Flame retardancy of glass fiber reinforced high temperature polyamide by use of aluminum diethylphosphinate: thermal and thermo‐oxidative effects

Glass fiber reinforced polyamide (PA) 6 T/DT flame retarded with aluminum diethylphosphinate (AlPi) was tested to assess its flame retardant properties. Models for the decomposition of PA 6T/DT with and without AlPi are presented. Thermal decomposition was measured by performing TGA with Fourier transform infrared (FTIR) spectroscopy and FTIR spectroscopy in the condensed phase. Fire behavior was studied using a cone calorimeter and flammability was tested with UL 94 and the limiting oxygen index. AlPi works as an effective flame retardant for glass fiber reinforced PA 6T/DT materials, acting in the gas phase. Also observed was condensed‐phase action, which occurs especially under oxidative conditions before the samples ignite. © 2013 Society of Chemical Industry     

硅酸盐阻燃木材的阻燃性能和热性能研究

通过二次浸渍工艺获得了硅酸盐阻燃木材样品,通过极限氧指数(LOI)测试了样品的阻燃性能,通过热分析结合扫描电子显微镜(SEM)研究了样品的热降解过程。结果表明:通过二次浸渍工艺可获得阻燃性能优良的阻燃木材,过渡金属硅酸盐可有效的催化木材第二阶段的降解反应,促进炭的生成,还可以在高温下形成熔体覆盖在剩炭的表面,有效提高剩炭的稳定性,同时隔绝可燃性气体的逸出,避免热量和O2的进入,使木材具有良好的阻燃性能。     

Synergistic effects of aluminium hypophosphite on the flame retardancy and thermal degradation behaviours of a novel intumescent flame retardant thermoplastic vulcanisate composite

ABSTRACT

The synergistic effects of aluminum hypophosphite (AHP) on the flame retardancy, thermal degradation behaviors of a novel intumescent flame retardant thermoplastic vulcanizate (TPV/IFR) composite were investigated. The results showed that the combination of AHP with IFR showed evident synergistic effects on the increase in the LOI value and reduction of the combustion parameters for the TPV/IFR/AHP composites at the optimum weight ratio of IFR/AHP (6/1) as evidenced by LOI, UL-94 and CCT. The TGA data revealed that AHP could change the degradation behavior of TPV/IFR composites and enhance the thermal stability of the TPV/IFR composites at high temperature. The results of FTIR, EDXS, LRS and SEM demonstrated that TPV/IFR/AHP composites could form more continuous, dense and stable char layer on the materials surface, and consequently improving the flame retardancy. Based on these results, the possible condensed flame retardant mechanism of TPV/IFR/AHP composites was concluded in detail.     

Effect of a novel phosphorus‐containing compound on the flame retardancy and thermal degradation of intumescent flame retardant polypropylene

A novel flame retardant, tetra(5,5‐dimethyl‐1,3‐ dioxaphosphorinanyl‐2‐oxy) neopentane (DOPNP), was synthesized successfully, and its structure was characterized by FT‐IR, ¹H NMR, and ³¹P NMR. The thermogravimetric analysis (TGA) results demonstrate that DOPNP showed a good char‐forming ability. Its initial decomposition temperature was 236.4°C based on 1% mass loss, and its char residue was 41.2 wt % at 600°C, and 22.9 wt % at 800°C, respectively. The flame retardancy and thermal degradation behavior of novel intumescent flame‐retardant polypropylene (IFR‐PP) composites containing DOPNP were investigated using limiting oxygen index (LOI), UL‐94 test, TGA, cone calorimeter (CONE) test, and scanning electron microscopy (SEM). The results demonstrate that DOPNP effectively raised LOI value of IFR‐PP. When the loading of IFR was 30 wt %, LOI of IFR‐PP reached 31.3%, and it passed UL‐94 V‐0. TGA results show that DOPNP made the thermal decomposition of IFR‐PP take place in advance; reduced the thermal decomposition rate and raised the residual char amount. CONE results show that DOPNP could effectively decrease the heat release rate peak of IFR‐PP. A continuous and compact char layer observed from the SEM further proved the flame retardance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

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

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

Interfacial modification of high impact polystyrene magnesium hydroxide composites effects on flame retardancy properties

High impact polystyrene (HIPS)/magnesium hydroxide (MH) composites were prepared by melt‐blending. Two kinds of interfacial modifiers were used in this research, maleinated poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS‐g‐MA) triblock copolymer and PS. The effects of the use levels of SEBS‐g‐MA on the flame retardancy of HIPS/elastomer/MH based on unmodified and PS‐modified surface were investigated by TEM, FTIR, and combustion tests (horizontal burning test and cone calorimetry). The combustion results showed that comparing composites containing unmodified MH, the flame retarding properties of composites containing PS‐modified MH were obviously improved. The increased performance can be explained that the PS covered on the surface of MH could further improve dispersion of the filler in matrix. Furthermore, there existed a critical thickness of interfacial boundary for optimum flame‐retarding properties in both ternary composites based MH and PS‐modified MH. When the interfacial boundary relative thickness is less than 0.53, the introduction of SEBS‐g‐MA can improve the dispersion degree, leading the improvement of flame retardancy properties. However, with the increase of interfacial boundary thickness, the SEBS‐g‐MA coating around MH acted as a heat and mass transfer barrier, leading to the reduction of flame retardancy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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     

The investigation on the flame retardancy mechanism of nitrogen flame retardant melamine cyanurate in polyamide 6

Melamine cyanurate (MCA) flame retardant polyamide 6 (PA6) shows good flame retardancy, but the corresponding mechanisms have not been completely understood. In this paper, Fourier transform infrared spectra (FTIR), elemental analysis (EA), scanning electronmicroscope (SEM), energy dispersive scanning (EDS), thermogravimeric analysis (TGA) and pyrolysis-gas chromatogram-mass spectrometer (Py-GC-MS) were conducted to investigate the processes including melt-drip phase, gaseous phase and condensed phase of MCA/PA6 system. Compared with original PA6, it is found that MCA flame retardant PA6 mainly undergoes predominant weak bond-breakage degradation forming oligomers rather than oxidative degradation producing low-boiling point fuel as original PA6 does. The produced oligomers can accelerate the formation of the melt drips which effectively removes the combustion heat and latent fuel, also the self-condensation of these oligomers is advantageous to form stable cross-linking structure, thus greatly consolidating the char layer.     

The flame retardant effect of aluminum phosphinate in combination with zinc borate,borophosphate, and nanoclay in polyamide‐6

The effect of zinc borate (ZnB), borophosphate (BPO₄), and organoclay were studied to improve the flame retardancy of polyamide‐6 composites containing organic phosphinates. The flame retardancy of polyamide‐6 composites was investigated using limiting oxygen index (LOI), Underwriters Laboratories (UL‐94) standard, thermogravimetric analysis, Fourier transform infrared spectroscopy, and mass loss calorimeter. The addition of 15 wt% aluminum phosphinate (AlPi) increased the LOI value from 22.5 to 29.5, and V0 rating was obtained from UL‐94 test. The addition of organoclay, ZnB, and borophosphate does not change the predominant gas phase mechanism of AlPi during LOI and UL‐94 tests. The addition of organoclay increased the condensed phase mechanism of AlPi physically by the protective effect of layered silicate, whereas the addition of ZnB increased the condensed phase mechanism of AlPi chemically by the formation of boron aluminum phosphate species deducted from mass loss calorimeter studies. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis,thermal stability,and flame retardancy of PA66, treated with dichlorophenylphsophine derivatives

Synthesis, thermal stability, and flame retardancy of PA66, treated with derivatives of dichlorophenylphosphine, are reported. With an aim to improve the thermal stability and flame retardancy of PA66, along with improving its consistency, several new derivatives of dichlorophenylphosphine, namely bis-(4-carboxyanilino) phenyl phosphamide (BNPO), N-benzoic acid-(ethyl-N-benzoic acid formamide) phosphamide (NENP), poly-N-aniline-phenyl phosphamide (DPPD), and bis-N-benzoguanamine-phenyl phosphamide (MCPO), were synthesized, which resulted in end amino or carboxyl. FTIR, ¹H NMR, MS, and elemental analysis confirmed the chemical structures of the synthesized flame retardants. Interestingly, thermal stabilities and flame retardancies of PA66 improved, however, the intrinsic viscosities ([η]) and viscosity average molecular weights (M_η) decreased with grafting of the flame retardants. Moreover, the consistency was overcome conformingly using SEM without interfacial effect.     

片层状镁铝复合阻燃剂的制备工艺研究

通过共沉淀法合成了片层状镁铝复合阻燃剂,采用正交试验研究了反应温度、反应时间、镁离子起始浓度对层间距及生长机制的影响。结果表明,反应温度为85 ℃,反应时间为1 h,镁离子起始浓度为1.5 mol/L时,得到层间距d（003）达到0.797 89 nm的层状镁铝复合阻燃剂。同时采用透射电镜（TEM）、热重-差热分析（TG-DTA）对最优化产品进行表征。结果显示,产品为片状卷曲结构,分散性好,热分解温度高。     

玻纤增强聚酰胺6/次磷酸钇复合材料的制备及其阻燃性能

以六水合氯化钇(YCl3?6H2O)和次磷酸钠(NaH2PO2)为原料,采用共沉淀法制备了一种新型稀土金属次磷酸盐-次磷酸钇(YHP),对其进行了表征;以YHP为阻燃剂,采用熔融共混法制备了系列玻纤增强聚酰胺6(GFPA)/次磷酸钇复合材料(GFPA/YHP),采用热重、极限氧指数(LOI)、UL-94垂直燃烧和微型量热测试研究了YHP添加量对复合材料热稳定性、阻燃性能及燃烧性能的影响. 结果表明,YHP已成功制备,其具有棒状结构,长度为20?100 ?m,宽度为5?20 ?m,热稳定性很高,降解温度T5%为410℃,最大热失重速率温度Tmax为412℃,750℃下热解的残炭率为90.8wt%. 加入YHP降低了GFPA/YHP复合材料的热分解温度,但提高了其成炭率和高温稳定性,YHP添加量为20wt%时,复合材料的热分解温度为373℃,最大热失重速率温度为414℃,700℃下热解的残炭率为50.42wt%;YHP可有效提高复合材料的阻燃性能,极限氧指数(LOI)达27.5vol%,垂直燃烧级别达UL-94 V-1级;YHP可有效降低复合材料燃烧过程的热释放速率峰值(PHRR)和总放热(THR)量,二者分别降至327 W/g和15.8 kJ/g,比GFPA分别下降了14.1%和25.4%,表明YHP有效降低了GFPA/YHP复合材料燃烧的火灾危险性.     

半芳香聚酰胺热降解性能和非等温结晶动力学研究

在 N2气氛下,用热重分析法研究了半芳香聚酰胺的热降解行为和热降解动力学。并用经 Jeziorny 修正的Arami 方程对其非等温结晶动力学进行了研究。结果表明：半芳香聚酰胺的热降解过程为一步反应,用 Kissinger 方法和Flynn-Wall-Ozawa 方法求得半芳香聚酰胺的热分解活化能分别为258．37 kJ /mol 和227．41 kJ /mol;在非等温条件下,半芳香聚酰胺结晶时可能以片晶形式生长,随着降温速率增大,转变成三维球晶生长。     

Relationship between thermal degradation behavior and flame retardancy on polycarbonate–polydimethylsiloxane block copolymer

This article describes the thermal degradation behavior of polycarbonate–polydimethylsiloxane (PC–PDMS) block copolymer with dimethylsiloxane (DMS) block size 15 to 350 units, and the effects of the PDMS block size and the PDMS content on thermal degradation were studied. PC–PDMS block copolymer with DMS unit of 100 had the lowest value of maximum weight loss rate and the most residue containing silica in the other PC–PDMS block copolymers. The PDMS block size influenced PDMS dispersibility in PC and the moderate PDMS dispersion (? 50 nm) caused high flame retardancy for PC. The control of nanodispersion of PDMS caused the change of thermal degradation behavior and high flame retardancy in PC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1697–1705, 2006     

Thermal degradation analysis of polyamide 6 processed at different cycles using sequential pyrolysis

The principal product from the degradation of polyamide 6 (PA6) is caprolactam, which is a consequence of the intramolecular exchange (cyclization) of PA6. The information obtained from certain thermal analysis techniques, such as differential scanning calorimetry (DSC), is not sufficiently detailed to study the degradation suffered by PA6 in function of these processes, whereas the study of this degradation using other more precise techniques (sequential pyrolysis) and the application of models (Guggenheim and Kezdy‐Jaz‐Bruylants methods) gives us more detailed information on the level of degradation in the many and diverse PA6 analyzed.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

绝缘纸的阻燃改性及其热降解研究

比较了硼酸、磷酸脒基脲两种阻燃剂对绝缘纸热降解过程、剩炭率、击穿电压的影响,结果表明:①阻燃处理的绝缘纸热降解起始温度提前,硼酸提前约20℃,磷酸脒基脲提前约50℃;②硼酸处理的绝缘纸剩炭率升高到18.92%,磷酸脒基脲处理的升高到30.79%;③击穿电压:硼酸维持不变,磷酸脒基脲下降100 kV。同时考察两阻燃剂复配比例对绝缘纸阻燃效果的影响,结果表明,复配阻燃剂中硼酸含量在10%~20%阻燃效果、绝缘性最佳。并通过热重分析方法,对阻燃剂,绝缘纸以及浸渍处理前后绝缘纸的热降解过程进行了比较,从热降解的角度分析阻燃效果的差异。     

Flame retardancy and thermal stability of polyhedral oligomeric silsesquioxane nanocomposites

The flame retardancy and thermal stability of polyhedral oligomeric silsesquioxane (POSS) nanocomposites are reviewed. Results are summarized and compared on the basis of structure–property relationships. Because of the variability of groups attached on POSS, they exhibit different performance in polymer nanocomposites: metal‐containing POSS show good catalytic charring ability; vinyl‐containing and phenyl‐containing POSS promote the strength of char. Improvements in the cone calorimeter (such as reduced peak heat release rate) are advantages of POSS as preceramics for fire retardancy compared with traditional flame retardants, and it will pave the way to the design of inorganic–organic hybrid polymer nanocomposites with enhanced flame retardancy and thermal stability. Copyright © 2011 John Wiley & Sons, Ltd.     

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.     

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

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

含磷共聚酯纤维的阻燃及热降解性能研究

采用含磷反应型阻燃剂、对苯二甲酸和乙二醇共聚,纺丝得到共聚酯纤维,研究了共聚酯纤维的阻燃性能和热降解行为。结果表明,共聚酯纤维含磷质量分数为0．36％,极限氧指数达31．5％,燃烧时无熔滴、烟雾产生。共聚酯起始热分解温度达391℃,热降解温度390～470℃,氮气气氛下的热分解表观活化能为170～200 kJ／mol(分解度为0．15～0．80),且随分解度的增加而增加,其热降解机理比较复杂。