Flame retardant epoxy resins based on diglycidyloxymethylphenylsilane

Silicon‐containing epoxy resins were prepared from diglycidyloxymethylphenyl silane (DGMPS) and diglycidylether of bisphenol A (DGEBA) by crosslinking with 4,4′‐diaminodiphenylmethane (DDM). Several DGMPS/DGEBA molar ratios were used to obtain materials with different silicon contents. Their thermal, dynamomechanical, and flame‐retardant properties were evaluated and related to the silicon content. The weight loss rate of the silicon‐containing resins is lower than that of the silicon free resin. Char yields under nitrogen and air atmospheres increase with the silicon content. The LOI (limited oxygen index) values increased from 24 for a standard commercial resin to 36 for silicon‐containing resins, demonstrating improved flame retardancy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5580–5587, 2006     

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.     

Chlorine-Functional Silsesquioxanes (POSS-Cl) as Effective Flame Retardants and Reinforcing Additives for Rigid Polyurethane Foams

The subject of the research was the production of silsesquioxane modified rigid polyurethane (PUR) foams (POSS-Cl) with chlorine functional groups (chlorobenzyl, chloropropyl, chlorobenzylethyl) characterized by reduced flammability. The foams were prepared in a one-step additive polymerization reaction of isocyanates with polyols, and the POSS modifier was added to the reaction system in an amount of 2 wt.% polyol. The influence of POSS was analyzed by performing a series of tests, such as determination of the kinetics of foam growth, determination of apparent density, and structure analysis. Compressive strength, three-point bending strength, hardness, and shape stability at reduced and elevated temperatures were tested, and the hydrophobicity of the surface was determined. The most important measurement was the determination of the thermal stability (TGA) and the flammability of the modified systems using a cone calorimeter. The obtained results, after comparing with the results for unmodified foam, showed a large influence of POSS modifiers on the functional properties, especially thermal and fire-retardant, of the obtained PUR-POSS-Cl systems.     

添加型磷腈类阻燃剂在高分子材料中的应用

添加型磷腈类阻燃剂具有热稳定性好、耐候性好、低烟、低毒、低添加量和吸潮性低等优点,在阻燃高分子材料领域得到广泛应用。综述了近些年来国内外添加型磷腈类阻燃剂在高分子材料中的应用研究进展,分析了磷腈阻燃剂阻燃高分子材料的研究现状,为新型磷腈类阻燃剂的研发提供参考。     

Flame retardancy of fibre-reinforced epoxy resin composites for aerospace applications

The applicability of phosphorus-containing reactive amine, which can be used in epoxy resins both as crosslinking agent and as flame retardant, was compared in an aliphatic and an aromatic epoxy resin system. In order to fulfil the strong requirements on mechanical properties of the aircraft and aerospace applications, where they are mostly supposed to be applied, carbon fibre-reinforced composites were prepared. The flame retardant performance was characterized by relevant tests and mass loss type cone calorimeter. Besides the flame retardancy, the tensile and bending characteristics and interlaminar shear strength were evaluated. The intumescence-hindering effect of the fibre reinforcement was overcome by forming a multilayer composite, consisting of reference composite core and intumescent epoxy resin coating layer, which proved to provide simultaneous amelioration of flame retardancy and mechanical properties of epoxy resins.     

Flame retardant polystyrene copolymers: preparation,thermal properties,and fire toxicities

A new phosphorous‐ and nitrogen‐containing reactive monomer, DMPMA, was first synthesized by nucleophilic substitution reaction of 2‐(6‐oxido‐6H‐dibenz[c,e][1,2]oxaphos‐phorin‐6‐yl) methanol, N‐hydroxymethyl acrylamide and methyldichlorophosphate. The copolymer of styrene (St) and DMPMA (poly(St‐co‐DMPMA)) was prepared and then characterized by Fourier transform infrared, differential scanning calorimetry, thermogravimetric analysis (TGA), microscale combustion calorimeter and steady‐state tube furnace (SSTF). The results proved that poly(St‐co‐DMPMA) was well synthesized, while the glass transition temperature of the copolymer was decreased with increasing DMPMA content. The TGA results showed that the initial degradation temperature of poly(St‐co‐DMPMA) decreased, but its char yield and decomposition temperature improved compared to that of pure polystyrene. After incorporating DMPMA, the fire performance of the copolymer was significantly improved. The results obtained from the SSTF indicated that the carbon monoxide and smoke yield density were increased due to the incomplete combustion of the copolymer. Copyright © 2014 John Wiley & Sons, Ltd.     

气相色谱火焰光度法测定水体中9种有机磷酸酯阻燃剂

建立了水体中9种有机磷酸酯阻燃剂(OPFRs)的液液萃取(LLE)/气相色谱-火焰光度(GC-FPD)测定方法。对比研究了液液萃取、固相萃取条件和仪器测定条件。最终选择液液萃取作为样品的提取方法,以二氯甲烷为提取溶剂;有机磷专用柱Rtx-OPPesticides 2作为分析柱,15 min内可实现待测组分的良好分离。在优化条件下,9种OPFRs在1.0~500 ng/m L范围内呈良好的线性关系(r2≥0.998),方法检出限为1.0~2.0 ng/L。在5,100,300 ng/L加标水平下,9种OPFRs空白水样的加标回收率为75.9%~111%;相对标准偏差(RSD)为3.3%~15%。该方法应用于6个实际湖泊地表水样品的检测,OPFRs的检出率为100%,其组分检出总浓度为408~1 532 ng/L,可见湖泊地表水中存在明显的OPFRs污染。     

Flame retardant properties and mechanism of an efficient intumescent flame retardant PLA composites

The charring agent (CNCA‐DA) containing triazine and benzene rings was combined with ammonium polyphosphate (APP) to form intumescent flame retardant (IFR), and it was occupied to modify polylactide (PLA). The flame retardant properties and mechanism of flame retardant PLA composites were investigated by the limited oxygen index (LOI), vertical burning test (UL‐94), thermogravimetric analysis, microscale combustion calorimetry, scanning electron microscopy, laser Raman spectroscopy analysis and X‐ray photoelectron spectroscopy. The analysis from LOI and UL‐94 presented that the IFR was very effective in flame retardancy of PLA. When the weight ratio of APP to CNCA‐DA was 3:1, and the IFR loading was 30%, the IFR showed the best effect, and the LOI value reached 45.6%. It was found that when 20 wt% IFR was loaded, the flame retardancy of PLA/IFR still passed UL‐94 V‐0 rating, and its LOI value reached 32.8%. The microscale combustion calorimetry results showed that PLA/IFR had lower heat release rate, total heat release, and heat release capacity than other composites, and there was an obvious synergistic effect between APP and CNCA‐DA for PLA. IFR containing APP/CNCA‐DA had good thermal stability and char‐forming ability with the char residue 29.3% at 800°C under N₂ atmosphere. Scanning electron microscopy observation further indicated that IFR could promote forming continuous and compact intumescent char layer. The laser Raman spectroscopy analysis and X‐ray photoelectron spectroscopy analysis results indicated that an appropriate graphitization degree of the residue char was formed, and more O and N were remained to form more cross‐linking structure. Copyright © 2016 John Wiley & Sons, Ltd.     

Phosphorylated cellulose/Fe3+ complex: A novel flame retardant for epoxy resins

A novel flame retardant containing cellulose, phosphorus and ferrum complex (Cell‐P‐Fe) was successfully synthesized and then it was used as flame retardants in epoxy resins (EP). Due to the present of acid sources and carbon sources, the Cell‐P‐Fe exhibits improved thermal stability and flame retardant properties. The EP/Cell‐P‐Fe composites with 10 wt% of Cell‐P‐Fe show remarkably improved LOI and UL‐94 values compared with the flame retardants without ferrum. At the loading of 10.0 wt% flame retardants, the char yield for EP/Cell‐P‐Fe composites increased to 29.1 wt%, indicating the improved thermal stability at high temperature. Moreover, thermogravimetric analysis, morphology of char residues and FTIR results demonstrate that stable char layers are formed on the surface of the composites during the combustion, attributing to the catalytic carbonization effect of Fe and phosphorus and the present of cellulose as carbon source. The stable char layers, which can protect the underlying materials from heat and oxygen, play an important role in the flame retardancy enhancement.     

Flame retardancy and thermal degradation of intumescent flame retardant polypropylene material

The flame retardancy and thermal degradation properties of polypropylene (PP) containing intumescent flame retardant additives, i.e. melamine pyrophosphate (MPyP) and charring‐foaming agent (CFA) were characterized by limiting oxygen index (LOI), UL 94, cone calorimeter, microscale combustion calorimetry, and thermogravimetric analysis (TGA). It has been found that the PP material containing only MPyP does not show good flame retardancy even at 30% additive level. Compared with the PP/MPyP binary system, the LOI values of the PP/MPyP/CFA ternary materials at the same additive loading are all increased, and UL 94 rating is raised to V‐0 from no rating (PP/MPyP). The cone calorimeter results show that the heat release rate and mass loss rate of some ternary materials decrease in comparison with the binary material. The microscale combustion calorimetry results indicate that the sample containing 22.5 wt% MPyP and 7.5 wt% CFA has the lowest heat release rate among all samples. The TGA results show that the thermal stability of the materials increases with the addition of MPyP, while decreases with the addition of CFA. Copyright © 2009 John Wiley & Sons, Ltd.     

磷系阻燃共聚酯的结构与性能

采用磷系阻燃剂2-羧乙基苯基次磷酸（CEPPA）作为第3单体,通过聚合反应制备了含磷的阻燃共聚酯。采用核磁共振、DSC、元素分析和极限氧指数仪表征阻燃共聚酯的化学组成、序列分布、结晶性能、磷含量和极限氧指数。结果表明：大部分CEPPA单元以无规分布的形式共聚到聚酯分子链中,小部分CEPPA单元以短嵌段的形式共聚在聚酯分子链中,且随着阻燃剂含量增加,无规系数变小。由于分子链的规整性下降,与聚对苯二甲酸乙二酯（PET）相比,阻燃共聚酯的Tg和Tm下降,结晶度减小。随阻燃剂含量的增加,极限氧指数值增加,当阻燃共聚酯中的磷含量达到9．08mg／g时,极限氧指数值达到33％以上。     

环三磷腈类阻燃剂的合成及应用研究进展

简要介绍了制备环三磷腈类阻燃剂所需起始原料六氯环三磷腈的合成方法、合成及取代反应机理;介绍了环三磷腈阻燃剂的阻燃机理;着重阐述了近20年间反应型的羟基/氨基环三磷腈、环氧基环三磷腈、含不饱和双键的环三磷腈、羧基环三磷腈阻燃剂,以及添加型烷氧基环三磷腈、芳氧基环三磷腈的合成及阻燃应用,同时综述了其应用材料的热稳定性能和阻燃性能,并对其发展趋势作了总结和展望。     

Flame retardant epoxy composites with epoxy‐containing polyhedral oligomeric silsesquioxanes

A kind of polyhedral oligomeric silsesquioxanes (POSS) containing the propoxyl‐epoxy and phenyl groups (pr‐ep‐Ph‐POSS) was synthesized via hydrolytic condensation reaction. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry identified the structure of the pr‐ep‐Ph‐POSS, including major caged Si₆O₉ (T6), Si₁₀O₁₅ (T10), Si₁₂O₁₈ (T12), etc. The pr‐ep‐Ph‐POSS was applied into the epoxy resin to achieve EP/pr‐ep‐Ph‐POSS composites. Thermogravimetric analysis indicated that EP/pr‐ep‐Ph‐POSS showed excellent thermal properties than pure EP. The fire behaviors of EP/pr‐ep‐Ph‐POSS composites were evaluated based on the cone calorimetry, limiting oxygen index (LOI), UL‐94 vertical burning test, and smoke density test. The smoke density decreased by ~30%, the LOI value reached to 26.4%, dripping was inhibited, and the peak of heat release rate decreased by ~62%. X‐ray photoelectron spectroscopy analysis and FTIR indicated that protective‐barrier effect is the main flame‐retardant mode of action for pr‐ep‐Ph‐POSS, due to the formation of the Si‐O‐Si, Si‐O‐C, and Si‐C condensed phase, which improve the thermal stability, strength, and integrity of the char layer.     

Formaldehyde-free flame retardant finishing of silk using a hydroxyl-functional organophosphorus oligomer

Flame retardancy is a desirable property for silk textiles, and it becomes necessity when silk textiles are for interior decorative use in building with public access. However, the flame retardant finishing technology available for silk has significant limitations. In this research, we studied the use of the combination of a hydroxyl-functional organophosphorus oligomer (HFPO) and 1,2,3,4-butanetetracarboxylic acid (BTCA) as a formaldehyde-free flame retardant finishing system for silk. When BTCA is applied to silk, most of BTCA reacts with the hydroxyl group on silk by single ester linkage. In the presence of HFPO, BTCA is able to bond HFPO onto silk by either a BTCA “bridge” between silk and HFPO or a BTCA-HFPO-BTCA cross-linkage between two silk protein molecules. We evaluated the flammability and physical properties of the silk fabric treated with HFPO and BTCA. The treated silk fabric demonstrated a high level of flame retardancy with modest loss in fabric tensile strength. The treated silk passed the vertical flammability test after 15 hand wash (HW) cycles. Increasing the HFPO concentration from 20% to 30% does not show significant improvement in the flame retardant performance of the treated silk. The thermal analysis data demonstrated that HFPO reduces silk's initial thermal decomposition temperature and promotes char formation.     

Flame retardant effects of organic inorganic hybrid intumescent flame retardant based on expandable graphite in silicone rubber composites

In this work, an organic inorganic hybrid intumescent flame retardant (functionalized expandable graphite, FEG) was synthesized and characterized by Fourier transform infrared spectrometry (FTIR). The flame retardant effects of FEG in silicone rubber (SR) composites were investigated by cone calorimeter test (CCT), and the thermal stability of SR composites was studied using TGA. The CCT results showed that FEG can effectively reduce the flammable properties including peak heat release rate (PHRR), total heat release (THR), smoke production rate (SPR), total smoke release (TSR), and smoke factor (SF). An improvement of thermal stability of SR/FEG was also observed. Compared with EG, FEG can further reduce THR, SPR, and TSR of SR/FEG composites in combustion process. Moreover, there is a more obvious intumescent char layer formed from the sample with FEG than the sample with EG at the same loading in SR composites. Copyright © 2014 John Wiley & Sons, Ltd.     

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.     

Nanocarbon-poly(methyl methacrylate) composite materials

Nanocarbon-poly(methyl methacrylate) sols were prepared by pulsed laser ablation at the interface of target submerged in flowing liquid (PLA-IT/SFL) method, and the corresponding composite films were prepared by solution-casting. Spectra results indicated that there existed interactions between nanocarbon and the polymethyl methacrylate (PMMA) matrix, which was consistent with the decrease in glass transition temperature of the composites with increase of carbon content. TEM images revealed that a carbon encapsulated core/shell structure was formed in the composites, which could ensure good dispersion of carbon nanoparticles within the PMMA matrix. The decomposition of the composites was less influenced by the introduction of nanocarbon particles. Translated from Acta Polymerica Sinica 2006, 2(2) (in Chinese)     

Photocatalytic degradation of organophosphate flame retardant TBEP: kinetics and identification of transformation products by orbitrap mass spectrometry

The photocatalytic degradation of tris (2–butoxyethyl) phosphate (TBEP) flame retardant using visible light response catalysts TiO₂/V₂O₅, (N,F-doped)-TiO₂/V₂O₅, and N-doped-SrTiO₃ has been studied by high-resolution orbitrap mass spectrometry. TBEP degradation followed first-order kinetics with half-life values ranging between 9.8 and 83.5 min. N-doped-SrTiO₃ was the catalyst with better photocatalytic performance while activity for TiO₂/V₂O₅ composites followed the trend: N, F- TiO₂/V₂O₅ > N-TiO₂/V₂O₅> TiO₂/V₂O₅. The identified degradation products (DPs) revealed hydroxylation, further oxidation and dealkylation as major degradation pathways. Based on the identified DPs and scavenging experiments, ^?OH radical-mediated reactions can be considered for the degradation of TBEP using TiO₂ and SrTiO₃-based photocatalytic materials.     

Azoalkanes: A Novel Class of Flame Retardants

Summary: The synthesis of azoalkanes such as azocyclohexane ( 1 ) and 4,4′‐bis(cyclohexylazocyclohexyl)methane ( 2 ) and their use as flame retardants in polymeric substrates is reported. For the first time it is demonstrated that azoalkanes alone can effectively provide flame retardancy and self‐extinguishing properties to poly(propylene) films at a very low concentration of 0.25 to 0.5 wt.‐%. All the poly(propylene) formulations passed DIN 4102‐1/B2 standards and the instant azoalkane‐containing poly(propylene) blends show no discoloration.

4,4′‐bis(cyclohexylazocyclohexyl)methane.     

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.