Smoke suppression,flame retardancy,and fire toxicity of polypropylene containing melamine salt of pentaerythritol phosphate halloysite

Polypropylene (PP) was melt blended with a new mono molecular intumescent flame retardant, melamine salt of pentaerythritol phosphate halloysite (MPPH) to enhance its thermal stability, flame retardancy, and smoke suppression properties. The structure of MPPH was elucidated by Fourier transform infrared (FTIR), ¹H NMR, X-ray diffraction (XRD), and energy dispersive X-ray (EDX) analysis. PP composites results showed that MPPH increased the thermal stability of PP at high temperatures in all PP composites. The horizontal flammability test (UL94H) showed that MPPH stopped flame propagation in PP composites. Vertical burning rate test (UL94V) revealed that PP composites can attain V₀ rating at loading levels 25, 30, and 35 wt.% of MPPH. Limiting oxygen index (LOI) data indicated that adding 20, 25, 30, and 35 wt.% of MPPH to PP increased the LOI value of PP (19.2%) to 27.1%, 32.5%, 35.4%, and 38.7%. MPPH succeeded in reducing the maximum specific optical density (Ds_max), mass specific optical density (MOD), and rate of smoke generation during the first 4 min (VOF4) of PP composites compared to PP alone. FTIR gas analyzer results revealed that MPPH decreased the emission of CO and CO₂ in the gas phase during the combustion process. Digital photos and scanning electron microscope (SEM) images of char residues remained after the smoke density test revealed that MPPH succeeded in forming a cellular and cohesive char layer on the PP surface. The new data is expected to increase the use of PP in rigid packaging applications.     

Phosphorus esters of 1-dopyl-1,2-(4-hydroxyphenyl)ethene as effective flame retardants for polymeric materials

1-Dopyl-1,2-(4-hydroxyphenyl)ethene has been converted to phosphorus diesters, 1-dopyl-1,2-(4-diphenylphosphatophenyl)ethene (BDE-DPP), and 1-dopyl-1,2-(4-dopyloxyphenyl)ethene (BDE-DOPO) which have been fully characterized using spectroscopic and thermal methods and assessed as flame retardants in DGEBA epoxy (diglycidyl ether of bisphenol A). Both are effective flame retardants. The ester containing diphenylphosphato groups (BDE-DPP) acts primarily in the condensed phase while that containing only dopyl units acts predominately in the gas phase. DGEBA epoxy containing sufficient 1-dopyl-1,2-(4-dopyloxyphenyl)ethene to provide 2% phosphorus displays a limiting oxygen index of 28, a peak heat release rate of 506 W/g, and a total heat release of 24 kJ/g.     

Ecological issue of polymer flame retardancy

The use of polymer flame retardants has an important role in saving lives. The main flame retardant systems for polymers currently in use are based on halogenated, phosphorous, nitrogen, and inorganic compounds. All of these flame retardant systems basically inhibit or even suppress the combustion process by chemical or physical action in the gas or condensed phase. Conventional flame retardants, such as halogenated, phosphorous, or metallic additives, have a number of negative attributes. An ecological issue of the application of conventional flame retardants demands the search of new polymer flame retardant systems. Among the new trends of flame retardancy are intumescent systems, polymer nanocomposites, preceramic additives, low‐melting glasses, different types of char formers, and polymer morphology modification processing. The brief explanations on the three major types of flame retardant systems (intumescent systems, polymer nanocomposites, and polymer organic char formers) are the subject of this overview. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2449–2462, 2002     

A monomolecular organophosphate for enhancing the flame retardancy,thermostability and crystallization properties of polylactic acid

Polylactic acid (PLA) is regarded as one of the most promising bioplastics. However, its inherent high flammability of PLA seriously limits its application in the emerging fields. Although the traditional phosphate flame retardants showed excellent flame retardant efficiency in PLA, they often failed to meet the processing requirements of PLA and the thermal stability of PLA composites was decreased after their addition. Herein, an organophosphate flame retardant pentaerythritol bis(phenyl phosphonate) (PBPP) with high thermal stability and phosphorus content was synthesized by the nucleophilic substitution reaction in our laboratory. The introduction of PBPP simultaneously improved the flame retardancy, thermostability and crystallization properties of PLA. Only 3 wt% PBPP endowed PLA composites with UL-94 V-0 grade and higher LOI of 28.3% due to its excellent gas phase effect. Moreover, the crystallinity of PLA/PBPP4 was enhanced from 14.2% of PLA to 32.2% with the improvement of 127%. Because of the similar structure and good compatibility between organophosphate flame retardant and PLA matrix, flame retardant PLA/PBPP maintained almost the same strength as neat PLA. This study provided a novel way for the preparation of a high-performance flame retardant PLA composites with excellent comprehensive properties and it was important to expand the application value of multifunctional PLA materials.     

Flame-retardant compounds for polymeric materials from an abundantly available,renewable biosource,castor oil

Castor oil is a triglyceride extracted from the seed (castor bean) of the castor plant. This plant will thrive on relatively poor soil and in an arid climate. The oil is nonedible but is produced annually in large volume to be converted to biodiesel (largely for the European market). The oil contains both unsaturation and hydroxyl functionality that may be utilized for conversion to flame retarding materials. A series of phosphorus esters has been generated from castor oil. All display good flame retardancy in the diglycidyl ether of bisphenol A (DGEBA) epoxy resin. Introduction of bromine at the double bond generally enhances the flame retardancy of these esters.     

Recent developments in the fire retardancy of polymeric materials

The widespread applications of polymeric materials require the use of conventional flame retardants based on halogen and phosphorous compounds to satisfy fire safety regulatory standards. However, these compounds, particularly halogen-based examples, are persistent organic pollutants of global concern and generate corrosive/toxic combustion products. To account for eco-friendliness, ultimate mechanical/physical properties and processing difficulties, the window of options has become too narrow. Although the incorporation of non-toxic nanofillers in polymers shows positive potential towards flame retardancy, many obstacles remain. Moreover, most of the literature on these materials is qualitative, and often points to conflicting/misleading suggestions from the perspectives of short-term and long-term fire exposure tests. Hence, there is a renewed need to fundamentally understand the fire response of such materials, and complement experimental results with theoretical modelling and/or numerical simulation.     

硼酸锌的性质、制备及阻燃应用

硼酸锌是最早的无机阻燃剂之一,具有热稳定性好、毒性低和消烟等良好的特点。综述了硼酸锌的主要性质、制备工艺和阻燃机理,同时也对硼酸锌与其他无机阻燃剂的复配效应和硼酸锌在各个领域中的应用进行了阐述。重点介绍了3大类制备硼酸锌的方法：传统的制备工艺由于原料价格较高或后处理工序复杂而存在弊端;超细硼酸锌的制备对硼酸锌的粒径要求比较高,但是由于其性能比较好,是目前研究的主要对象;固相法制备硼酸锌的研究,国外比国内进行得早,也较成熟一点,并指出通过高温烧结得到的硼酸锌是一种含有几种不同结构硼酸锌的混合物。最后指出了制备晶须状硼酸锌的意义。     

Dynamics of intumescence of fire-retardant polymeric materials

A new numerical method allowing one to estimate a temperature field in an intumescent fire-retardant coating is proposed. The data on heat conductivity of the material, on kinetics of its decomposition, and on kinetics of change of its rheological properties serve for calculation of input parameters. On the basis of experimental information about curing kinetics, the algorithm computes a viscosity of the material in each elementary layer of the coating. It is assumed that the local change of viscosity, in turn, predetermines a local expansion coefficient of the coating. The results of the calculations are compared with the experimental data obtained for the coating on the basis of phenol–formaldehyde resin and boron oxide. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1523–1542, 1998     

聚合物材料阻燃性能试验方法相关性研究进展

介绍了聚合物材料阻燃性能常用的评价方法,如氧指数法,UL94法,锥型量热计法等,概述了每一种测试方法的优缺点,以及这些试验方法之间或与其他燃烧性能试验方法之间的相关性。     

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。     

Synergistic effects of aluminum hydroxide,red phosphorus,and expandable graphite on the flame retardancy and thermal stability of polyethylene

The flame-retardant low-density polyethylene (LDPE) composites loading aluminum hydroxide (ATH), red phosphorus (RP), and expandable graphite (EG) were successfully prepared. The flame retardancy, the thermo-oxidative stability, and the mechanical property of the composites were investigated. The synergistic effect of ATH, RP, and EG on the flame-retardant property and thermal behavior of LDPE were observed. The limiting oxygen index value of LDPE significantly increased from 17.1% to 25.4% upon the incorporation of 15 wt.% of the mixture of three fillers with ATH:RP:EG mass ratio of 1:1:1; and this composite achieved the V-0 classification of the UL94 vertical burning test. The thermogravimetric analysis of this composite under air atmosphere revealed that its residue weight remained 27.89% at 900°C. Furthermore, the results of tension tests indicated that the surface modification of ATH by magnesium stearate and RP by poly(methylhydrosiloxane) noticeably improved the tensile strength and the elongation of the composite.     

膨胀型阻燃剂及其在塑料中的应用研究进展

介绍了膨胀型阻燃剂（IFR）的组成、阻燃机理、种类及以及处理技术,概述了膨胀型阻燃剂在塑料中的应用研究进展,指出了其今后的发展趋势。     

高分子材料阻燃与抑烟的分立设计思想

随着高分子材料在人类生产生活中的广泛应用,其防火安全性问题日益凸显,高效环保阻燃抑烟剂的开发成为当前材料领域亟待解决的问题之一。然而,与发展较为成熟的阻燃剂研究领域相比,世界各国在抑烟剂方面的研究普遍处于起步和初期发展阶段。同时,多数抑烟剂的研究处于阻燃剂的从属地位,即在阻燃剂的基础上附加抑烟的性能,对单功能抑烟剂的开发重视度不够,限制了其进一步的发展。高分子材料中结构和官能团的多样性使其燃烧和发烟机理有显著不同,因此针对不同种类的高分子材料的燃烧和发烟过程,其阻燃和抑烟剂在组成和结构上的设计亦应有明显区别。以同一种材料实现阻燃和抑烟的兼顾,往往顾此失彼,导致两者性能均无法得到最大的发挥。因此,本文提出将阻燃剂和抑烟剂的功能分离开来的设计思想,加强单功能抑烟剂的研究投入,对阻燃/抑烟材料的化学组成和结构分别进行有针对性的设计,再进行功能优化复配,将是实现高分子材料高效阻燃抑烟的有效途径之一。     

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.     

高效阻燃剂聚磷酸铵的合成工艺研究

以磷酸和尿素为原料合成了高聚合度的聚磷酸铵。通过单因素实验对制备工艺进行了优化,考察了原料配比、升温速率、预聚合温度、固化温度和固化时间等对产品质量的影响,采用核磁共振法（NMR）测定了聚磷酸铵的平均聚合度,并用X射线衍射(XRD )和红外(IR)相结合的方法对产品的晶体结构进行了表征,同时测定了聚磷酸铵的溶解度和总磷含量。结果表明,最佳制备工艺条件为：n（磷酸)∶n（尿素）=1∶1.9,预聚合阶段升温速率为2～3 ℃/min,预聚合温度为130 ℃,固化温度为230 ℃,固化时间为90 min。此条件下合成的聚磷酸铵平均聚合度为114,水中溶解度为0.492 g,总磷质量分数为31.75%,XRD表征结果表明,所得产品为Ⅰ型聚磷酸铵。     

活性阻燃技术在环氧树脂上的应用

综述了近年来国内外活性阻燃技术在环氧树脂上研究应用的热点,主要包括溴、磷、氮、硅系阻燃剂的研究与应用。     

国内溴化聚苯乙烯阻燃剂合成技术进展

针对提高产品质量,降低成本,提高生产效率,从工艺和设备方面综述了国内溴化聚苯乙烯阻燃剂合成技术进展。     

Preparation of multifunctional silicon-phosphorus acrylate particles for the simultaneous improvement of the flame retardancy and mechanical performance of polylactic acid

Polylactic acid (PLA) is a biodegradable plastic that currently has limited application owing to its poor fire resistance and brittleness. Herein, a multifunctional silicon-phosphorus acrylic resin(P/Si-ACR) is designed to endow both flame retardancy and toughness to PLA. P/Si-ACR is prepared by seeded emulsion polymerization with polysiloxane as the core layer and diethyl methylphosphonate acrylate and 9, 10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide acrylate as the shell materials. P/Si-ACR has a particle size of approximately 200 nm and glass transition temperatures of −38 and 152°C for the core and shell layers, respectively. Addition of 7 wt% P/Si-ACR to PLA increases the notched impact strength and elongation at break by 124% and 46%, respectively. This improved mechanical performance is due to the elasticity of silicone rubber and the promotion of crystallization by P/Si-ACR. Combustion testing revealed that the limiting oxygen index increases from 19.1% to 22.5%, while the peak heat release rate decreases by 36%. This enhanced flame retardancy is due to the synergistic effect of phosphorus and silicon, with the former promoting graphitization and inhibiting the free radical degradation of PLA, and the latter stabilizing the char residue. Therefore, P/Si-ACR is a promising multifunctional modifier that can achieve an optimal balance among flame retardancy, crystallization performance, and toughness in polymers.     

新型含磷阻燃剂的制备及性能

以双三羟甲基丙烷为原料合成一种新型含磷阻燃剂,该阻燃剂分子量较大,具有稳定的环状结构,热稳定性高于常用阻燃剂,阻燃效果好。探讨了原料配比、反应温度、反应时间对产率的影响,考察了目标产物的热稳定性能及其对不同织物的阻燃效果,用傅里叶变换红外光谱仪表征了中间体及目标产物的结构。结果表明,当原料配比为1∶3时,磷化温度为50℃,磷化时间5h,胺化温度为75℃时,反应效果较好,收率可达90%以上。目标产物对于锦纶的阻燃效果比较明显,对涤纶、棉有一定的阻燃效果,对于混纺、腈纶阻燃效果不明显。     

Preparation of novel biomass humate flame retardants and their flame retardancy in epoxy resin

Humic acid (HA), a biomass material with plentiful oxygen-containing functional groups, showed huge potential to be considered as a promising charring agent in flame retardancy. In this study, this HA was modified with four different metal ions like Fe²⁺, Mn²⁺, Al³⁺, and Cu²⁺ and finally, introduced into the epoxy resin (EP) to enhance the flame retardancy of the EP and the dispersion of these flame retardants into the EP matrix. When 10 wt% of HA-Fe and HA-Mn were incorporated into EP matrix, the limiting oxygen index (LOI) was increased from 21.2% for EP to 26.6 and 25.3% for the EP composites and the peak heat release rate (pHRR) was reduced by 36 and 35.5%, respectively. Such a significant improvement in flame retardancy was attributed to the catalytic charring of HA in the presence of metal ions, which ultimately increased the residual char formation and produced compact char layers during the combustion process to retard the transfer of heat and combustible gases between the EP composites and the flame zone. Finally, this kind of application provided a feasible way for the development of an environmentally friendly flame retardant with high efficiency, which improved the fire safety of EP matrix.