Improvement of thermal stability and flame retardancy of polypolypropylene composite modified by ZnO and MoO3 nanowires

Herein, zinc oxide (ZnO) and molybdenum trioxide (MoO₃) nanowires were prepared via the hydrothermal method. Then as-prepared ZnO and MoO₃ nanowires were fabricated to form ZnO/MoO₃ compound nanostructure. ZnO/MoO₃ compounds were incorporated into polypropylene (PP) with various loadings by melt blending. The D-Optimal mixing design in Design-Expert software was employed to study the effects of ZnO/MoO₃ compound content on flame retardancy and mechanical properties of nanocomposites. Information on performance of thermal stability and flame retardancy of PP/ZnO/MoO₃ nanocomposites was obtained through thermogravimetric analysis, cone calorimeter tests, and limiting oxygen index (LOI). The results reflected that the synthesized ZnO/MoO₃ compound possessed high thermal stability and flame retardancy. The addition of 15 wt % ZnO nanowires and 13 wt % MoO₃ nanowires increased LOI from 18.2 to 23.0%. Meanwhile, the tensile strength of the PP/ZnO/MoO₃ nanocomposite decreased by 13.8% and the elongation at break of the PP nanocomposite increased by 20.4% compared with pure PP. Response surface analysis results also indicated that the loading of ZnO/MoO₃ compound had an influence on the mechanical properties and flame retardancy of PP. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48312.     

Low‐melting sulfate glasses as additives to semirigid PVC and their flame retardant and smoke suppressant properties

The role of low‐melting sulfate glasses (LMSG) as additives on the flame retardant and smoke suppressant properties of semirigid poly(vinyl chloride) (PVC), as well as the mechanism for flame retardancy and smoke suppression, were studied through the Limiting Oxygen Index (LOI) test. Smoke Density Rating (SDR) test, DTA‐TG, and SEM. The results show that the LMSG have good smoke suppressant properties. When the PVC compound contains 40 parts of LMSG, the SDR value will be reduced by about 45%. The Cu²⁺, Zn²⁺, Mn²⁺, and Ni²⁺ sulfates, as well as MoO₃, cause PVC to crosslink and form char, and the melt can protect not only the char formed during combustion and thermal degradation, but also undecomposed polymer. That is the main mechanism for flame retardation and smoke suppression when the additives melt. The mechanical properties of the PVC compounds containing different levels of LMSG were also studied.     

Preparation of expandable graphite with silicate assistant intercalation and its effect on flame retardancy of ethylene vinyl acetate composite

A halogen‐free intumescent flame retardant expandable graphite composite (EG), with an initial expansion temperature of 202°C and expansion volume of 517 mL g⁻¹, was successfully prepared via a facile two‐step intercalation method, i.e. using KMnO₄ as oxidant and H₂SO₄, Na₂SiO₃·9H₂O as intercalators. The prepared EG flame retardant was characterized by field emission scanning electron microscope, X‐ray diffraction spectroscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy. Furthermore, flame retardancy and thermal property of various ethylene vinyl acetate copolymer (EVA) composites, including EVA/EG and EVA/EG/APP (ammonium polyphosphate) specimens, were studied through limiting oxygen index instrument (LOI), vertical combustion UL‐94 rating, thermal gravimetric and differential thermal analysis. The results indicate that the EVA/EG and EVA/EG/APP composites exhibit a better flame retardancy. Addition of EG at a mass fraction of 30% leads LOI of 70EVA/30EG composite improved to 28.7%. Even more, the synergistic effect between EG and APP improves the LOI of 70EVA/10APP /20EG composite to 30.7%. This synergistic efficiency is attributed to the formation of compact and stable layer‐structure, and the prepared EG can make EVA composite reach the UL‐94 level of V‐0. POLYM. COMPOS., 36:1407–1416, 2015. © 2014 Society of Plastics Engineers     

Effect of boron‐containing materials on the flammability and thermal degradation of polyamide 6 composites containing melamine

Three different boron‐containing substances—zinc borate (ZnB), borophosphate (BPO₄), and a boron‐ and silicon‐containing oligomer (BSi)—were used to improve the flame retardancy of melamine in a polyamide 6 (PA‐6) matrix. The combustion and thermal degradation characteristics of PA‐6 composites were investigated with the limiting oxygen index (LOI), the UL‐94 standard, thermogravimetric analysis (TGA)/Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). A slight increase was seen in the LOI values of a sample containing BSi (1 wt %). BPO₄ at high loadings showed a V0 rating (indicating the best flame retardancy) and slightly lower LOI values in comparison with samples with only melamine. For ZnB and BSi, glassy film and char formation decreased the dripping rate and sublimation of melamine, and this led to low LOIs. According to the TGA–FTIR results, the addition of boron compounds did not change the decomposition product distribution of melamine and PA‐6. The addition of boron compounds affected the flame retardancy by physical means. The TGA data showed that boron compounds and melamine reduced the decomposition temperature of PA‐6. According to the DSC data, the inclusion of boron compounds increased the onset temperature of sublimation of melamine and also affected the flame retardancy negatively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of particle size on flame retardancy of Mg(OH)2‐filled ethylene vinyl acetate copolymer composites

Four kinds of magnesium hydroxide (Mg(OH)₂) with different particle sizes are chosen and mixed with ethylene vinyl acetate copolymer (EVA) to investigate the effect of particle size on the flame retardancy of composites, which is evaluated by limiting oxygen index (LOI) testing, horizontal fire testing, and cone calorimeter. When Mg(OH)₂ filling level changes from 35 to 70 wt %, the composites filled with nano‐Mg(OH)₂ do not always possess the best flame retardancy, and among the composites filled with micro‐Mg(OH)₂, the composites filled with 800 mesh Mg(OH)₂ show the best flame retardancy; however, the composites filled with 1250 mesh presents the worst one. So the effect of particle size on the flame retardancy of micro‐Mg(OH)₂‐filled EVA is not linear as expected. All the differences are thought to result from both particle size effect and distributive dispersion level of Mg(OH)₂. To prepare the composites with better mechanical properties and flame retardancy, authors suggested that Mg(OH)₂ of smaller size should be chosen as flame retardant, and good dispersion of Mg(OH)₂ particles also should be assured. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4461–4469, 2006     

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.     

A novel phosphorus‐containing copolyester with low melting temperature and high flame retardancy

BACKGROUND: The increasing uses of non‐woven fabrics need the development of a kind of novel flame‐retardant polyester with low melting temperature. Neopentyl glycol (NPG) and 3‐(hydroxyphenylphosphinyl)propionic acid (HPPPA) were used as the third and fourth comonomer to synthesize phosphorus‐containing poly[(ethylene terephthalate)‐co‐(neopentyl terephthalate)] (PENT) with both flame retardancy and low melting temperature. RESULTS: The chemical structure of PENT was confirmed using Fourier transform infrared, ¹H NMR, ¹³C NMR and ³¹P NMR spectroscopy. PENT displays a monomodal gel permeation chromatography curve. When the content of NPG was kept at 10 wt% and the content of HPPPA increased to 5 wt%, the melting temperature (T_m) of the resulting PENT5/10 decreases to 171.2 °C, a 34.6 °C decrease compared to that of PENT0/10 (containing no HPPPA). The flammability of the PENTs was characterized with the limiting oxygen index (LOI) test, the UL‐94 vertical test and the cone calorimeter test. The incorporation of HPPPA can significantly improve the flame retardancy of the PENTs, the LOI values of the PENTs increasing from 24.4 to 37.6, as the loading of HPPPA increases from 0 to 5 wt%. CONCLUSION: The PENTs possess both low melting temperatures and excellent flame retardancy. HPPPA can be used as fourth comonomer to improve the flame retardancy of the PENTs, while decreasing the T_m value of the copolyester. Copyright © 2009 Society of Chemical Industry     

Effects of ammonium polyphosphate and triphenyl phosphate on the flame retardancy,thermal, and mechanical properties of glass fiber–reinforced PLA/PC composites

The purpose of this study is to increase of the flammability properties of the glass fiber (GF)–reinforced poly (lactic acid)/polycarbonate (PLA/PC) composites. Ammonium polyphosphate (APP) and triphenyl phosphate (TPP) were used as flame retardants that are including the organic phosphor to increase flame retardancy of GF‐reinforced composites. APP, TPP, and APP‐TPP mixture flame retardant including composites were prepared by using extrusion and injection molding methods. The properties of the composites were determined by the tensile test, limiting oxygen index (LOI), differential scanning calorimetry (DSC), and heat release rate (HRR) test. The minimum T_g value was observed for the TPP including PLA/PC composites in DSC analysis. The highest tensile strength was observed in GF‐reinforced PLA/PC composites. In the LOI test, GF including composite was burned with the lowest concentration of oxygen, and burning time was the longest of this composite. However, the shortest burning time was obtained by using the mixture flame retardant system. The flame retardancy properties of GF‐reinforced PLA/PC composite was improved by using mixture flame retardant. When analyzed the results of HRR, time to ignition (TTI), and mass loss rate together, the best value was obtained for the composite including APP.     

Novel flame retardant thermosets from nitrogen‐containing and phosphorus‐containing epoxy resins cured with dicyandiamide

A novel phosphorus‐containing epoxy resin (EPN‐D) was prepared by addition reaction of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene 10‐oxide (DOPO) and epoxy phenol‐ formaldehyde novolac resin (EPN). The reaction was monitored by epoxide equivalent weight (EEW) titration, and its structure was confirmed by FTIR and NMR spectra. Halogen‐free epoxy resins containing EPN‐D resin and a nitrogen‐containing epoxy resin (XT resin) were cured with dicyandiamide (DICY) to give new halogen‐free epoxy thermosets. Thermal properties of these thermosets were studied by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), thermal mechanical analyzer (TMA) and thermal‐gravimetric analysis (TGA). They exhibited very high glass transition temperatures (T_gs, 139–175°C from DSC, 138–155°C from TMA and 159–193°C from DMA), high thermal stability with T_{d,5 wt %} over 300°C when the weight ratio of XT/EPN‐D is ≥1. The flame‐retardancy of these thermosets was evaluated by limiting oxygen index (LOI) and UL‐94 vertical test. The thermosets containing isocyanurate and DOPO moieties showed high LOI (32.7–43.7) and could achieve UL‐94 V‐0/V‐1 grade. Isocyanurate and DOPO moieties had an obvious synergistic effect on the improvement of the flame retardancy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Fabrication and properties of PEI/APP layer-by-layer coated ramie fabric combined with low-temperature plasma treatment

The present work demonstrates a surface pretreatment of reducing assembly layers for flame retardant modification of ramie fabric used by layer-by-layer (LbL) assembly. In order to achieve this goal, low-temperature plasma (LTP) pretreatment was chosen. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscope (SEM) were used to confirm the effect of LTP pretreatment on polyethylenimine/ammonium polyphosphate (PEI/APP) flame retardant coating constructed on the surface of ramie fabric using LbL assembly. The thermal property and flame retardancy of PEI/APP coated ramie fabrics were analyzed by TG, LOI, UL94 vertical burning, and cone calorimeter tests. The results indicated that the decomposition rate of ramie fabrics was reduced and the char forming ability at high temperature was improved by PEI/APP coating on the ramie surface. Its LOI increased markedly to 30.6% and ramie fabric achieved self-extinguishing effect. Meanwhile, LTP-O₂-(PEI/APP)₂₀ ramie fabric exhibited the low flammability and high fire safety. It was proved that LTP pretreatment under oxygen atmosphere could endow ramie fabric with better flame retardancy due to more PEI/APP adsorbed on its surface. These findings have significant implications for the application of LTP pretreatment to flame retardant modification of ramie fabric by LbL assembly.     

Surface photografting: New application for flame retardant finishing of polyamide6.6 (PA6.6) fabric

Surface photografting modification with maleic anhydride (MAn) under UV irradiation in association with a post reaction with triethanolamine has been used to improve the flame retardancy of polyamide6.6 (PA6.6) fabric in this study. The effects of irradiation time and monomer concentration on the fabric surface grafting were investigated. The flame retardancy and thermal decomposition behavior of the samples were characterized by limiting oxygen index test (LOI), thermogravimetric analysis (TGA), and differential scanning calorimetric (DSC), and the results indicate that flame retardancy of the treated PA6.6 fabric samples has been significantly improved. The chemical structures of the treated samples' surface were characterized by attenuated total reflection infrared spectroscopy (ATR‐FTIR), and the possible photochemical mechanisms were discussed. It is suggested that this could be the first time to use photografting technology to enhance the flame retardancy of PA6.6 fabric. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of silicon additive as synergists of Mg(OH)2 on the flammability of ethylene vinyl acetate copolymer

The present work dealt with the effects of nine kinds of silicon additives on flame retardancy of ethylene‐vinyl acetate copolymer (EVA)/magnesium hydroxide [Mg(OH)₂] composites, as well as mechanical properties. The limiting oxygen index (LOI) test, horizontal fire test, vertical fire test, and cone calorimeter test were employed to evaluate flame retardancy of the composites. It was found that different silicon additives had different synergistic effects with Mg(OH)₂ on flame retardancy of the EVA matrix and exerted different influences on mechanical properties of the composites. The incorporation of organic montmorillonite (MMT) clay or silicone rubber not only made the composite reach FH‐1 rating in the horizontal fire test and FV‐1 rating in the vertical fire test, respectively, but also dramatically reduced the peak rate of heat release (Peak RHR) and increased the fire performance index (FPI) and ignition time (IT). The composites filled with precipitated SiO₂ exhibited the longest IT, the highest FPI, and FV‐1 rating. However, only the composites filled with silicone rubber could attain a balance between mechanical properties and flame retardancy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

A formaldehyde‐free flame retardant wood particleboard system based on two‐component polyurethane adhesive

To address the problem of formaldehyde‐free flame retardation of wood particleboard, a novel phosphorus‐containing compound, di(2,2‐dimethyl‐1,3‐propanediol phosphate) urea (DDPPU) was synthesized. DDPPU was used as flame retardant for wood particleboard. The flammability of treated wood particleboard systems consisted of wood particles, polyurethane (PU) adhesive, and different flame retardant formulations were investigated by limiting oxygen index (LOI). The results of LOI indicate that DDPPU could improve the flame retardancy of wood particleboard. However, when H₃BO₃ was used as the second flame retardant component and combined with DDPPU, the flame retardant wood particleboard could obtain the highest LOI value (46.0) in these experiments. Thermogravimetric analysis shows that treated wood particleboard can decrease the initial decomposition temperature, and that at higher temperatures the degradation rate are lower than the untreated wood particleboard. Furthermore, wood particleboard treated with DDPPU/H₃BO₃ has a higher yield of residue char at 600°C than that treated with other flame retardant systems. The ability of char formation of these samples agrees with the order of LOI values. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Structure−property relationships of halogen‐free flame‐retarded poly(butylene terephthalate) and glass fiber reinforced PBT

Flame retardancy for thermoplastics is a challenging task where chemists and engineers work together to find solutions to improve the burning behavior without strongly influencing other key properties of the material. In this work, the halogen‐free additives aluminum diethylphosphinate (AlPi‐Et) and a mixture of aluminum phosphinate (AlPi) and resorcinol‐bis(di‐2,6‐xylyl phosphate) (AlPi‐H + RXP) are employed in neat and reinforced poly(butylene terephthalate) (PBT), and the morphology, mechanical performance, rheological behavior, and flammability of these materials are compared. Both additives show submicron dimensions but differ in terms of particle and agglomerate sizes und shapes. The overall mechanical performance of the PBT flame‐retarded with AlPi‐Et is lower than that with AlPi‐H‐RXP, due to the presence of larger agglomerates. Moreover, the flow behavior of the AlPi‐Et/PBT materials is dramatically changed as the larger rod‐like primary particles build a percolation threshold. In terms of flammability, both additives perform similar in the UL 94 test and under forced‐flaming combustion. Nevertheless, AlPi‐Et performs better than AlPi‐H + RXP in the LOI test. The concentration required to achieve acceptable flame retardancy ranges above 15 wt %. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis of carborane acrylate and flame retardant modification on silk fabric via graft copolymerization with phosphate‐containing acrylate

A novel carborane acrylate monomer (1‐acryloyloxyethyl carborane) was synthesized by addition reaction, hydrolysis, and esterification and characterized by proton nuclear magnetic resonance (¹H NMR) spectroscopy and Fourier transform infrared spectroscopy (FT‐IR) analysis. Subsequently, the carborane monomer and a phosphate‐containing methacrylate monomer were applied on the modification of a silk fabric. The heat resistance and flame retardancy of the silk fabric before and after modification were compared. Energy‐dispersive X‐ray spectrometer (EDS) and FT‐IR showed that carborane monomer and phosphate‐containing methacrylate were grafted onto the surface of the fibers. The cross‐sectional morphology of silk fabrics after burning was observed by scanning electron microscope (SEM), and the flame‐retardant mechanism was analyzed. Thermal‐gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis revealed that the thermal stability of the modified silk increased with the increase of the grafting yield. The MCC‐2 microcalorimeter (MCC) test showed that, when using 1‐acryloyloxyethyl carborane as monomer and blending with phosphate‐containing methacrylate, the maximum heat release rate (PHRR) of the modified silk fabric decreased from 97.6 W/g (before grafting) to 51.3 and 45.8 W/g, respectively, and the total heat release (THR) decreased from 10.2 kJ/g (before grafting) to 5.9 and 5.2 kJ/g, respectively. The limiting oxygen index (LOI) test revealed that using 1‐acryloyloxyethyl carborane and phosphate‐containing methacrylate as mixed monomers to modify the silk fabric obtained good flame retardancy, whose LOI value reached 29.8%.     

Effect of zinc oxide on properties of phenolic foams/halogen‐free flame retardant system

A halogen‐free flame retardant system consisting of ammonium polyphosphate (APP) as an acid source, blowing agent, pentaerythritol (PER) as a carbonific agent and zinc oxide (ZnO) as a synergistic agent, was used in this work to enhance flame retardancy of phenolic foams. ZnO was incorporated into flame retardant formulation at different concentrations to investigate the flammability of flame retardant composite phenolic foams (FRCPFs). The synergistic effects of ZnO on FRCPFs were evaluated by limited oxygen index (LOI), thermogravimetric analysis (TGA), cone calorimeter tests, and images of residues. Results showed that the flame retardant significantly increased the LOI of FRCPFs. Compared with PF, heat release rate (HRR), total heat release (THR), effective heat of combustion (EHC), production or yield of carbon monoxide (COP or COY) and Oxygen consumption (O₂C) of FRCPFs all remarkably decreased. However specific extinction area (SEA) and total smoke release (TSR) significantly increased, which agreed with the gas‐phase flame retardancy mechanism of the flame retardant system. The results indicated that FRCPFs have excellent fire‐retardant performance and less smoke release. And the bending and compression strength were decreased gradually with the increase of ZnO. The comprehensive properties of FRCPFs were better when the amount of ZnO was 1～1.5%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42730.     

Enhanced flame retardancy of unsaturated polyester resin composites containing ammonium polyphosphate and metal oxides

Three metal oxides (MOs) (Fe₂O₃, Sb₂O₃, Al₂O₃) were incorporated into blends of unsaturated polyester resin (UPR)/ammonium polyphosphate (APP) composites with the aim of studying and comparing their synergistic effect on flame retardancy with APP. The UPR-APP/MOs composites were prepared, then the thermal stability and flame-retardant properties of the UPR composites were evaluated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical burning test (UL-94), and cone calorimetry test (CCT). Besides, residues after CCT were characterized by scanning electron microscopy and laser Raman spectroscopy. The LOI values of the UPR composites with 0.5 wt% MOs increased to around 40%. However, the CCT results indicated that the incorporation of Sb₂O₃ brought an increase in the total heat release. Moreover, these three MOs had different effects on the process of thermal degradation of UPR composites from the TGA results. Based on the above results, Al₂O₃ provided a best promotion on flame retardancy among three MOs.     

Synergistic flame retardant effects of activated carbon and molybdenum oxide in poly(vinyl chloride)

The synergistic effects of activated carbon (AC) and molybdenum oxide (MoO₃) in improving the flame retardancy of poly(vinyl chloride) (PVC) were investigated. The effects of AC, MoO₃ and their mixture with a mass ratio of 1:1 on the flame retardancy and smoke suppression properties of PVC were studied using the limiting oxygen index and cone calorimeter tests. It was found that the flame retardancy of the relatively cheaper AC was slightly weaker than that of MoO₃. In addition, the incorporation of AC and MoO₃ greatly reduced the total heat release and improved smoke suppressant property of PVC composites. When the total content of AC and MoO₃ was 10 phr, PVC/AC/MoO₃ had the lowest peak heat release rate and peak smoke production rate values of 173.80 kW m^?2 and 0.1472 m² s^?1, which represented reductions of 47.3 and 59.9%, respectively, compared with those of PVC. Furthermore, thermogravimetric analysis and gel content tests were used to analyze the flame retardant mechanism of AC and MoO₃, with results showing that AC could promote early crosslinking in PVC. Char residue left after heating at 500 °C was analyzed using scanning electron microscopy and Raman spectroscopy, and the results showed that MoO₃ produced the most compact char, with the smallest and most organized carbonaceous microstructures. © 2017 Society of Chemical Industry     

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 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