Effect of fire retardants on fire-resistance and adhesion properties of epoxy urethane compositions

The results of investigating the effects of various fire retardants on the fire-resistance of epoxy urethane compositions are presented. It is shown that the simultaneous presence of phosphorus and bromine, as well as oxides and hydroxides, favors efficient coke formation and a reduction in combustibility while retaining the physicomechanical characteristics of an epoxy urethane adhesive.     

Development of additives possessing both solid-phase and gas-phase flame retardant activities

Effective additives are required to impart a measure of fire retardancy to polymeric materials used in a variety of applications. Traditionally, these have been gas-phase active additives, most commonly organohalogen compounds or solid-phase active agents, often organophosphorus compounds. Organosphosphorus flame retardants are often very effective but may suffer from a cost disadvantage when compared with their organobromine counterparts. Organohalogen flame retardants are usually quite effective but their use is a subject to several environmental concerns. The development of additives that could simultaneously promote both types of fire retardant action could make available flame retardants that are both more cost effective and more environmentally friendly than those currently in use. Several sets of compounds with the potential to display both solid-phase and gas-phase flame retardant activities have been prepared and evaluated.     

阻燃聚丙烯共混体系结晶形态研究

本工作利用WAXD、DSC、PLM、PCM和SAIS等手段,对几种具有代表性的阻燃PP共混体系的结晶形态和结晶行为进行了研究。结果表明各种阻燃剂存在,对阻燃PP体系中PP的结晶形态和结晶行为有明显影响。其影响情况取决于这些阻燃剂自身的各种特性。另外,PP的结晶对某些阻燃剂的分散也有一定的影响,其结晶过程是体系中阻燃剂的一个再分散过程。     

Thermal properties of compounds possessing both solid-phase and gas-phase flame retardant potential

Effective additives are required to impart a measure of fire retardancy to polymeric materials used in a variety of applications. Traditionally, these have been gas-phase active additives, most commonly organohalogen compounds, or solid-phase active agents, often organophosphorus compounds. Organosphosphorus flame retardants are often very effective but may suffer from a cost disadvantage when compared with their organobromine counterparts. Organohalogen flame retardants are usually quite effective but their use is subject to several environmental concerns. The development of additives that could simultaneously promote both types of fire retardant action could make available flame retardants that are both more cost effective and more environmentally friendly than those currently in use. Several sets of compounds including bromoanilino triazine derivatives and bromoaryl phosphates with the potential to display both solid-phase and gas-phase flame retardant activity have been prepared and evaluated by a variety of thermal methods.     

A review of candidate fire retardants for polyisoprene

Polyisoprene elastomer, as natural rubber (NR) or manufactured synthetically (IR), is used in rubber compounds for applications such as tyres, dampers and suspension elements. NR/IR compounds without fire retardants have a low resistance to burning, and emit large quantities of dense smoke. This is because polyisoprene readily decomposes upon heating, by random chain scission, vaporising into a mixture of small aromatic chemical species, which ignite readily and form smoke particles with negligible char residue formation. The effects of commonly used additives on the thermal decomposition and burning of polyisoprene are reviewed; whilst cross-linking agents have significant effects on physical and ageing properties, they have little effect on thermal decomposition and burning. Fillers such as carbon black and silicas reduce the fuel content by dilution of the polymer and the formation of a stabilising residue.Potential approaches for fire retarding IR are reviewed, identifying two main approaches; halogenated additives, or high loadings of aluminium hydroxide (ATH), neither of which are satisfactory. Other potential approaches are identified, including the use of phosphorus and nitrogen based additives as intumescent char formers, and with zeolites as char catalysts. Alternative inorganic fire retardants to ATH are identified for use, and zinc hydroxystannate and zinc borate are considered as synergists with ATH. Expandable graphite (EG) is identified for use in other elastomers and has potential for polyisoprene. Nano-scale fire retardants such as montmorillonite clay and multi-walled carbon nanotubes are reported typically as a secondary additive to hydrated fillers, but have yet to make a successful transition to industrial processing.     

Effect of halogenless flame retardants on the thermal properties, flammability, and fire hazard of cross-linked EVM/NBR rubber blends

This paper presents the results of investigating the thermal stability, flammability, and fire hazard of cross-linked EVM/NBR blends unfilled and filled with halogenless flame-retardant compounds such as melamine cyanurate or magnesium hydroxide. The thermal analysis of the blends was carried out in the atmosphere of air. The activation energy of the composite destruction was determined by two non-isothermal methods: Flynn–Wall–Ozawa’s and Kissinger’s methods. The flammability of the composites obtained was determined by the method of oxygen index and on the basis of their combustion in air. The fire hazard of the vulcanizates investigated was determined with the use of a cone calorimeter and on the basis of toxicometric parameters W _LC50SM. The test results have shown that the flame retardants used increase the thermal stability of the cross-linked blends and decrease their flammability, and thereby allow one to obtain self-extinguishing or non-flammable polymeric materials. The cross-linked EVM/NBR blends filled with these flame-retardant compounds are characterized by good mechanical properties and reduced fire hazard.     

A review on flammability of epoxy polymer,cellulosic and non‐cellulosic fiber reinforced epoxy composites

Natural fiber is well‐known reinforcement filler in polymer‐matrix composites. Composite components like organic polymers and natural fibers are natural fire conductors as the natural fiber consists of cellulose, hemicellulose, and lignin, and hence are as highly flammable as wood. Natural fiber reinforced composite materials are progressively being used in a variety of applications where their fire response is a hazardous consideration, for example, in the automotive (transportation) and building‐construction industries. As a result, an awareness of their performance or response during a fire and the use of conventional fire retardants are of great importance, as they are subject to thermal decomposition when exposed to intensive high heat or fire sources. In this review paper, fire flammability is the main concern for cellulosic and non‐cellulosic fiber‐reinforced polymer composites, especially epoxy composites. This paper reviews the literature on the recent developments in flammability studies concerning polymers, epoxy polymers, cellulosic‐fibers, and non‐cellulosic fiber‐reinforced epoxy bio‐composites. The prime objective of this review is to expand the reach of “fire retardants for polymer materials and composites” to the science community, including physicists, chemists, and engineers in order to broaden the range of their applications. Copyright © 2015 John Wiley & Sons, Ltd.     

阻燃剂对5Ah锂离子软包电池倍率性能和安全性能的影响研究

在电解液中加入不同含量(5 %,10 %,20 %)的阻燃剂,研究了其对LiNi _0.4Co_0.2Mn_0.4 O₂三元材料作为正极材料组装的5 Ah锂离子软包电池的倍率性能、过充性能和短路性能的影响. 实验结果表明,电解液中5 %体积含量的阻燃剂使软包电池在1C和2C放电时,具有最好的倍率性能;当阻燃剂的体积含量提升到20 %,在过充时,电池表面温度升高的最少;在短路实验时,电池不起火、不爆炸.     

Flame-retarding vinyl polymers using phosphorus-functionalized styrene monomers

Organohalogen compounds, principally brominated aromatics, continue to be the largest selling flame retardants worldwide. However, there is increasing concern about the bioaccumulation and potential toxicity of these compounds. Consequently, there is great interest in the development of effective alternatives to these materials. Organophosphorus compounds seem to offer the most promise as replacements for halogen-containing flame retardants. One approach to flame-retarding vinyl polymers is to develop reactive monomers containing high levels of phosphorus which may be incorporated directly into the polymer structure. Five phosphorus monomers for use in making fire-retardant copolymers with styrene have been synthesized. A comparative study of the thermal stability of the copolymers has been conducted. Preliminary potential fire behavior data have been obtained using pyrolysis combustion flow calorimetry.     

Chemical and physical properties of foamed cokes and their effect on inflammability

By means of IR and Raman spectroscopy chemical and physical properties of foamed cokes, formed during combustion and pyrolysis of PP based compositions, containing intumescent fire retardants (IFR) were investigated. It was established that thermal conductivity coefficients of coke material lie in the range of 0.12–0.32 W/m/K and are weakly dependent on the initial composition of IFR. It was shown that the effectiveness of IFR is mainly determined by the internal microstructure of the foamed cokes and the kinetic parameters of their formation.     

Influence of fire retardants on the combustibility of decorative resins based on butadiene-styrene and butadiene rubber combination

The results of investigations of the influence of fire retardants on the combustibility and elastic-strength properties of light-colored resins based on a combination of butadiene-styrene and butadiene rubber are presented. The amounts of fire retardants required for production of decorative self-extinguishing resin of light color based on a combination of butadiene-styrene and butadiene rubber were established. The influence of the ratio of rubbers on the temperature limit of brittleness of the self-extinguishing resin samples was studied.     

绿色环保型氢氧化镁阻燃剂

介绍了阻燃剂的种类和发展趋势,并重点介绍了氢氧化镁阻燃剂的阻燃机理、特点、应用和发展。指出氢氧化镁阻燃剂是一种新型的、对环境友好的无机阻燃剂。     

Molecular Firefighting—How Modern Phosphorus Chemistry Can Help Solve the Challenge of Flame Retardancy

The ubiquity of polymeric materials in daily life comes with an increased fire risk, and sustained research into efficient flame retardants is key to ensuring the safety of the populace and material goods from accidental fires. Phosphorus, a versatile and effective element for use in flame retardants, has the potential to supersede the halogenated variants that are still widely used today: current formulations employ a variety of modes of action and methods of implementation, as additives or as reactants, to solve the task of developing flame‐retarding polymeric materials. Phosphorus‐based flame retardants can act in both the gas and condensed phase during a fire. This Review investigates how current phosphorus chemistry helps in reducing the flammability of polymers, and addresses the future of sustainable, efficient, and safe phosphorus‐based flame‐retardants from renewable sources.     

Polypropylene fabrics padded with microencapsulated ammonium phosphate: Effect of the shell structure on the thermal stability and fire performance

Three types of microcapsules of di-ammonium hydrogen phosphate (DAHP) with different polymeric shells were evaluated as flame retardants in commercial polyurea padding for textiles. Encapsulated FR agent has the advantage of being compatible with the polymer matrix. The thermal degradation for the three types of DAHP microcapsules shows that our microcapsules act as intumescent fire retardants. The reaction to fire of polypropylene fabrics padded with FR polyurea loaded with neat DAHP or microencapsulated DAHP was studied with the cone calorimeter as a fire model.     

阻燃剂及材料的阻燃处理

阻燃剂是能够保护材料不着火或使火焰难以蔓延的化学物质。介绍了常见阻燃剂的种类、阻燃机理、材料的阻燃处理及新型阻燃剂的发展,以增强人们对阻燃技术领域的认识和了解。     

Fire retardant action of mineral fillers

Endothermically decomposing mineral fillers, such as aluminium or magnesium hydroxide, magnesium carbonate, or mixed magnesium/calcium carbonates and hydroxides, such as naturally occurring mixtures of huntite and hydromagnesite are in heavy demand as sustainable, environmentally benign fire retardants. They are more difficult to deploy than the halogenated flame retardants they are replacing, as their modes of action are more complex, and are not equally effective in different polymers. In addition to their presence (at levels up to 70%), reducing the flammable content of the material, they have three quantifiable fire retardant effects: heat absorption through endothermic decomposition; increased heat capacity of the polymer residue; increased heat capacity of the gas phase through the presence of water or carbon dioxide. These three contributions have been quantified for eight of the most common fire retardant mineral fillers, and the effects on standard fire tests such as the LOI, UL 94 and cone calorimeter discussed. By quantifying these estimable contributions, more subtle effects, which they might otherwise mask, may be identified.     

Fire retardant synergism between melamine and triphenyl phosphate in poly(butylene terephthalate)

The fire retardant efficiency of melamine (MA) and triphenyl phosphate (TPP) in poly(butylene terephthalate) (PBT) was studied by the limiting oxygen index (LOI) and the UL94 test. On adding 10 wt. % MA and 20 wt. % TPP, LOI increased from 20.9 to 26.6 and the UL94 V-0 rating was achieved. SEM and DSC analyses show that the fire retardants are compatible with PBT and facilitate crystallization of PBT. The occurrence of an interaction between MA + TPP and PBT was elucidated by TGA, dynamic FTIR, and pyrolysis/GC/MS. MA + TPP changes the degradation path of PBT and modifies the compositions of the gas and condensed-phase products.     

Characterization of fire retardant polymer blends by temperature resolved in-source pyrolysis mass spectrometry

The characterization of fire retardant polymer blends by temperature resolved in-source pyrolysis mass spectrometry (PYMS) is demonstrated with a few examples. Electron impact (EI) and electron capture negative ionization (ECNI) were used to identify the thermal degradation products of polymer blends containing brominated fire retardants. PYMS (EI mode) offers an analytical instrument for a fast analysis of unknown mixtures of polymers and for the presence of fire retardant additives. Under electron impact conditions, in vacuo, low-molecular weight additives like fire retardants mainly evaporate from the polymer matrix. PYMS (EI mode) has been used for the characterization of addition polymers like polystyrene and acrylonitrile-butadiene-styrene copolymer, and for condensation polymers like the polyester poly(butylene terephthalate). Applying electron capture negative ionization, at low argon pressure in the ionization chamber, a more realistic pyrolysis situation is created because the premature loss of volatile additives is suppressed. The selectivity of ECNI for electron accepting groups like bromine makes it possible to study the influence of brominated compounds on the degradation processes in the melt. This is demonstrated by our studies on polystyrene and acrylonitrile-butadiene-styrene copolymer. High-molecular weight pyrolysis products in the m/z range of 1000 - 2000 are detected for p-bromopolystyrene and for a blend of high impact polystyrene with the fire retardant system decabromodiphenyl ether/antimony(III) oxide. In addition to the formation of antimony bromides shown in earlier studies, the emission of the synergist antimony(III) oxide as a dimeric cluster (Sb₄O₆) or as a reduced Sb₄ cluster is observed under PYMS conditions.     

Synthesis and characterization of a fire-retardant polyester: Copolymers of ethylene terephthalate and 2-carboxyethyl(phenylphosphinic) acid

This article describes the synthesis and characterization of a polymer-bound nonhalogen fire retardant (NHFR). The reactive fire retardant used in this study is 2-carboxyethyl(phenylphosphinic) acid (CEPP); the polymer is poly(ethylene terephthalate) (PET). Fire-retardant and other modifiers of polymer properties must be bound to the polymer for use in fiber, medical, and food contact applications. Copolymers containing very high levels of CEPP have been prepared. Although fire retardancy in PET is achieved at relatively low levels of CEPP, our ability to produce copolymers with high levels of phosphorous makes them very attractive as polymeric nonfugitive fire retardants for other polymers, such as polycarbonate, nylon, acrylonitrile–butadiene–styrene (ABS), poly(butylene terephthalate) (PBT), and various polymer blends. This article also describes NHFR polyester compositions containing 4,4′-biphenyl dicarboxylic acid and CEPP. It is shown that an increase in aromaticity gained by incorporating the 4,4′-biphenyl dicarboxylic acid leads to higher limiting oxygen index values. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3119–3128, 1999     

Recent Progress in Two-dimensional Nanomaterials Following Graphene for Improving Fire Safety of Polymer (Nano)composites

The high fire safety of polymer nanocomposites is being pursued by research institutions around the world. In addition to intrinsic flame retardancy strategy, the additive-type flame retardants have attracted increasing attention due to low commercial cost and easy fabrication craft. However, traditional additive-type flame retardants usually need high addition amount to achieve a desirable effect, which causes many side-effects on the overall performance of polymer materials, such as deteriorated mechanical property and processability. At present, two-dimensional(2 D) nanomaterials have also been applied to reduce the fire hazards of polymer(nano)composites with the coupling of barrier function and catalysis as well as carbonization effect. Even though most research work mainly focus on graphene-based flame retardants, more emerging two-dimensional nanomaterials are taking away research attention, due to their complementary and unique properties, mainly including hexagonal boron nitride(h-BN), molybdenum disulfide(MoS_2), metal organic frameworks(MOF), carbon nitride(CN),titanium carbide(MXene) and black phosphorene(BP). In this review, except for graphene, the flame retardant mechanism involving different layered nanomaterials are also reviewed. Meanwhile, the functionalization method and flame retardancy effect of different layered nanomaterials are emphatically discussed for offering an effective reference to solve the fire hazards of polymer materials. Moreover, this work objectively evaluates the practical significance of polymer/layered nanomaterials composites for industrial application.