Study on flame retardancy of APP/PEPA/MoO3 synergism in vinyl ester resins

A range of flame retardant vinyl ester resins (VERs) samples have been produced containing different contents of PEPA (1-oxo-4-hydroxymethyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane), APP (ammonium polyphosphate), and MoO₃ (molybdenum trioxide). By investigating the flame retardancy of VER samples such as limiting oxygen index and UL-94, the synergistic flame retardance of APP, PEPA, and MoO3 has been revealed. The cone calorimeter is an instrument that measures the combustion data of samples. In the VER composites on fire, the synergistic smoke suppression effect of the APP, PEPA, and MoO₃ was detected. The gas and condensed phase of VER composites with APP, PEPA, and MoO₃ were tested by the thermogravimetric analysis (TGA)–Fourier transform infrared spectroscopy (FTIR) and FTIR. The char residues of samples have been studied at length by scanning electron microscopy and FTIR. The results show that the presence of MoO3 can promote the formation of P O and PO structures.     

壳聚糖/聚磷酸铵膨胀阻燃PP的阻燃及抑烟性能

为了提高聚丙烯(PP)的阻燃和抑烟性能,将壳聚糖(CS)作为膨胀型阻燃剂的碳源、聚磷酸铵(APP)作为膨胀型阻燃剂的酸源和气源,在此基础上通过熔融共混的方法制备了PP/CS/APP复合材料。采用极限氧指数仪、锥形量热仪等仪器研究了PP/CS/APP复合材料的的抑烟性及阻燃性。研究结果表明:CS/APP添加量为30%时,复合材料的极限氧指数值最大可达28.1%;且复合材料在烟气释放总量、CO和CO_2排放上明显降低,抑烟性得到了提升;热释放速率峰值、平均热释放速率值、平均有效燃烧热值、总热释放量值降低,成炭率升高,PP/CS/APP复合材料更难点燃;火灾性能指数明显提高,阻燃性能得到了大幅度提升,火灾蔓延指数显著减小,同时火灾危险性也相应降低。     

Flame retardant and mechanical properties of epoxy composites containing APP−PSt core−shell microspheres

Ammonium polyphosphate (APP)–polystyrene (PSt) core–shell microspheres (CSPs) were synthesized via in situ radical polymerization. The core–shell structure was confirmed by transmission electron microscope (TEM). The results of optical contact angle measurements demonstrated a significant improvement in hydrophobicity of the modified APP. The obtained APP–PSt CSPs were added into epoxy (EP) system with various loadings. Effects of CSP on flame retardancy, thermal properties, heat release rate (HRR), smoke production, and mechanical properties of EP/CSP composites were investigated by limiting oxygen index (LOI), UL‐94 tests, thermogravimetric analysis (TGA), cone calorimeter, and tensile test. LOI and UL‐94 indicated that CSP remarkably improved the flame retardancy of EP composites. TGA showed that the initial decomposition temperature and the maximum‐rate decomposition temperature decreased, whereas residue yields at high temperature increased with the incorporation of microspheres. Cone calorimetry gave evidence that HRR, peak release rate, average HRR, and smoke production rate of EP/CSP composites decreased significantly. The morphology of char residues suggested that CSP could effectively promote EP to form high‐quality char layer with compact outer surface and swollen inner structure. Tensile strength of EP was enhanced with the addition of CSP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40218.     

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.     

Fire retardant properties of intumescent polypropylene composites filled with calcium carbonate

This study was aimed to investigate the influence of calcium carbonate (CaCO₃), a widely used filler, on the fire retardancy of intumescent polypropylene composites. Two intumescent systems based on (1) mixture of ammonium polyphosphate (APP) and pentaerythritol and (2) surface‐modified APP (m‐APP) were examined. In terms of steady heat release rate, total heat evolved, and fire growth index determined by mass loss calorimetry, m‐APP performed markedly superior to APP‐pentaerythritol. The presence of CaCO₃ in both intumescent formulations caused significant losses in fire retardant performance assessed by mass loss calorimetry, limiting oxygen index and UL‐94 tests. Peak rates of heat release and mass loss during combustion, and total heat evolved on combustion were increased, whereas time to ignition was decreased. Characterization of fire residues ascribed the mechanism of deterioration in fire retardancy to the formation of porous and nonexpanded crystalline calcium phosphate/CaCO₃ residues during combustion rather than the amorphous protective intumescent chars formed in the absence of CaCO₃. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

四溴双酚-A阻燃体系在HIPS／OMMT复合材料中的阻燃性研究

采用熔融插层法分别制备高抗冲苯乙烯／有机蒙脱土（HIPS／OMMT）复合材料和四溴双酚-A／三氧化二锑（TBBPA—Sb2O3）体系阻燃的HIPS／OMMT复合材料,透射电镜研究表明,有机蒙脱土均匀地分散于HIPS基体当中,形成了插层复合结构,锥形量热仪和氧指数仪研究表明：与纯的HIPS相比,HIPS／OMMT复合材料的阻燃性和抑烟性有所提高,但阻燃性的提高幅度较有限：与仅添加OMMT时的HIPS／OMMT复合材料相比,添加相同量OMMT时TBBPA—Sb2O3体系阻燃的HIPS／OMMT复合材料的热释放速率（HRR）和热释放速率峰值（PHRR）均有所降低,氧指数有所增加,且随TBBPA—Sb2O3阻燃剂添加量的增加阻燃性能的提高越明显,但TBBPA—Sb2O3的加入会导致聚合物燃烧过程生烟速率和生烟量的显著增加．因此此类阻燃剂的加入量不宜过高。     

Flame-retardant properties and synergistic effect of ammonium polyphosphate/aluminum hydroxide/mica/silicone rubber composites

The flammability behaviors of ammonium polyphosphate/aluminum hydroxide/mica/silicone rubber (APP/Al[OH]₃/mica/SiR) ceramifying composites containing APP, Al[OH]₃, and mica are investigated by cone calorimeter test. The thermal degradation and the synergistic effect of APP/Al(OH)₃/mica/SiR composites are investigated by thermal gravimetric analysis, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. APP/Al(OH)₃/mica/SiR composites with 25 wt% of APP, 20 wt% of Al(OH)₃, 25 wt% of mica, and 30 wt% SiR presents a much lower total heat release, the value of peak heat release rate (PHRR), the maximum average heat release rate, the longest time to ignition, and time to the PHRR (t_PHRR), compared with the flame-retardant properties from composites with filler of APP and mica or APP and Al(OH)₃ alone. The results indicate that there is an excellent synergism in APP, Al(OH)₃, and mica, which endows APP/Al(OH)₃/mica/SiR composites with both good flame retardancy and fire prevention. The study on the synergism effect between fire prevention and flame retardancy of APP/Al(OH)₃/mica/SiR composites indicates that compounds containing P-O-Al are formed due to the reaction between APP and Al(OH)₃ during combustion in the early stage and a coherent, dense, and sealed structure is formed due to the reaction in mica, phosphates, and the thermal decomposition products of SiR during combustion in the later stage.     

动态熔融插层HIPS/蒙脱土复合材料阻燃性能的研究

采用动态熔融法分别制备高冲击强度聚苯乙烯/有机蒙脱土(HIPS/OMMT)复合材料和高冲击强度聚苯乙烯/钠基蒙脱土(HIPS/Na+-MMT)复合材料,利用锥形量热仪测试复合材料的阻燃性能,结果表明:HIPS/OMMT复合材料的热释放速率(HRR)、生烟速率(SPR)、质量损失速率(MLR)等燃烧性能参数均明显降低,表现出较好的阻燃性和抑烟性;Na+-MMT阻燃HIPS与OMMT阻燃HIPS复合材料比较,HIPS/OMMT复合材料的阻燃性明显优于HIPS/Na+-MMT。通过研究复合材料的阻燃性能,结合燃烧残余物的微观结构和宏观形貌分析,探讨了复合材料的阻燃机理。     

Smoke and toxicity suppression by zinc salts in flame‐retardant polyurethane‐polyisocyanurate foams filled with phosphonate and chlorinated phosphate

Three types of zinc salts, ZnAl₂O₄, ZnFe₂O_4, and Zn₂SiO_4, were prepared by coprecipitation. Potential smoke and toxicity suppression by zinc salts in flame‐retardant polyurethane‐polyisocyanurate foams (FPUR‐PIR) with dimethylmethylphosphonate (DMMP) and tris (2‐chloropropyl) phosphate (TCPP) were investigated. The crystal structure and dispersity of zinc salts in FPUR‐PIR were characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Smoke density, flame retardancy, and thermal degradation were studied using smoke density rating (SDR), limiting oxygen index (LOI), the cone calorimeter test, and thermogravimetry coupled with FTIR spectrophotometry (TGA‐FTIR). The results indicated that pure zinc salts were obtained and evenly dispersed on the cell wall of FPUR‐PIR. SDR and the specific extinction area (SEA) were significantly decreased, the time to second heat release rate peak (pk‐HRR) of FRUP‐PIR was delayed after incorporation of the zinc salts; zinc salts partially inhibited phosphorus oxide release into the gas phase, enhanced the condensed phase effect of phosphorus, reduced, and prolonged the release of isocyanate compound and hydrogen cyanide from FRUP‐PIR; due to an increase in the amount of char residues, which indicated the suppression of smoke and toxicity volatiles. ZnFe₂O₄ resulted in better char formation at the initial degradation stage of FPUR‐PIR, and ZnAl₂O₄ retained more phosphorus in the solid phase at higher temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41846.     

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.     

Flammability of EVA/IFR (APP/PER/ZB system) and EVA/IFR/synergist (CaCO3, NG,and EG) composites

Poly(ethylene‐co‐vinyl acetate)/intumescent flame retardant (ammonium polyphosphate/pentaerythritol/zinc borate system) composites‐EVA/IFR (APP/PER/ZB system) and EVA/IFR/Synergist [CaCO₃, natural graphite, or expanded graphite (EG)] composites have been prepared by melting compounding method. The flammability, the combustion process, the quantity of the residual chars, the morphology of the residual chars, and the thermal stability of the chars have been investigated by cone calorimeter, scanning electron microscopy and thermo gravimetric analysis. The results indicate that heat release rate (HRR), total heat released, and total smoke release (TSR) of EVA/IFR (IFR 30 phr) composite decrease to about 67.1, 78.2, and 64% of that of pure EVA, respectively. HRR, THR, and TSR of EVA/IFR/EG (IFR 9 phr, EG 1phr) composite decrease to about 62.1, 76.2, and 44% of that of pure EVA, respectively. The quantity, the thermal stability of residual chars and the char structure are discussed to find the reasons of the phenomenon above. It has been found that the flame retardant of EVA vulcanizates is improved and the fire jeopardizing is dramatically reduced due to the addition of IFR and synergist, which can give some advice to design formulations for practical applications as cable. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

低烟无卤阻燃HIPS的研究

采用熔融法制备包括有机蒙脱土（OMMT）、红磷（RP）和酚醛树脂（PFR）体系的阻燃高抗冲聚苯乙烯（HIPS）复合材料，用基于耗氧原理的锥形量热仪研究复合材料的阻燃性能，用扫描电子显微镜观察了复合材料燃烧残余物的微观结构形态。结果表明，与纯HIPS相比，制备的HIPS／OMMT复合阻燃材料阻燃性能有所提高，但提高幅度有限；与HIPS／OMMT复合阻燃材料相比，添加RP和PFR的阻燃RP／PFR／HIPS／OMMT复合材料的热释放速率及其峰值、质量损失速率和生烟速率等燃烧性能参数继续降低，且火灾性能指数大幅提高，表现出低烟和高效的阻燃特点。     

纳米阻燃抑烟PVC的研究进展

PVC是一种应用广泛的高分子材料,但因其具有热稳定性差、易燃烧、发烟量大的缺点而限制了发展,因此PVC的阻燃与抑烟成为阻燃科学研究领域的关键问题之一。纳米型阻燃抑烟剂克服了传统型阻燃抑烟剂添加量大、阻燃抑烟效果不明显的缺点,为研究和解决PVC阻燃抑烟提供了一个新途径。本文介绍了PVC纳米阻燃抑烟剂的制备方法、表征手段及其在PVC中的应用以及PVC降解、阻燃与抑烟的表征,最后简要论述PVC阻燃抑烟的发展趋势。     

海泡石与APP对PVC/竹粉复合材料的阻燃抑烟机理

将海泡石(SEP)和聚磷酸铵(APP)同时加到聚氯乙烯(PVC)/竹粉复合材料中,考察SEP和APP对复合材料的协效阻燃抑烟作用及力学性能的影响。结果表明,在锥形量热实验中,热释放速率峰值相对减少42.8%,平均热释放速率和总热释放量相对减少29.5%和25.7%,总烟释放量相对降低了12.2%,一氧化碳平均产率相对降低了42.0%;扫描电子显微镜分析发现,APP具有催化成炭并形成膨胀泡沫炭层的作用,而SEP具有吸附聚集诱导成炭的作用;APP的阻燃机理主要属于气相阻燃机理,SEP的阻燃机理主要属于凝聚相阻燃机理;弯曲性能测试结果表明,SEP与APP对PVC/竹粉复合材料具有协同颗粒增强作用;拉伸性能测试结果表明,SEP对PVC/竹粉复合材料的塑性变形能力的损害比APP小。因此,SEP与APP联用能够对PVC/竹粉复合材料进行有效的阻燃抑烟,同时也能增强复合材料的力学性能。     

Study of Fire Retardancy and Thermal and Mechanical Properties of HDPE-Wood Composites

This article reports a study of flame retardancy and thermal and mechanical properties of wood-plastic composites (WPCs) based on high-density polyethylene and pine flour. The study shows that sample composition plays an important role in WPCs' properties. The influence of additives like fillers (SiO₂ or CaCO₃) and flame retardants ammonium polyphosphate (APP) and pentaerythritol (PER) on WPCs' properties has been considered. The best properties are shown in samples using SiO₂ as filler and treated with the intumescent fire retardant APP/PER. Such samples have excellent fire retardancy with V-0 rating (UL-94 test) and imply that APP/PER fire retardant ensures effective fire retardancy for WPCs.     

Synergistic flame retardant effects of ammonium polyphosphate in ethylene‐vinyl acetate/layered double hydroxides composites

Mg–Al–Fe ternary layered double hydroxides (LDH) were synthesized based on bayer red mud by calcination‐rehydration method, and characterized using X‐ray diffraction and thermogravimetric analysis (TGA). The synergistic flame retardant effects of ammonium polyphosphate (APP) with LDH in ethylene‐vinyl acetate (EVA) composites were studied using limiting oxygen index (LOI), UL 94 test, cone calorimeter test (CCT), and smoke density test (SDT). The thermal degradation behavior of EVA/LDH/APP composites was examined by thermal gravimetric analysis‐fourier transform infrared spectrometry (TG‐FTIR). The results showed that LOI values decreased by incorporation of APP together with LDH; and, a suitable amount of APP in EVA/LDH composites can apparently improve UL 94 rating. The CCT results indicated that heat release rate (HRR) of the EVA/LDH/APP composites with APP decreased in comparison with that of the EVA/LDH composites. The SDT results showed that APP was helpful to suppress smoke. The TG‐FTIR data showed that the composites with APP had a higher thermal stability than the EVA/LDH composites at high temperature. POLYM. ENG. SCI., 54:766–776, 2014. © 2013 Society of Plastics Engineers     

Synthesis of novel triazine charring agent and its effect in intumescent flame‐retardant polypropylene

A novel charring agent (CNCA‐DA) containing triazine and benzene ring, using cyanuric chloride, aniline, and ethylenediamine as raw materials, was synthesized and characterized. The effects of CNCA‐DA on flame retardancy, thermal degradation, and flammability properties of polypropylene (PP) were investigated by limited oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis (TGA), and cone calorimeter test (CCT). The TGA results showed that CNCA‐DA had a good char forming ability, and a high initial temperature of thermal degradation; the char residue of CNCA‐DA reached 18.5% at 800°C; Ammonium polyphosphate (APP) could improve the char residue of APP/CNCA‐DA system, the char residue reached 31.6% at 800°C. The results from LOI and UL‐94 showed that the intumescent flame retardant (IFR) containing CNCA‐DA and APP was very effective in flame retardancy of PP. When the mass ratio of APP and CNCA‐DA was 2 : 1, and the IFR loading was 30%, the IFR showed the best effect; the LOI value reached 35.6%. It was also found that when the IFR loading was only 20%, the flame retardancy of PP/IFR can still pass V‐0 rating in UL‐94 tests, and its LOI value reached 27.1%. The CCT results demonstrated that IFR could clearly change the decomposition behavior of PP and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke production (TSP), and mass loss (ML). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synergistic effects of molybdenum disulfide on a novel intumescent flame retardant polyformaldehyde system

A novel intumescent flame retardant (IFR) composed of ammonium polyphosphate (APP), benzoxazine containing trialkoxysilane (BA-a-Si) and melamine (ME), is compounded with different specifications of MoS₂ as synergist to flame retard polyformaldehyde (POM). The flame retardancy and mechanism of the composites are analyzed by limiting oxygen index (LOI), vertical combustion (UL-94) and cone calorimeter. At the same time, the mechanical properties and lubricating properties are tested by electromechanical testing machine and wear testing machine. The experimental results show that MoS₂ has a good synergistic effect with IFR, and the smaller the average particle size of MoS₂ is, it seems to be more beneficial to improve the flame retardancy of POM composites. Only a small amount of MoS₂ (0.8 wt%) is needed to synergize with IFR, the flame retardant POM composite (FR-POM) can achieve UL-94 (3.2 mm) V-0 rating, LOI of 62.5%, and heat release rate reduction of 25.3%, total smoke release decreased by 29.5%. In addition, from the mechanical properties analysis, it is found that the microscale MoS₂(M2) can better improve the bending and tensile properties of the FR-POM composites, while the nanoscale MoS₂(N80) is more helpful to improve the lubricating properties.     

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     

Improving the Flame Retardancy and Smoke Suppression of Poly(Lactic Acid) with a SiO2@ammonium Molybdate Core-Shell Nanotubes

Design and fabrication of SiO₂@ammonium molybdate(AM) core-shell nanotubes are important for polylactic acid (PLA), these two components form a well-defined core-shell configuration that is distinct from simple core-shell or hybrid structures. The PLA was investigated by limiting oxygen index, vertical burning test and smoke density, cone calorimeter test, SEM and TGA. The results showed that SiO₂@AM nanotube can effectively increase the flame retardancy and smoke suppression properties, and that it can apparently reduce heat release rate, total heat release and total smoke release. Furthermore, the addition of SiO₂@AM nanotube brings better mechanical properties than the sample contain SiO₂ nanotube. Here, SiO₂@AM nanotube was considered to be an effective flame retardant in PLA.