxy resins (EP) were modified with Si‐IFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94 and limiting oxygen index (LOI). Twenty percentage of weight of Si‐IFR was doped into EP to get 27.5% of LOI and UL 94 V‐0. The degradation behavior of the flame retardant EP was studied by thermogravimetry, differential thermogravimetry, scanning electron microscopy, and X‐ray photoelectron spectroscopy analysis. The experimental results exhibited that when EP/Si‐IFR was heated, the phosphorus‐containing groups firstly decompose to hydrate the char source‐containing groups to form a continuous and protective carbonaceous char, which changed into heat‐resistant swollen char by gaseous products from the nitrogen‐containing groups. Meanwhile, SiO₂ reacts with phosphate to yield silicophosphate, which stabilizes the swollen char. The barrier properties and thermal stability of the swollen char are most effective in resisting the transport of heat and mass to improve the flame retardancy and thermal stability of EP. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Epoxy resin/phosphorus‐based microcapsules: Their synergistic effect on flame retardation properties of high‐density polyethylene/graphene nanoplatelets composites

Two types of microcapsule flame retardants are prepared by coating ammonium polyphosphate (APP) and aluminum diethylphosphinate (ADP) with epoxy resin (EP) as the shell via in situ polymerization, and blended with high density polyethylene (HDPE)/graphene nanoplatelets (GNPs) composites to obtain flame‐retardant HDPE materials. Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and water contact angle results confirm the formation of core–shell structures of EP@APP and EP@ADP. The limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimetry, and Raman spectroscopy are employed to characterize the HDPE/GNPs composites filled with EP@APP and EP@ADP core–shell materials. A UL94 V‐0 level and LOI of 34% is achieved, and the two flame retardants incorporated in the HDPE/GNPs composite at 20 wt % in total play a synergistic effect in the flame retardancy of the composite at a mass ratio of EP@ADP:EP@APP = 2:1. According to the cone‐calorimetric data, the compounding composites present much lower peak heat release rate (300 kW/m²) and total heat release (99.4 MJ/m²) than those of pure HDPE. Raman spectroscopic analysis of the composites after combustion reveals that the degree of graphitization of the residual char can reach 2.31, indicating the remarkable flame retarding property of the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46662.     

Synthesis of a novel cross‐linked organophosphorus‐nitrogen containing polymer and its application in flame retardant epoxy resins

A novel cross‐linked organophosphorus–nitrogen polymetric flame retardant additive poly(urea tetramethylene phosphonium sulfate) defined as PUTMPS was synthesized by the condensation polymerization between urea and tetrahydroxymethyl phosphonium sulfate. Its chemical structure was well characterized by Fourier transform infrared (FTIR) spectroscopy, ¹³C and ³¹P solid‐state nuclear magnetic resonance. The synthesized PUTMPS and curing agent m‐phenylenediamine were blended into epoxy resins to prepare flame retardant epoxy resin thermosets. The effects of PUTMPS on fire retardancy and thermal degradation behavior of EP/PUTMPS thermosets were investigated by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter measurement, and thermalgravimetric analysis (TGA) tests. The surface morphologies and chemical compositions of char residues for cured epoxy resins were investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy (XPS), respectively. Water resistant properties of epoxy resin thermosets were evaluated by putting the samples into distilled water at 70°C for 168 h. The results demonstrated that the EP/12 wt% PUTMPS thermosets successfully passed UL‐94 V‐0 flammability rating and the LOI value reached 31.3%. The TGA results indicated that the incorporation of PUTMPS promoted epoxy resin matrix decomposed and char forming ahead of time, which led to a higher char yield and thermal stability for epoxy resin thermosets at high temperature. The morphological structures and analysis of XPS for the char residues of the epoxy resin thermosets shown that PUTMPS benefited to the formation of a sufficient, more compact, and homogeneous char layer with rich flame retardant elements on the materials surface during burning, which prevented the heat transmission and diffusion, limited the production of combustible gases, inhibited the emission of smoke, and then led to the reduction of the heat release rate and smoke produce rate. After water resistance tests, EP/12 wt% PUTMPS thermosets still remained excellent flame retardancy. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of gas-condensed phase synergistic system of 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide and polydopamine on flame retardancy of epoxy resin

Polydopamine (PDA) was prepared by using dopamine which has good charring ability. The PDA was used as an environmentally friendly flame retardant and combined with 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide (DOPO) to improve the flame retardancy of epoxy (EP) resin. The flame retardancy and thermal stability of EP composites were researched by UL-94 vertical burning, limiting oxygen index (LOI), cone calorimetry tests, and thermal gravimetric analyzer. Adding DOPO alone requires 6% to make EP obtain the UL-94 V0. If DOPO and PDA are combined, only 4% is needed to make EP obtain the UL-94 V0, which suggests that there is good synergistic effect between them. Moreover, the peak of heat release rate of EP/DOPO/PDA composites is less than that of EP/DOPO composites. The reactions among EP, DOPO, and PDA reduce the release of combustible gases at the early stage of degradation; at the same time, DOPO volatilize to the gas phase, quench the free radicals, and the combustion can be stopped. In addition, due to the decrease of the amount of PDA/DOPO, the EP composite can get a higher glass transition temperature, but due to the aggregation of PDA in EP, the tensile property of EP composite decreases.     

Synergistic effects of dual imidazolium polyoxometalates on intumescent flame retardant polypropylene

The role of dual imidazolium polyoxometalates (POMs) in the flame retardancy of polypropylene/intumescent flame retardant (PP/IFR) composites was studied. The results showed that the structures of dual imidazolium POMs have a great effect on the flame retardancy of PP composites. The dual imidazolium POMs based on an ethyl group (EMIPMA) obtain the best flame retardant efficiency. With 15.5 wt % IFR and 0.5 wt % EMIPMA, the PP composites reach a limiting oxygen index of 25.7 and the UL‐94 V‐0 standard. However, the dual imidazolium POMs containing a butyl (BMIPMA) or hexyl (HMIPMA) group cannot achieve the UL‐94 V‐0 standard at the same formulation. Dual imidazolium POMs not only promote the formation of good char, but also induce the formation of intumescent char with a hierarchical and microporous structure that helps to prevent gas and heat from transferring from the flame to the resin. Therefore, the flame retardancy of PP/IFR composites is improved. However, excessive combustible components produced by BMIPMA or HMIPMA deteriorate the flame retardancy of PP/IFR composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45491.     

Carbon nanotubes coated with phosphorus-nitrogen flame retardant and its application in epoxy thermosets

ABSTRACT

Carbon nanotubes coated with phosphorus-nitrogen flame retardant (PDAP-CNTs) were produced. The compositions and structures of PDAP-CNTs were systematically characterized, and the flame retardancy of PDAP-CNTs/EP composites were also tested. The results indicated that PDAP-CNTs demonstrated excellent flame retardancy performance on the flame-retardant EP composites (FR-EP), incorporation of 5.0wt% PDAP-CNTs improved the LOI values of EP from 26.0% to 31.8% and reached UL-94 V-0 classification. The analysis of flame-retardant mechanism indicating the flame-retardant ability of PDAP-CNTs was ascribed to the synergism of the phosphorus-nitrogen containing coating layer (PDAP) and CNTs.     

Synergistic effect of aluminum hydroxide and expandable graphite on the flame retardancy of polyisocyanurate–polyurethane foams

For the first time, expandable graphite (EG) and aluminum hydroxide (ATH) was combined to improve the flame retardancy of polyisocyanurate–polyurethane (PIR–PUR) foam. The limited oxygen index increased from 26.5 for the PIR–PUR matrix to an incredible value of 92.8 when 24 phr (parts per 100 of matrix) EG and 60 phr ATH were incorporated into the matrix. Based on morphology observation and thermogravimetric analysis, it was speculated that two factors contributed to the improvement of flame retardancy primarily. First, ATH could effectively induce “villi” like particles, which was useful to form a dense char. The compact char layer could effectively impede the transport of bubbles and heat. Second, ATH and EG accelerated the initial degradation and fluffy char was quickly generated on the surface of the composites. Thus, the degradation of the composite was slowed down and the diffusion of volatile combustible fragments to flame zone was delayed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39936.     

Boosting flame retardancy of epoxy resin composites through incorporating ultrathin nickel phenylphosphate nanosheets

Ultrathin nickel phenylphosphate (NiPP) nanosheets with layered structure are successfully synthesized through a mixed solvothermal method. The results indicate that NiPP is Ni(O₃PC₆H₅)·H₂O and has good thermal stability. To ameliorate the thermal stability and flame ratardancy of epoxy resin (EP), EP/NiPP nanocomposites are prepared by incorporating NiPP into EP matrix. The results show that adding NiPP can availably enhance thermal stability at high temperature due to the remarkable catalytic char performance of NiPP, and the residues yield of EP/NiPP nanocomposites with 6 wt% NiPP is 24.1% while the pure EP had only 14.2% at 700°C. In contrast with pure EP, the peak heat release rate, total heat release, smoke production rate, CO production, and CO₂ production of EP/6wt%NiPP nanocomposites reduced by 35.2%, 20.2%, 27.1%, 45.8%, and 35.5%. The synergistic effect of catalytic char performance and fire retardancy of NiPP make the EP/NiPP nanocomposites possess prominent flame retardancy, smoke suppression, and thermal stability.     

Improving flame retardancy and melt processability of polyethersulfone using low molecular weight additives

The effect of a calcium stearate (CaSt₂) additive on the melt processability and flame retardancy of polyethersulfone (PES) was studied. Measurements of the viscosity of PES and its composites showed a marked decrease in viscosity with increase in the fraction of CaSt₂ additive. About 40% reduction in viscosity of PES was achieved with addition of 5 wt % CaSt₂. By decreasing the viscosity, the CaSt₂ additive enabled the melt extrusion of PES at lower temperatures up to 90 °C below that of conventional melt processing. The flammability was also investigated using a Pyrolysis Combustion Flow Calorimeter (PCFC). The CaSt₂ additive resulted in tremendous improvement in the flame retardancy of PES as evident in the reduction of the heat release capacity (HRC) of the composites by up to 37%. Moreover, the peak of heat release rate (pHRR) of PES in the composites was up to 84% lower than in the neat polymer. The remarkable improvement in flame retardancy of PES was demonstrated to be related to the rapid charring of the composites and the in situ formation of calcium carbonate/calcium oxide upon decomposition of CaSt₂. The CaSt₂ additive was also found to enhance the flame retardancy of thermoplastics including polyamide‐6 and polypropylene (PP). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43525.     

Bioderived Bilayer Shell Modification β-FeOOH Nanorods via Self-Assembly Technique as Sustainable Flame Retardants for Enhancing Flame Retardancy of Epoxy Resin

The design and application of bioderived flame retardants have been widely conducted to meet the concept of green and sustainable development. Here, self-assembly technique is used to prepare core–shell bioderived additives by using β-FeOOH as the core and polydopamine (PDA)/tannic acid (TA) bilayer as the shell, following adsorption of nickel ions to enhance the thermal stability, flame retardancy, and mechanical properties of epoxy resin (EP). The molecular structure of biobased resources is rich in hydroxyl groups and carbon content, which can be dehydrated and carbonized during combustion and promote the formation of robust protective char layer. With the addition of 5 wt% β-FeOOH@PTNi, the EP composites can pass V-0 rating in the UL-94 test. The peak heat release rate and total heat release decrease by 28.4% and 17.4% compared with pure EP. The bioderived nanorods can capture the oxygen free radicals, contributing to flame retarding in gaseous phase. Thus, the release of high-toxic CO and flammable gaseous is significantly suppressed. Besides, the storage modulus of EP composites increases by 16.0% with the addition of 5% β-FeOOH@PTNi compared with pure EP. This work provides a sustainable methodology for the design of bioderived flame retardants for EP.     

TPS/EVA泡沫复合材料的制备及其阻燃与力学性能

以热塑性淀粉(TPS)为成炭剂与聚磷酸铵(APP)、可膨胀石墨(EG)复配组成膨胀型阻燃剂,通过熔融密炼、开炼塑化、硫化发泡制备了热塑性淀粉/乙烯-醋酸乙烯酯共聚物(TPS/EVA)泡沫复合材料,探讨了TPS用量对泡沫复合材料阻燃性能、力学性能的影响。结果表明,TPS的加入显著提高了TPS/EVA泡沫复合材料阻燃性能,可起到良好的成炭作用;TPS/EVA泡沫复合材料的拉伸强度、断裂伸长率以及撕裂强度随着TPS用量的增加呈现先增大后减小的趋势,相对密度则是小幅度上升。当TPS用量为6%时,TPS/EVA泡沫复合材料综合性能最好,其LOI可达26.5%且UL-94为V-0级,拉伸强度、断裂伸长率、撕裂强度以及相对密度可达2.395 MPa、177.48%、10.59 N·mm^-1、0.21452。     

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.     

Facile preparation and flame retardancy mechanism of cyclophosphazene derivatives for highly flame-retardant silicone rubber composites

A novel and efficient flame retardant cyclophosphazene derivative Hexa (p-acetamidophenoxy) cyclotriphosphazene (HACP) was successfully prepared via a facile one-step reaction. The chemical structure of HACP was characterized and confirmed by FT-IR, ¹H and ¹³C NMR. Then the as-prepared HACP was incorporated into addition-cure liquid silicone rubber (ALSR) matrix to prepare highly flame-retardant rubber composites. It was found that the incorporation of HACP can significantly enhance the flame resistance of ALSR. Typically, the ALSR composites filled with 30 phr HACP achieved UL-94 V-0 rating and meanwhile the total heat release and total smoke release were decreased by 26.9% and 41.5%, respectively. Moreover, the flame-retardant mechanism of ALSR/HACP composites was investigated by TGA, Py-GCMS, FT-IR, SEM and EDX, confirming that HACP plays a significant role in capturing free-radicals and forming protective layers. This work designed a novel cyclophosphazene-based flame retardant to significantly enhance the flame retardancy of ALSR, which may offer some valuable inspiration for the fabrication of highly flame-retardant polymer composites.     

Effect of talc on thermal stability and flame retardancy of polycarbonate/PSBPBP composite

A novel flame retardant poly(3-aminopropyl methylsiloxane bis(3-hydroxy phenyl spirocyclic pentaerythritol bisphosphate)) (PSBPBP) in combination with talc was blended into polycarbonate (PC) by melt compounding. The flame retardancy and thermal stability of PC/PSBPBP/talc composites were investigated by limiting oxygen index (LOI) test, UL-94 rating test, thermogravimetric analysis (TGA), Raman spectroscopy (RS), and scanning electron microscope (SEM). The mechanical properties were also measured in this work. Increasing talc content leads to observed improvement on flame retardancy of PC composites. LOI value of PC/PSBPBP/10 wt % talc system was 34, and this system passed V0 rating in the UL-94 test. The char yield at 700°C was 28.2% and the onset decomposition temperature shifted up to 540°C for PC/10% PSBPBP/10% talc system in TGA. In the Raman measure, the R value and G linewidth of PC/PSBPBP with 10 wt % talc composite increased to 1.41 and 65 cm⁻¹ from 1.12 and 43 cm⁻¹ of pure PC, respectively. The Raman results suggest that the char residue of PC/PSBPBP with talc composites was denser and had better barrier property, which is agreement with the SEM results. Besides, talc had no remarkable influence on the mechanical properties of PC/PSBPBP composites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

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.